Android SAX、DOM、Pull解析xml文件剖析与案例讲解（工具类FastXmlSerializer）

XML介绍

XML(Extensible Markup Language) 即可扩展标记语言，与HTML一样，都是SGML（Standard Generalized Markup Language，标准通用标记语言）。XML是跨平台的，依赖于内容的技术，是当前处理结构化文档信息的有利工具。扩展标记语言XML是一种简单的数据存储语言，使用一系列简单的标记描述数据，而这些标记可以用方便的方式建立，虽然XML占用的空间比二进制数据要占用更多的空间，但XML简单且易于使用。

由于XML扩展性强，致使它需要稳定的基础规则来支持扩展。XML语言规则：

起始和结束的标签相匹配
嵌套标签不能相互嵌套
区分大小写

一、使用SAX解析XML

SAX使用流式处理的方式，当遇到一个标签时，它并不会记录下以前所碰到的标签，也就是说，在startElement()方法中，你所知道的信息，仅仅是当前标签的名字和属性，至于标签的嵌套结构，上层标签的名字，是否有子元素等其他与结构相关的信息，都是不知道的，都需要通过编码来完成。

SAX进行XML解析的整个过程：

SAXParserHandler: ***startDocument()***

SAXParserHandler: startElement uri: localName:persons qName:persons

SAXParserHandler: persons***startElement()***

SAXParserHandler: startElement uri: localName:person qName:person

SAXParserHandler: attributeName:id attributeValue:23

SAXParserHandler: person***startElement()***

SAXParserHandler: startElement uri: localName:name qName:name

SAXParserHandler: name***startElement()***

SAXParserHandler: content: zhangsan

SAXParserHandler: name***endElement()***

SAXParserHandler: startElement uri: localName:age qName:age

SAXParserHandler: age***startElement()***

SAXParserHandler: content: 21

SAXParserHandler: age***endElement()***

SAXParserHandler: person***endElement()***

SAXParserHandler: startElement uri: localName:person qName:person

SAXParserHandler: attributeName:id attributeValue:20

SAXParserHandler: person***startElement()***

SAXParserHandler: startElement uri: localName:name qName:name

SAXParserHandler: name***startElement()***

SAXParserHandler: content: wagnwu

SAXParserHandler: name***endElement()***

SAXParserHandler: startElement uri: localName:age qName:age

SAXParserHandler: age***startElement()***

SAXParserHandler: content: 25

SAXParserHandler: age***endElement()***

SAXParserHandler: person***endElement()***

SAXParserHandler: persons***endElement()***

SAXParserHandler: ***endDocument()***

从上面Log打印的信息可以了解到SAX解析XML的整个过程和顺序。

为简化工作，SAX为DefaultHandler类提供了接口的默认实现，在大多数情况下，为应用程序扩展DefaultHandler并覆盖相关的方法要比直接实现一个接口更容易。

SAX解析xml案例：

1. 创建Android XMLParser工程

2. 创建SAXParserHandler类：

复写方法：startDocument、startElement、characters、endElement、endDocument

3.Person实体类

package com.xml.demo;

public class Person {

private Integer id;

private String name;

private Short age;

public Person() {

}

public Person(Integer id, String name, Short age) {

this.id = id;

this.name = name;

this.age = age;

}

public Person(String name, Short age) {

this.name = name;

this.age = age;

}

public Integer getId() {

return id;

}

public void setId(Integer id) {

this.id = id;

}

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public Short getAge() {

return age;

}

public void setAge(Short age) {

this.age = age;

}

@Override

public String toString() {

return "id=" + id + ",name=" + name + ",age=" + age;

}

4 .assets\test.xml

<?xml version="1.0" encoding="UTF-8"?>

<name>zhangsan</name>

</person>

<name>wangwu</name>

</person>

</persons>

5. SAXParserHandler类：

package com.xml.demo.sax;

import java.util.ArrayList;

import java.util.List;

import org.xml.sax.Attributes;

import org.xml.sax.SAXException;

import org.xml.sax.helpers.DefaultHandler;

import android.util.Log;

import com.xml.demo.Person;

public class SAXParserHandler extends DefaultHandler {

private static final String TAG = "SAXParserHandler";

private List<Person> persons;

private String perTag;// 通过此变量，记录前一个标签的名称。

Person person;// 记录当前Person

public List<Person> getPersons() {

return persons;

}

// 该函数只在开始解析文档时执行一次，比较适合处理一些初始化的行为

public void startDocument() throws SAXException {

persons = new ArrayList<Person>();

Log.i(TAG, "***startDocument()***");

}

public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {

Log.i(TAG, "startElement uri:" + uri + " localName:" + localName + " qName:" + qName);

if ("person".equals(localName)) {

for (int i = 0; i < attributes.getLength(); i++) {

Log.i(TAG, "attributeName:" + attributes.getLocalName(i) + " attributeValue:" + attributes.getValue(i));

person = new Person();

person.setId(Integer.valueOf(attributes.getValue(i)));

}

perTag = localName;

Log.i(TAG, qName + "***startElement()***");

}

public void characters(char[] ch, int start, int length) throws SAXException {

String data = new String(ch, start, length).trim();

if (!"".equals(data.trim())) {

Log.i(TAG, "content: " + data.trim());

}

if ("name".equals(perTag)) {

person.setName(data);

} else if ("age".equals(perTag)) {

person.setAge(new Short(data));

}

public void endElement(String uri, String localName, String qName) throws SAXException {

Log.i(TAG, qName + "***endElement()***");

if ("person".equals(localName)) {

persons.add(person);

person = null;

}

perTag = null;

}

public void endDocument() throws SAXException {

Log.i(TAG, "***endDocument()***");

}

6.MainActivity类：

package com.xml.demo;

import java.io.IOException;

import java.io.InputStream;

import java.util.List;

import javax.xml.parsers.ParserConfigurationException;

import javax.xml.parsers.SAXParser;

import javax.xml.parsers.SAXParserFactory;

import org.xml.sax.SAXException;

import android.app.Activity;

import android.content.res.AssetManager;

import android.os.Bundle;

import android.util.Log;

import com.xml.demo.sax.SAXParserHandler;

public class MainActivity extends Activity {

String TAG = "ZZMainActivity";

private AssetManager mAssetManager;

private InputStream mInputStream;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

mAssetManager = getApplicationContext().getAssets();

try {

mInputStream = mAssetManager.open("test.xml");

} catch (IOException e) {

e.printStackTrace();

}

testSAXParser();

}

private void testSAXParser() {

SAXParserHandler saxForHandler = new SAXParserHandler();

SAXParserFactory spf = SAXParserFactory.newInstance();

SAXParser saxParser = null;

try {

saxParser = spf.newSAXParser();

saxParser.parse(mInputStream, saxForHandler);

List<Person> persons = saxForHandler.getPersons();

for (Person person : persons) {

Log.i(TAG, person.toString());

}

} catch (ParserConfigurationException e) {

e.printStackTrace();

} catch (SAXException e) {

e.printStackTrace();

} catch (IOException e) {

e.printStackTrace();

}

SAX以流的方式接收指定的XML内容。通过上面SAX解析过程，要清楚，遇到哪些字符，会触发哪些事件，触发的顺序又是怎么样。

二、使用DOM解析XML(不推荐使用)

DOX 是一种用于XML文档的对象模型，可用于直接访问XML文档的各个部分。没有涉及回调和复杂的状态管理，然后，DOM实现常常将所有XML节点保存到内存中，这使较大的文档效率低下。

通过DOM将XML文档作为一个树形结构，这种树形街结构也被称为节点树

DOM是这样规定的：

整个文档是一个文档节点；
每个XML元素标签是一个元素节点；
包含在XML元素中的文本是文本节点；
每一个XML属性是一个属性节点；
注释属于注释节点。

节点树中的节点之间彼此都有等级关系。

在节点树中，顶端的节点成为根节点；

根节点之外的每个节点都有一个父节点；

节点可以有任何数量的子节点；

叶子是没有子节点的节点；

同级节点是拥有相同父节点的节点。

示例：

1. DOMParserHandler

package com.xml.demo.dom;

import java.io.InputStream;

import java.util.ArrayList;

import java.util.List;

import javax.xml.parsers.DocumentBuilder;

import javax.xml.parsers.DocumentBuilderFactory;

import org.w3c.dom.Document;

import org.w3c.dom.Element;

import org.w3c.dom.Node;

import org.w3c.dom.NodeList;

import com.xml.demo.Person;

public class DOMParserHandler {

private static final String TAG = "DOMParserHandler";

public static List<Person> getPersons(InputStream inStream) throws Exception {

List<Person> persons = new ArrayList<Person>();

DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();

DocumentBuilder builder = factory.newDocumentBuilder();

Document document = builder.parse(inStream);

Element root = document.getDocumentElement();

NodeList personNodes = root.getElementsByTagName("person");

for (int i = 0; i < personNodes.getLength(); i++) {

Element personElement = (Element) personNodes.item(i);

int id = Integer.valueOf(personElement.getAttribute("id"));

Person person = new Person();

person.setId(id);

NodeList childNodes = personElement.getChildNodes();

for (int y = 0; y < childNodes.getLength(); y++) {

if (childNodes.item(y).getNodeType() == Node.ELEMENT_NODE) {

if ("name".equals(childNodes.item(y).getNodeName())) {

String name = childNodes.item(y).getFirstChild().getNodeValue();

person.setName(name);

} else if ("age".equals(childNodes.item(y).getNodeName())) {

String age = childNodes.item(y).getFirstChild().getNodeValue();

person.setAge(new Short(age));

}

persons.add(person);

}

inStream.close();

return persons;

}

package com.xml.demo;

import java.io.IOException;

import java.io.InputStream;

import java.util.List;

import android.app.Activity;

import android.content.res.AssetManager;

import android.os.Bundle;

import android.util.Log;

import com.xml.demo.dom.DOMParserHandler;

public class MainActivity extends Activity {

String TAG = "ZZMainActivity";

private AssetManager mAssetManager;

private InputStream mInputStream;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

mAssetManager = getApplicationContext().getAssets();

try {

mInputStream = mAssetManager.open("test.xml");

} catch (IOException e) {

e.printStackTrace();

}

testDOMParser();

}

private void testDOMParser() {

try {

List<Person> persons = DOMParserHandler.getPersons(mInputStream);

for (Person person : persons) {

Log.i(TAG, person.toString());

}

} catch (Exception e) {

e.printStackTrace();

}

三、使用PULL解析XML(推荐使用这种方式)

PULL是Android系统内置的解析器，但不仅限于Android使用

Pull解析器的运行方式和SAX解析器相似。它提供了类似的事件，如开始元素和结束元素事件。使用parser.next()可以进入下一个元素并触发相应事件。事件将作为数值代码被发送，因此可以使用一个switch对感兴趣的事件进行选择，然后进行相应处理。当元素开始解析时，调用parser.nextText()方法可以获取下一个Text类型元素的值。

Pull解析器只有一个重要的方法next();它被用来检索下一个事件。而它的事件也仅仅只有5个：

START_DOCUMENT(开始解析)
START_TAG(开始元素)
TEXT(解析文本)
END_TAG(结束元素)
END_DOCUMENT(结束解析)

解析XML内容的方式与SAX是相似的，同样包括开始元素和结束元素事件，使用parser.next()可以进入下一个元素并触发相应事件。但是他们不同的是，SAX的事件驱动是回调相应方法，需要提供回调的方法，而后在SAX内部自动调用相应的方法。而pull解析器并没有强制要求提供触发的方法。因为它触发的事件并不是一个方法，而是一个数字。至于触发的事件要不要处理，由程序员自己决定。

示例：

1. PullParserHandler

package com.xml.demo.pull;

import java.io.InputStream;

import java.util.ArrayList;

import java.util.List;

import org.xmlpull.v1.XmlPullParser;

import android.util.Xml;

import com.xml.demo.Person;

public class PullParserHandler {

private static final String TAG = "PullParserHandler";

public static List<Person> getPersons(InputStream inStream) throws Exception {

Person person = null;

List<Person> persons = null;

XmlPullParser pullParser = Xml.newPullParser();

pullParser.setInput(inStream, "UTF-8");

int event = pullParser.getEventType();// 触发第一个事件

while (event != XmlPullParser.END_DOCUMENT) {

switch (event) {

case XmlPullParser.START_DOCUMENT:

persons = new ArrayList<Person>();

break;

case XmlPullParser.START_TAG:

if ("person".equals(pullParser.getName())) {

int id = Integer.valueOf(pullParser.getAttributeValue(0));

person = new Person();

person.setId(id);

}

if (person != null) {

if ("name".equals(pullParser.getName())) {

person.setName(pullParser.nextText());

}

if ("age".equals(pullParser.getName())) {

person.setAge(new Short(pullParser.nextText()));

}

break;

case XmlPullParser.END_TAG:

if ("person".equals(pullParser.getName())) {

persons.add(person);

person = null;

}

break;

}

event = pullParser.next();

}

return persons;

}

说明：

a. “int event = pullParser.getEventType()”是pull解析器的第一个事件，这个方法的返回值是int类型，这就是前面提到的pull解析器返回的是一个数字，类似于一个信号。那么这些信号都代表什么意思呢？Pull解析器已经定义了这五个常亮，而且对于事件，仅仅只有这5个，如下：

START_DOCUMENT(开始解析)
START_TAG(开始元素)
TEXT(解析文本)
END_TAG(结束元素)
END_DOCUMENT(结束解析)

b. pullParser.getEventType()触发了第一个事件，根据XML的语法，也就是从它开始了解析文档。那么，怎么样触发下一个事件呢？要通过parser中最重要的方法：

pullParser.next()

注意：该方法是有返回值的，在Pull触发下一个事件的同时，也获得该事件的“信号”。通过获得的信号进行switch操作。

c. pullParser.getAttributeValue获得相应属性的值。它有两种形式，可以通过属性的索引，也可以通过(命名空间，属性名)进行索引。

2. MainActivity

package com.xml.demo;

import java.io.IOException;

import java.io.InputStream;

import java.util.List;

import android.app.Activity;

import android.content.res.AssetManager;

import android.os.Bundle;

import android.util.Log;

import com.xml.demo.pull.PullParserHandler;

public class MainActivity extends Activity {

String TAG = "ZZMainActivity";

private AssetManager mAssetManager;

private InputStream mInputStream;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

mAssetManager = getApplicationContext().getAssets();

try {

mInputStream = mAssetManager.open("test.xml");

} catch (IOException e) {

e.printStackTrace();

}

testPullParser();

}

private void testPullParser() {

List<Person> persons;

try {

persons = PullParserHandler.getPersons(mInputStream);

if (persons != null) {

for (Person person : persons) {

Log.i(TAG, person.toString());

}

} catch (Exception e) {

e.printStackTrace();

}

四、使用PULL生成XML

SAX不支持xml文件的修改、生成，下面介绍下如何使用Pull来生成一个XML

XML中的标签时成对出现的，又开始，必有结束，所以在写入一个startTag()时，笔者习惯紧跟着写入与之相对应的endTag()，这样不至于在复杂的生成结构时，弄错了XML生成结构

示例1：

1. PullParserHandler.java

package com.xml.demo.pull;

import java.io.OutputStream;

import java.util.List;

import org.xmlpull.v1.XmlSerializer;

import android.util.Xml;

import com.xml.demo.Person;

public class PullParserHandler {

private static final String TAG = "PullParserHandler";

public static void save(List<Person> persons, OutputStream outStream) throws Exception {

XmlSerializer serializer = Xml.newSerializer();

serializer.setOutput(outStream, "UTF-8");

serializer.startDocument("UTF-8", true);

serializer.startTag(null, "persons");

for (Person person : persons) {

serializer.startTag(null, "person");

serializer.attribute(null, "id", person.getId().toString());

serializer.startTag(null, "name");

serializer.text(person.getName());

serializer.endTag(null, "name");

serializer.startTag(null, "age");

serializer.text(person.getAge().toString());

serializer.endTag(null, "age");

serializer.endTag(null, "person");

}

serializer.endTag(null, "persons");

serializer.endDocument();

outStream.flush();

outStream.close();

}

2. MainActivity.java

package com.xml.demo;

import java.io.File;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.InputStream;

import java.util.ArrayList;

import java.util.List;

import android.app.Activity;

import android.content.res.AssetManager;

import android.os.Bundle;

import com.xml.demo.pull.PullParserHandler;

public class MainActivity extends Activity {

String TAG = "ZZMainActivity";

private AssetManager mAssetManager;

private InputStream mInputStream;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

testSaveXml();

}

private void testSaveXml() {

File file = new File(this.getFilesDir(), "toXmlFile.xml");

FileOutputStream outStream;

try {

outStream = new FileOutputStream(file);

List<Person> persons = new ArrayList<Person>();

persons.add(new Person(90, "zhangsan", (short) 13));

persons.add(new Person(35, "wangwu", (short) 23));

persons.add(new Person(78, "zhaoliu", (short) 33));

PullParserHandler.save(persons, outStream);

} catch (FileNotFoundException e) {

e.printStackTrace();

} catch (Exception e) {

e.printStackTrace();

}

上述生成的xml文件保存在 /data/data/com.xml.demo/files目录下：

<?xml version='1.0' encoding='UTF-8' standalone='yes' ?><persons><person id="90"><name>zhangsan</name><age>13</age></person><person id="35"><name>wangwu</name><age>23</age></person><person id="78"><name>zhaoliu</name><age>33</age></person></persons>

示例2：

使用Android提供的工具类：FastXmlSerializer.java 和 XmlUtils.java 来生成xml文件，生成的xml文件是格式化后的，比较容易阅读，推荐使用

1. 工具类：FastXmlSerializer.java

package com.xml.demo.utils;

import java.io.IOException;

import java.io.OutputStream;

import java.io.OutputStreamWriter;

import java.io.UnsupportedEncodingException;

import java.io.Writer;

import java.nio.ByteBuffer;

import java.nio.CharBuffer;

import java.nio.charset.Charset;

import java.nio.charset.CharsetEncoder;

import java.nio.charset.CoderResult;

import java.nio.charset.IllegalCharsetNameException;

import java.nio.charset.UnsupportedCharsetException;

import org.xmlpull.v1.XmlSerializer;

// copy from frameworks/base/core/java/com/android/internal/util/FastXmlSerializer.java 1.6

/**

* This is a quick and dirty implementation of XmlSerializer that isn't horribly

* painfully slow like the normal one. It only does what is needed for the

* specific XML files being written with it.

public class FastXmlSerializer implements XmlSerializer {

private static final String ESCAPE_TABLE[] = new String[] { null, null, null, null, null, null, null, null, // 0-7

null, null, null, null, null, null, null, null, // 8-15

null, null, null, null, null, null, null, null, // 16-23

null, null, null, null, null, null, null, null, // 24-31

null, null, """, null, null, null, "&", null, // 32-39

null, null, null, null, null, null, null, null, // 40-47

null, null, null, null, null, null, null, null, // 48-55

null, null, null, null, "<", null, ">", null, // 56-63

};

private static final int BUFFER_LEN = 8192;

private final char[] mText = new char[BUFFER_LEN];

private int mPos;

private Writer mWriter;

private OutputStream mOutputStream;

private CharsetEncoder mCharset;

private ByteBuffer mBytes = ByteBuffer.allocate(BUFFER_LEN);

private boolean mInTag;

private void append(char c) throws IOException {

int pos = mPos;

if (pos >= (BUFFER_LEN - 1)) {

flush();

pos = mPos;

}

mText[pos] = c;

mPos = pos + 1;

}

private void append(String str, int i, final int length) throws IOException {

if (length > BUFFER_LEN) {

final int end = i + length;

while (i < end) {

int next = i + BUFFER_LEN;

append(str, i, next < end ? BUFFER_LEN : (end - i));

i = next;

}

return;

}

int pos = mPos;

if ((pos + length) > BUFFER_LEN) {

flush();

pos = mPos;

}

str.getChars(i, i + length, mText, pos);

mPos = pos + length;

}

private void append(char[] buf, int i, final int length) throws IOException {

if (length > BUFFER_LEN) {

final int end = i + length;

while (i < end) {

int next = i + BUFFER_LEN;

append(buf, i, next < end ? BUFFER_LEN : (end - i));

i = next;

}

return;

}

int pos = mPos;

if ((pos + length) > BUFFER_LEN) {

flush();

pos = mPos;

}

System.arraycopy(buf, i, mText, pos, length);

mPos = pos + length;

}

private void append(String str) throws IOException {

append(str, 0, str.length());

}

private void escapeAndAppendString(final String string) throws IOException {

final int N = string.length();

final char NE = (char) ESCAPE_TABLE.length;

final String[] escapes = ESCAPE_TABLE;

int lastPos = 0;

int pos;

for (pos = 0; pos < N; pos++) {

char c = string.charAt(pos);

if (c >= NE)

continue;

String escape = escapes[c];

if (escape == null)

continue;

if (lastPos < pos)

append(string, lastPos, pos - lastPos);

lastPos = pos + 1;

append(escape);

}

if (lastPos < pos)

append(string, lastPos, pos - lastPos);

}

private void escapeAndAppendString(char[] buf, int start, int len) throws IOException {

final char NE = (char) ESCAPE_TABLE.length;

final String[] escapes = ESCAPE_TABLE;

int end = start + len;

int lastPos = start;

int pos;

for (pos = start; pos < end; pos++) {

char c = buf[pos];

if (c >= NE)

continue;

String escape = escapes[c];

if (escape == null)

continue;

if (lastPos < pos)

append(buf, lastPos, pos - lastPos);

lastPos = pos + 1;

append(escape);

}

if (lastPos < pos)

append(buf, lastPos, pos - lastPos);

}

public XmlSerializer attribute(String namespace, String name, String value) throws IOException, IllegalArgumentException, IllegalStateException {

append(' ');

if (namespace != null) {

append(namespace);

append(':');

}

append(name);

append("=\"");

escapeAndAppendString(value);

append('"');

return this;

}

public void cdsect(String text) throws IOException, IllegalArgumentException, IllegalStateException {

throw new UnsupportedOperationException();

}

public void comment(String text) throws IOException, IllegalArgumentException, IllegalStateException {

throw new UnsupportedOperationException();

}

public void docdecl(String text) throws IOException, IllegalArgumentException, IllegalStateException {

throw new UnsupportedOperationException();

}

public void endDocument() throws IOException, IllegalArgumentException, IllegalStateException {

flush();

}

public XmlSerializer endTag(String namespace, String name) throws IOException, IllegalArgumentException, IllegalStateException {

if (mInTag) {

append(" />\n");

} else {

append("</");

if (namespace != null) {

append(namespace);

append(':');

}

append(name);

append(">\n");

}

mInTag = false;

return this;

}

public void entityRef(String text) throws IOException, IllegalArgumentException, IllegalStateException {

throw new UnsupportedOperationException();

}

private void flushBytes() throws IOException {

int position;

if ((position = mBytes.position()) > 0) {

mBytes.flip();

mOutputStream.write(mBytes.array(), 0, position);

mBytes.clear();

}

public void flush() throws IOException {

// Log.i("PackageManager", "flush mPos=" + mPos);

if (mPos > 0) {

if (mOutputStream != null) {

CharBuffer charBuffer = CharBuffer.wrap(mText, 0, mPos);

CoderResult result = mCharset.encode(charBuffer, mBytes, true);

while (true) {

if (result.isError()) {

throw new IOException(result.toString());

} else if (result.isOverflow()) {

flushBytes();

result = mCharset.encode(charBuffer, mBytes, true);

continue;

}

break;

}

flushBytes();

mOutputStream.flush();

} else {

mWriter.write(mText, 0, mPos);

mWriter.flush();

}

mPos = 0;

}

public int getDepth() {

throw new UnsupportedOperationException();

}

public boolean getFeature(String name) {

throw new UnsupportedOperationException();

}

public String getName() {

throw new UnsupportedOperationException();

}

public String getNamespace() {

throw new UnsupportedOperationException();

}

public String getPrefix(String namespace, boolean generatePrefix) throws IllegalArgumentException {

throw new UnsupportedOperationException();

}

public Object getProperty(String name) {

throw new UnsupportedOperationException();

}

public void ignorableWhitespace(String text) throws IOException, IllegalArgumentException, IllegalStateException {

throw new UnsupportedOperationException();

}

public void processingInstruction(String text) throws IOException, IllegalArgumentException, IllegalStateException {

throw new UnsupportedOperationException();

}

public void setFeature(String name, boolean state) throws IllegalArgumentException, IllegalStateException {

if (name.equals("http://xmlpull.org/v1/doc/features.html#indent-output")) {

return;

}

throw new UnsupportedOperationException();

}

public void setOutput(OutputStream os, String encoding) throws IOException, IllegalArgumentException, IllegalStateException {

if (os == null)

throw new IllegalArgumentException();

if (true) {

try {

mCharset = Charset.forName(encoding).newEncoder();

} catch (IllegalCharsetNameException e) {

throw (UnsupportedEncodingException) (new UnsupportedEncodingException(encoding).initCause(e));

} catch (UnsupportedCharsetException e) {

throw (UnsupportedEncodingException) (new UnsupportedEncodingException(encoding).initCause(e));

}

mOutputStream = os;

} else {

setOutput(encoding == null ? new OutputStreamWriter(os) : new OutputStreamWriter(os, encoding));

}

public void setOutput(Writer writer) throws IOException, IllegalArgumentException, IllegalStateException {

mWriter = writer;

}

public void setPrefix(String prefix, String namespace) throws IOException, IllegalArgumentException, IllegalStateException {

throw new UnsupportedOperationException();

}

public void setProperty(String name, Object value) throws IllegalArgumentException, IllegalStateException {

throw new UnsupportedOperationException();

}

public void startDocument(String encoding, Boolean standalone) throws IOException, IllegalArgumentException, IllegalStateException {

append("<?xml version='1.0' encoding='utf-8' standalone='" + (standalone ? "yes" : "no") + "' ?>\n");

}

public XmlSerializer startTag(String namespace, String name) throws IOException, IllegalArgumentException, IllegalStateException {

if (mInTag) {

append(">\n");

}

append('<');

if (namespace != null) {

append(namespace);

append(':');

}

append(name);

mInTag = true;

return this;

}

public XmlSerializer text(char[] buf, int start, int len) throws IOException, IllegalArgumentException, IllegalStateException {

if (mInTag) {

append(">");

mInTag = false;

}

escapeAndAppendString(buf, start, len);

return this;

}

public XmlSerializer text(String text) throws IOException, IllegalArgumentException, IllegalStateException {

if (mInTag) {

append(">");

mInTag = false;

}

escapeAndAppendString(text);

return this;

}

2. 工具类：XmlUtils.java

package com.xml.demo.utils;

import java.io.IOException;

import java.io.InputStream;

import java.io.OutputStream;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.Iterator;

import java.util.List;

import java.util.Map;

import java.util.Set;

import org.xmlpull.v1.XmlPullParser;

import org.xmlpull.v1.XmlPullParserException;

import org.xmlpull.v1.XmlSerializer;

import android.util.Xml;

// copy from frameworks/base/core/java/com/android/internal/util/XmlUtils.java 1.6

public class XmlUtils {

public static void skipCurrentTag(XmlPullParser parser) throws XmlPullParserException, IOException {

int outerDepth = parser.getDepth();

int type;

while ((type = parser.next()) != XmlPullParser.END_DOCUMENT && (type != XmlPullParser.END_TAG || parser.getDepth() > outerDepth)) {

}

public static final int convertValueToList(CharSequence value, String[] options, int defaultValue) {

if (null != value) {

for (int i = 0; i < options.length; i++) {

if (value.equals(options[i]))

return i;

}

return defaultValue;

}

public static final boolean convertValueToBoolean(CharSequence value, boolean defaultValue) {

boolean result = false;

if (null == value)

return defaultValue;

if (value.equals("1") || value.equals("true") || value.equals("TRUE"))

result = true;

return result;

}

public static final int convertValueToInt(CharSequence charSeq, int defaultValue) {

if (null == charSeq)

return defaultValue;

String nm = charSeq.toString();

// XXX This code is copied from Integer.decode() so we don't

// have to instantiate an Integer!

int value;

int sign = 1;

int index = 0;

int len = nm.length();

int base = 10;

if ('-' == nm.charAt(0)) {

sign = -1;

index++;

}

if ('0' == nm.charAt(index)) {

// Quick check for a zero by itself

if (index == (len - 1))

return 0;

char c = nm.charAt(index + 1);

if ('x' == c || 'X' == c) {

index += 2;

base = 16;

} else {

index++;

base = 8;

}

} else if ('#' == nm.charAt(index)) {

index++;

base = 16;

}

return Integer.parseInt(nm.substring(index), base) * sign;

}

public static final int convertValueToUnsignedInt(String value, int defaultValue) {

if (null == value)

return defaultValue;

return parseUnsignedIntAttribute(value);

}

public static final int parseUnsignedIntAttribute(CharSequence charSeq) {

String value = charSeq.toString();

long bits;

int index = 0;

int len = value.length();

int base = 10;

if ('0' == value.charAt(index)) {

// Quick check for zero by itself

if (index == (len - 1))

return 0;

char c = value.charAt(index + 1);

if ('x' == c || 'X' == c) { // check for hex

index += 2;

base = 16;

} else { // check for octal

index++;

base = 8;

}

} else if ('#' == value.charAt(index)) {

index++;

base = 16;

}

return (int) Long.parseLong(value.substring(index), base);

}

/**

* Flatten a Map into an output stream as XML. The map can later be read

* back with readMapXml().

* @param val

* The map to be flattened.

* @param out

* Where to write the XML data.

* @see #writeMapXml(Map, String, XmlSerializer)

* @see #writeListXml

* @see #writeValueXml

* @see #readMapXml

public static final void writeMapXml(Map val, OutputStream out) throws XmlPullParserException, java.io.IOException {

XmlSerializer serializer = new FastXmlSerializer();

serializer.setOutput(out, "utf-8");

serializer.startDocument(null, true);

serializer.setFeature("http://xmlpull.org/v1/doc/features.html#indent-output", true);

writeMapXml(val, null, serializer);

serializer.endDocument();

}

/**

* Flatten a List into an output stream as XML. The list can later be read

* back with readListXml().

* @param val

* The list to be flattened.

* @param out

* Where to write the XML data.

* @see #writeListXml(List, String, XmlSerializer)

* @see #writeMapXml

* @see #writeValueXml

* @see #readListXml

public static final void writeListXml(List val, OutputStream out) throws XmlPullParserException, java.io.IOException {

XmlSerializer serializer = Xml.newSerializer();

serializer.setOutput(out, "utf-8");

serializer.startDocument(null, true);

serializer.setFeature("http://xmlpull.org/v1/doc/features.html#indent-output", true);

writeListXml(val, null, serializer);

serializer.endDocument();

}

/**

* Flatten a Map into an XmlSerializer. The map can later be read back with

* readThisMapXml().

* @param val

* The map to be flattened.

* @param name

* Name attribute to include with this list's tag, or null for

* none.

* @param out

* XmlSerializer to write the map into.

* @see #writeMapXml(Map, OutputStream)

* @see #writeListXml

* @see #writeValueXml

* @see #readMapXml

public static final void writeMapXml(Map val, String name, XmlSerializer out) throws XmlPullParserException, java.io.IOException {

if (val == null) {

out.startTag(null, "null");

out.endTag(null, "null");

return;

}

Set s = val.entrySet();

Iterator i = s.iterator();

out.startTag(null, "map");

if (name != null) {

out.attribute(null, "name", name);

}

while (i.hasNext()) {

Map.Entry e = (Map.Entry) i.next();

writeValueXml(e.getValue(), (String) e.getKey(), out);

}

out.endTag(null, "map");

}

/**

* Flatten a List into an XmlSerializer. The list can later be read back

* with readThisListXml().

* @param val

* The list to be flattened.

* @param name

* Name attribute to include with this list's tag, or null for

* none.

* @param out

* XmlSerializer to write the list into.

* @see #writeListXml(List, OutputStream)

* @see #writeMapXml

* @see #writeValueXml

* @see #readListXml

public static final void writeListXml(List val, String name, XmlSerializer out) throws XmlPullParserException, java.io.IOException {

if (val == null) {

out.startTag(null, "null");

out.endTag(null, "null");

return;

}

out.startTag(null, "list");

if (name != null) {

out.attribute(null, "name", name);

}

int N = val.size();

int i = 0;

while (i < N) {

writeValueXml(val.get(i), null, out);

i++;

}

out.endTag(null, "list");

}

/**

* Flatten a byte[] into an XmlSerializer. The list can later be read back

* with readThisByteArrayXml().

* @param val

* The byte array to be flattened.

* @param name

* Name attribute to include with this array's tag, or null for

* none.

* @param out

* XmlSerializer to write the array into.

* @see #writeMapXml

* @see #writeValueXml

public static final void writeByteArrayXml(byte[] val, String name, XmlSerializer out) throws XmlPullParserException, java.io.IOException {

if (val == null) {

out.startTag(null, "null");

out.endTag(null, "null");

return;

}

out.startTag(null, "byte-array");

if (name != null) {

out.attribute(null, "name", name);

}

final int N = val.length;

out.attribute(null, "num", Integer.toString(N));

StringBuilder sb = new StringBuilder(val.length * 2);

for (int i = 0; i < N; i++) {

int b = val[i];

int h = b >> 4;

sb.append(h >= 10 ? ('a' + h - 10) : ('0' + h));

h = b & 0xff;

sb.append(h >= 10 ? ('a' + h - 10) : ('0' + h));

}

out.text(sb.toString());

out.endTag(null, "byte-array");

}

/**

* Flatten an int[] into an XmlSerializer. The list can later be read back

* with readThisIntArrayXml().

* @param val

* The int array to be flattened.

* @param name

* Name attribute to include with this array's tag, or null for

* none.

* @param out

* XmlSerializer to write the array into.

* @see #writeMapXml

* @see #writeValueXml

* @see #readThisIntArrayXml

public static final void writeIntArrayXml(int[] val, String name, XmlSerializer out) throws XmlPullParserException, java.io.IOException {

if (val == null) {

out.startTag(null, "null");

out.endTag(null, "null");

return;

}

out.startTag(null, "int-array");

if (name != null) {

out.attribute(null, "name", name);

}

final int N = val.length;

out.attribute(null, "num", Integer.toString(N));

for (int i = 0; i < N; i++) {

out.startTag(null, "item");

out.attribute(null, "value", Integer.toString(val[i]));

out.endTag(null, "item");

}

out.endTag(null, "int-array");

}

/**

* Flatten an object's value into an XmlSerializer. The value can later be

* read back with readThisValueXml().

* Currently supported value types are: null, String, Integer, Long, Float,

* Double Boolean, Map, List.

* @param v

* The object to be flattened.

* @param name

* Name attribute to include with this value's tag, or null for

* none.

* @param out

* XmlSerializer to write the object into.

* @see #writeMapXml

* @see #writeListXml

* @see #readValueXml

public static final void writeValueXml(Object v, String name, XmlSerializer out) throws XmlPullParserException, java.io.IOException {

String typeStr;

if (v == null) {

out.startTag(null, "null");

if (name != null) {

out.attribute(null, "name", name);

}

out.endTag(null, "null");

return;

} else if (v instanceof String) {

out.startTag(null, "string");

if (name != null) {

out.attribute(null, "name", name);

}

out.text(v.toString());

out.endTag(null, "string");

return;

} else if (v instanceof Integer) {

typeStr = "int";

} else if (v instanceof Long) {

typeStr = "long";

} else if (v instanceof Float) {

typeStr = "float";

} else if (v instanceof Double) {

typeStr = "double";

} else if (v instanceof Boolean) {

typeStr = "boolean";

} else if (v instanceof byte[]) {

writeByteArrayXml((byte[]) v, name, out);

return;

} else if (v instanceof int[]) {

writeIntArrayXml((int[]) v, name, out);

return;

} else if (v instanceof Map) {

writeMapXml((Map) v, name, out);

return;

} else if (v instanceof List) {

writeListXml((List) v, name, out);

return;

} else if (v instanceof CharSequence) {

// XXX This is to allow us to at least write something if

// we encounter styled text... but it means we will drop all

// of the styling information. :(

out.startTag(null, "string");

if (name != null) {

out.attribute(null, "name", name);

}

out.text(v.toString());

out.endTag(null, "string");

return;

} else {

throw new RuntimeException("writeValueXml: unable to write value " + v);

}

out.startTag(null, typeStr);

if (name != null) {

out.attribute(null, "name", name);

}

out.attribute(null, "value", v.toString());

out.endTag(null, typeStr);

}

/**

* Read a HashMap from an InputStream containing XML. The stream can

* previously have been written by writeMapXml().

* @param in

* The InputStream from which to read.

* @return HashMap The resulting map.

* @see #readListXml

* @see #readValueXml

* @see #readThisMapXml #see #writeMapXml

public static final HashMap readMapXml(InputStream in) throws XmlPullParserException, java.io.IOException {

XmlPullParser parser = Xml.newPullParser();

parser.setInput(in, null);

return (HashMap) readValueXml(parser, new String[1]);

}

/**

* Read an ArrayList from an InputStream containing XML. The stream can

* previously have been written by writeListXml().

* @param in

* The InputStream from which to read.

* @return HashMap The resulting list.

* @see #readMapXml

* @see #readValueXml

* @see #readThisListXml

* @see #writeListXml

public static final ArrayList readListXml(InputStream in) throws XmlPullParserException, java.io.IOException {

XmlPullParser parser = Xml.newPullParser();

parser.setInput(in, null);

return (ArrayList) readValueXml(parser, new String[1]);

}

/**

* Read a HashMap object from an XmlPullParser. The XML data could

* previously have been generated by writeMapXml(). The XmlPullParser must

* be positioned after the tag that begins the map.

* @param parser

* The XmlPullParser from which to read the map data.

* @param endTag

* Name of the tag that will end the map, usually "map".

* @param name

* An array of one string, used to return the name attribute of

* the map's tag.

* @return HashMap The newly generated map.

* @see #readMapXml

public static final HashMap readThisMapXml(XmlPullParser parser, String endTag, String[] name) throws XmlPullParserException, java.io.IOException {

HashMap map = new HashMap();

int eventType = parser.getEventType();

do {

if (eventType == parser.START_TAG) {

Object val = readThisValueXml(parser, name);

if (name[0] != null) {

// System.out.println("Adding to map: " + name + " -> " +

// val);

map.put(name[0], val);

} else {

throw new XmlPullParserException("Map value without name attribute: " + parser.getName());

}

} else if (eventType == parser.END_TAG) {

if (parser.getName().equals(endTag)) {

return map;

}

throw new XmlPullParserException("Expected " + endTag + " end tag at: " + parser.getName());

}

eventType = parser.next();

} while (eventType != parser.END_DOCUMENT);

throw new XmlPullParserException("Document ended before " + endTag + " end tag");

}

/**

* Read an ArrayList object from an XmlPullParser. The XML data could

* previously have been generated by writeListXml(). The XmlPullParser must

* be positioned after the tag that begins the list.

* @param parser

* The XmlPullParser from which to read the list data.

* @param endTag

* Name of the tag that will end the list, usually "list".

* @param name

* An array of one string, used to return the name attribute of

* the list's tag.

* @return HashMap The newly generated list.

* @see #readListXml

public static final ArrayList readThisListXml(XmlPullParser parser, String endTag, String[] name) throws XmlPullParserException, java.io.IOException {

ArrayList list = new ArrayList();

int eventType = parser.getEventType();

do {

if (eventType == parser.START_TAG) {

Object val = readThisValueXml(parser, name);

list.add(val);

// System.out.println("Adding to list: " + val);

} else if (eventType == parser.END_TAG) {

if (parser.getName().equals(endTag)) {

return list;

}

throw new XmlPullParserException("Expected " + endTag + " end tag at: " + parser.getName());

}

eventType = parser.next();

} while (eventType != parser.END_DOCUMENT);

throw new XmlPullParserException("Document ended before " + endTag + " end tag");

}

/**

* Read an int[] object from an XmlPullParser. The XML data could previously

* have been generated by writeIntArrayXml(). The XmlPullParser must be

* positioned after the tag that begins the list.

* @param parser

* The XmlPullParser from which to read the list data.

* @param endTag

* Name of the tag that will end the list, usually "list".

* @param name

* An array of one string, used to return the name attribute of

* the list's tag.

* @return Returns a newly generated int[].

* @see #readListXml

public static final int[] readThisIntArrayXml(XmlPullParser parser, String endTag, String[] name) throws XmlPullParserException, java.io.IOException {

int num;

try {

num = Integer.parseInt(parser.getAttributeValue(null, "num"));

} catch (NullPointerException e) {

throw new XmlPullParserException("Need num attribute in byte-array");

} catch (NumberFormatException e) {

throw new XmlPullParserException("Not a number in num attribute in byte-array");

}

int[] array = new int[num];

int i = 0;

int eventType = parser.getEventType();

do {

if (eventType == parser.START_TAG) {

if (parser.getName().equals("item")) {

try {

array[i] = Integer.parseInt(parser.getAttributeValue(null, "value"));

} catch (NullPointerException e) {

throw new XmlPullParserException("Need value attribute in item");

} catch (NumberFormatException e) {

throw new XmlPullParserException("Not a number in value attribute in item");

}

} else {

throw new XmlPullParserException("Expected item tag at: " + parser.getName());

}

} else if (eventType == parser.END_TAG) {

if (parser.getName().equals(endTag)) {

return array;

} else if (parser.getName().equals("item")) {

i++;

} else {

throw new XmlPullParserException("Expected " + endTag + " end tag at: " + parser.getName());

}

eventType = parser.next();

} while (eventType != parser.END_DOCUMENT);

throw new XmlPullParserException("Document ended before " + endTag + " end tag");

}

/**

* Read a flattened object from an XmlPullParser. The XML data could

* previously have been written with writeMapXml(), writeListXml(), or

* writeValueXml(). The XmlPullParser must be positioned at the tag

* that defines the value.

* @param parser

* The XmlPullParser from which to read the object.

* @param name

* An array of one string, used to return the name attribute of

* the value's tag.

* @return Object The newly generated value object.

* @see #readMapXml

* @see #readListXml

* @see #writeValueXml

public static final Object readValueXml(XmlPullParser parser, String[] name) throws XmlPullParserException, java.io.IOException {

int eventType = parser.getEventType();

do {

if (eventType == parser.START_TAG) {

return readThisValueXml(parser, name);

} else if (eventType == parser.END_TAG) {

throw new XmlPullParserException("Unexpected end tag at: " + parser.getName());

} else if (eventType == parser.TEXT) {

throw new XmlPullParserException("Unexpected text: " + parser.getText());

}

eventType = parser.next();

} while (eventType != parser.END_DOCUMENT);

throw new XmlPullParserException("Unexpected end of document");

}

private static final Object readThisValueXml(XmlPullParser parser, String[] name) throws XmlPullParserException, java.io.IOException {

final String valueName = parser.getAttributeValue(null, "name");

final String tagName = parser.getName();

// System.out.println("Reading this value tag: " + tagName + ", name=" +

// valueName);

Object res;

if (tagName.equals("null")) {

res = null;

} else if (tagName.equals("string")) {

String value = "";

int eventType;

while ((eventType = parser.next()) != parser.END_DOCUMENT) {

if (eventType == parser.END_TAG) {

if (parser.getName().equals("string")) {

name[0] = valueName;

// System.out.println("Returning value for " + valueName

// + ": " + value);

return value;

}

throw new XmlPullParserException("Unexpected end tag in <string>: " + parser.getName());

} else if (eventType == parser.TEXT) {

value += parser.getText();

} else if (eventType == parser.START_TAG) {

throw new XmlPullParserException("Unexpected start tag in <string>: " + parser.getName());

}

throw new XmlPullParserException("Unexpected end of document in <string>");

} else if (tagName.equals("int")) {

res = Integer.parseInt(parser.getAttributeValue(null, "value"));

} else if (tagName.equals("long")) {

res = Long.valueOf(parser.getAttributeValue(null, "value"));

} else if (tagName.equals("float")) {

res = new Float(parser.getAttributeValue(null, "value"));

} else if (tagName.equals("double")) {

res = new Double(parser.getAttributeValue(null, "value"));

} else if (tagName.equals("boolean")) {

res = Boolean.valueOf(parser.getAttributeValue(null, "value"));

} else if (tagName.equals("int-array")) {

parser.next();

res = readThisIntArrayXml(parser, "int-array", name);

name[0] = valueName;

// System.out.println("Returning value for " + valueName + ": " +

// res);

return res;

} else if (tagName.equals("map")) {

parser.next();

res = readThisMapXml(parser, "map", name);

name[0] = valueName;

// System.out.println("Returning value for " + valueName + ": " +

// res);

return res;

} else if (tagName.equals("list")) {

parser.next();

res = readThisListXml(parser, "list", name);

name[0] = valueName;

// System.out.println("Returning value for " + valueName + ": " +

// res);

return res;

} else {

throw new XmlPullParserException("Unknown tag: " + tagName);

}

// Skip through to end tag.

int eventType;

while ((eventType = parser.next()) != parser.END_DOCUMENT) {

if (eventType == parser.END_TAG) {

if (parser.getName().equals(tagName)) {

name[0] = valueName;

// System.out.println("Returning value for " + valueName +

// ": " + res);

return res;

}

throw new XmlPullParserException("Unexpected end tag in <" + tagName + ">: " + parser.getName());

} else if (eventType == parser.TEXT) {

throw new XmlPullParserException("Unexpected text in <" + tagName + ">: " + parser.getName());

} else if (eventType == parser.START_TAG) {

throw new XmlPullParserException("Unexpected start tag in <" + tagName + ">: " + parser.getName());

}

throw new XmlPullParserException("Unexpected end of document in <" + tagName + ">");

}

public static final void beginDocument(XmlPullParser parser, String firstElementName) throws XmlPullParserException, IOException {

int type;

while ((type = parser.next()) != parser.START_TAG && type != parser.END_DOCUMENT) {

;

}

if (type != parser.START_TAG) {

throw new XmlPullParserException("No start tag found");

}

if (!parser.getName().equals(firstElementName)) {

throw new XmlPullParserException("Unexpected start tag: found " + parser.getName() + ", expected " + firstElementName);

}

public static final void nextElement(XmlPullParser parser) throws XmlPullParserException, IOException {

int type;

while ((type = parser.next()) != parser.START_TAG && type != parser.END_DOCUMENT) {

;

}

3. MainActivity.java

package com.xml.demo;

import java.io.File;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.InputStream;

import java.util.ArrayList;

import java.util.List;

import org.xmlpull.v1.XmlSerializer;

import android.app.Activity;

import android.content.res.AssetManager;

import android.os.Bundle;

import android.util.Log;

import com.xml.demo.utils.FastXmlSerializer;

public class MainActivity extends Activity {

String TAG = "ZZMainActivity";

private AssetManager mAssetManager;

private InputStream mInputStream;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

mAssetManager = getApplicationContext().getAssets();

try {

mInputStream = mAssetManager.open("test.xml");

} catch (IOException e) {

e.printStackTrace();

}

testSaveXmlWithUtils();

}

private void testSaveXmlWithUtils() { // 生成xml文件

List<Person> persons = new ArrayList<Person>();

persons.add(new Person(80, "zhangsan", (short) 13));

persons.add(new Person(30, "wangwu", (short) 23));

persons.add(new Person(70, "zhaoliu", (short) 33));

try {

File file = new File(this.getFilesDir(), "toXmlFile.xml");

FileOutputStream str = new FileOutputStream(file);

XmlSerializer serializer = new FastXmlSerializer();

serializer.setOutput(str, "utf-8");

serializer.startDocument(null, true);

serializer.setFeature("http://xmlpull.org/v1/doc/features.html#indent-output", true);

serializer.startTag(null, "persons");

for (Person person : persons) {

serializer.startTag(null, "person");

serializer.attribute(null, "id", person.getId().toString());

serializer.startTag(null, "name");

serializer.text(person.getName());

serializer.endTag(null, "name");

serializer.startTag(null, "age");

serializer.text(person.getAge().toString());

serializer.endTag(null, "age");

serializer.endTag(null, "person");

}

serializer.endTag(null, "persons");

serializer.endDocument();

str.flush();

str.close();

} catch (IOException e) {

Log.w(TAG, "IOException:", e);

}

/data/data/com.xml.demo/files/toXmlFile.xml 文件：

<?xml version='1.0' encoding='utf-8' standalone='yes' ?>

<name>zhangsan</name>

</person>

<name>wangwu</name>

</person>

<name>zhaoliu</name>

</person>

</persons>

可以看到，通过上述工具类生成的xml文件，没有在同一行显示，比较格式化，看起来比较阅读。此时读取xml文件内容，可以参考 PullParserHandler类的getPersons()方法实现。

另外代码片段示例：

通过上述 FastXmlSerializer 生成xml文件，然后通过 Xml.newPullParser 读取xml文件

    private void writePreloadApkList(List<PreloadPackage> preloadApkList) {
        if (preloadApkList != null && preloadApkList.size() == 0) {
            Slog.d(TAG, "preload list size is 0");
            return;
        }

        FileOutputStream str = null;
        try {
            // TODO： delete it ?
            if (mPreloadListSaveFilePath != null && mPreloadListSaveFilePath.exists()) {
                Slog.d(TAG, "writePreloadList delete file");
                mPreloadListSaveFilePath.delete();
            }
            mPreloadListSaveFilePath = new File(mPreloadSaveFileDir.getPath() + mPreloadApkListFileName);

            str = new FileOutputStream(mPreloadListSaveFilePath);
            XmlSerializer serializer = new FastXmlSerializer();
            serializer.setOutput(str, "utf-8");
            serializer.startDocument(null, true);
            serializer.setFeature("http://xmlpull.org/v1/doc/features.html#indent-output", true);

            for (PreloadPackage preloadApp : preloadApkList) {
                serializer.startTag(null, "PackageItem");
                serializer.attribute(null, "packageName", preloadApp.packageName);
                serializer.attribute(null, "codePath", preloadApp.codePath);
                serializer.attribute(null, "originalCodePath", preloadApp.originalCodePath);
                serializer.endTag(null, "PackageItem");
            }
            serializer.endDocument();
            str.flush();
            str.close();
        } catch (IOException e) {
            Slog.e(TAG, "IOException:", e);
        } finally {
            if (str != null) {
                IoUtils.closeQuietly(str);
            }
        }
    }

    private List<PreloadPackage> readPreloadApkList() {
        mPreloadListSaveFilePath = new File(mPreloadSaveFileDir.getPath() + mPreloadApkListFileName);
        if (!mPreloadListSaveFilePath.exists()) {
            Slog.e(TAG, "preload file not exist");
            return new ArrayList<PreloadPackage>(); // Length is 0
        }

        FileInputStream str = null;
        try {
            str = new FileInputStream(mPreloadListSaveFilePath);
        } catch (FileNotFoundException e) {
            Slog.e(TAG, "read " + e);
        }

        List<PreloadPackage> preloadPackageList;
        PreloadPackage preloadPackage;
        try {
            preloadPackageList = new ArrayList<PreloadPackage>();
            XmlPullParser parser = Xml.newPullParser();
            parser.setInput(str, null);
            int type;
            int outerDepth = parser.getDepth();
            while ((type = parser.next()) != XmlPullParser.END_DOCUMENT && (type != XmlPullParser.END_TAG || parser.getDepth() > outerDepth)) {
                if (type == XmlPullParser.END_TAG || type == XmlPullParser.TEXT) {
                    continue;
                }
                String rootItem = parser.getName();
                String pkgName = parser.getAttributeValue(null, "packageName");
                String codePath = parser.getAttributeValue(null, "codePath");
                String originalCodePath = parser.getAttributeValue(null, "originalCodePath");
                String versionCode = parser.getAttributeValue(null, "versionCode");
                if (DBG)
                    Slog.d(TAG, "read preload  " + rootItem + " packageName:" + pkgName + " codePath:" + codePath + " versionCode:" + versionCode);

                if (!TextUtils.isEmpty(pkgName)) {
                    preloadPackage = new PreloadPackage();
                    preloadPackage.packageName = pkgName;
                    preloadPackage.codePath = codePath;
                    preloadPackage.originalCodePath = originalCodePath;
                    preloadPackageList.add(preloadPackage);
                }
            }
            return preloadPackageList;
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (XmlPullParserException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (str != null) {
                IoUtils.closeQuietly(str);
            }
        }
        return new ArrayList<PreloadPackage>(); // Length is 0
    }

五、SAX、DOM、Pull的比较

1. 内存占用：

SAX、Pull 优于DOM

2. 编程方式

好久不见

不滞于物，草木竹石均可为剑。自此精修，渐进于无剑胜有剑之境

Android SAX、DOM、Pull解析xml文件剖析与案例讲解（工具类FastXmlSerializer）

1. 工具类：FastXmlSerializer.java

2. 工具类：XmlUtils.java

通过上述 FastXmlSerializer 生成xml文件，然后通过 Xml.newPullParser 读取xml文件

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