SAX解析Xml
解析步骤：
1、通过SAXParserFactory的静态newInstance()方法获取SAXParserFactory实例factory
SAXParserFactory factory = SAXParserFactory.newInstance();
2、通过SAXParserFactory实例的newSAXParser()方法返回SAXParser实例parser
SAXParser parser = factory.newSAXParser();
3、创建一个类继承DefaultHandler，重写其中的一些方法进行业务处理并创建这个类的实例handler
SAXParserHandler handler = new SAXParserHandler();
生成xml步骤：
1、创建一个TransformerFactory类的对象
SAXTransformerFactory tff = (SAXTransfromerFactory)SAXTransformerFactory.newInstance();
2、通过SAXTransformerFactory对象创建一个TransformerHandler对象
TransformerHandler handler = tff.newTransformerHandler();
3、通过handler对象创建一个Transformer对象
Transformer tr = handler.getTransformer();
4、通过Transformer对象生成的xml文件进行设置
//设置xml的编码 tr.setOutputProperty(OutputKeys.ENCODING,"UTF-8"); //设置xml是否换行 tr.setOutputProperty(OutputKeys.INDENT,"yes");
5、创建一个Result对象,并且使其与handler关联
File file = new File("book1.xml"); if(!file.exists()){ file.createNewFile(); } Result result = new StreamResult(new FileOutputStream(file)); handler.setResult(result);
6、利用handler对象进行xml文件内容的编写
需要解析的xml文件book.xml
<?xml version="1.0" encoding="UTF-8"?> <bookstore> <book id="1"> <name>冰与火之歌</name> <author>乔治马丁</author> <year>2014</year> <price>89</price> </book> <book id="2"> <name>安徒生童话</name> <year>2004</year> <price>77</price> <language>English</language> </book> </bookstore>
book.java
package com.imooc.entity; public class Book { private String id; private String name; private String author; private String year; private String price; private String language; public String getId() { return id; } public void setId(String id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getAuthor() { return author; } public void setAuthor(String author) { this.author = author; } public String getYear() { return year; } public void setYear(String year) { this.year = year; } public String getPrice() { return price; } public void setPrice(String price) { this.price = price; } public String getLanguage() { return language; } public void setLanguage(String language) { this.language = language; } }
SAXParserHandler.java
package com.imooc.handler; import java.util.ArrayList; import org.xml.sax.Attributes; import org.xml.sax.SAXException; import org.xml.sax.helpers.DefaultHandler; import com.imooc.entity.Book; public class SAXParserHandler extends DefaultHandler { String value = null; Book book = null; private ArrayList<Book> bookList = new ArrayList<Book>(); public ArrayList<Book> getBookList() { return bookList; } int bookIndex = 0; /** * 用来标识解析开始 */ @Override public void startDocument() throws SAXException { // TODO Auto-generated method stub super.startDocument(); System.out.println("SAX解析开始"); } /** * 用来标识解析结束 */ @Override public void endDocument() throws SAXException { // TODO Auto-generated method stub super.endDocument(); System.out.println("SAX解析结束"); } /** * 解析xml元素 */ @Override public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException { //调用DefaultHandler类的startElement方法 super.startElement(uri, localName, qName, attributes); if (qName.equals("book")) { bookIndex++; //创建一个book对象 book = new Book(); //开始解析book元素的属性 System.out.println("======================开始遍历某一本书的内容================="); // //已知book元素下属性的名称，根据属性名称获取属性值 // String value = attributes.getValue("id"); // System.out.println("book的属性值是：" + value); //不知道book元素下属性的名称以及个数，如何获取属性名以及属性值 int num = attributes.getLength(); for(int i = 0; i < num; i++){ System.out.print("book元素的第" + (i + 1) + "个属性名是：" + attributes.getQName(i)); System.out.println("---属性值是：" + attributes.getValue(i)); if (attributes.getQName(i).equals("id")) { book.setId(attributes.getValue(i)); } } } else if (!qName.equals("name") && !qName.equals("bookstore")) { System.out.print("节点名是：" + qName + "---"); } } @Override public void endElement(String uri, String localName, String qName) throws SAXException { //调用DefaultHandler类的endElement方法 super.endElement(uri, localName, qName); //判断是否针对一本书已经遍历结束 if (qName.equals("book")) { bookList.add(book); book = null; System.out.println("======================结束遍历某一本书的内容================="); } else if (qName.equals("name")) { book.setName(value); } else if (qName.equals("author")) { book.setAuthor(value); } else if (qName.equals("year")) { book.setYear(value); } else if (qName.equals("price")) { book.setPrice(value); } else if (qName.equals("language")) { book.setLanguage(value); } } @Override public void characters(char[] ch, int start, int length) throws SAXException { super.characters(ch, start, length); value = new String(ch, start, length); if (!value.trim().equals("")) { System.out.println("节点值是：" + value); } } }
SAXText.java
package com.imooc.test; import java.io.IOException; import javax.xml.parsers.ParserConfigurationException; import javax.xml.parsers.SAXParser; import javax.xml.parsers.SAXParserFactory; import org.xml.sax.SAXException; import org.xml.sax.SAXParseException; import com.imooc.entity.Book; import com.imooc.handler.SAXParserHandler; public class SAXTest { /** * @param args */ public static void main(String[] args) { //获取一个SAXParserFactory实例 SAXParserFactory factory = SAXParserFactory.newInstance(); //通过factory获取SAXParser实例 try { SAXParser parser = factory.newSAXParser(); //创建SAXParserHandler对象 SAXParserHandler handler = new SAXParserHandler(); parser.parse("books.xml", handler); System.out.println("~！~！~！共有" + handler.getBookList().size() + "本书"); for (Book book : handler.getBookList()) { System.out.println(book.getId()); System.out.println(book.getName()); System.out.println(book.getAuthor()); System.out.println(book.getYear()); System.out.println(book.getPrice()); System.out.println(book.getLanguage()); System.out.println("----finish----"); } } catch (ParserConfigurationException e) { e.printStackTrace(); } catch (SAXException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } }
