【JAVA UI】【HarmonyOS】【Demo】鸿蒙如何进行xml解析

【鸿蒙】鸿蒙如何进行数据解析

【问题描述】有时候我们从服务器获取是xml格式数据，我们需要将xml转化成model对象，该如何使用呢？下面举个例子说明一下，将分以下几步进行

1. 准备条件创建xml文件，创建model对象，构建界面

2. 数据进行解析操作（重点）

3. 运行效果

第一步准备条件创建xml文件，创建model对象，构建界面

1.1在rawfile 新建xml文件，代码如下

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

<note>

    <to>George</to>

    <from>John</from>

    <heading>Reminder</heading>

    <body>Don't forget the meeting!</body>

</note>

1.2新建class model代码如下

package com.harmony.alliance.mydemo.model;

 

public class note {

    private  String from;

    private  String heading;

    private String body;

    private  String to;

 

    public String getFrom() {

        return from;

    }

 

    public void setFrom(String from) {

        this.from = from;

    }

 

    public String getBody() {

        return body;

    }

 

    public void setBody(String body) {

        this.body = body;

    }

 

    public String getTo() {

        return to;

    }

 

    public void setTo(String to) {

        this.to = to;

    }

 

    public String getHeading() {

        return heading;

    }

 

    public void setHeading(String heading) {

        this.heading = heading;

    }

 

    @Override

    public String toString() {

        return "note{" +

                "from='" + from + '\'' +

                ", heading='" + heading + '\'' +

                ", body='" + body + '\'' +

                ", to='" + to + '\'' +

                '}';

    }

}

1.3新建数据的abilityslice，xml如下

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

<DirectionalLayout

    xmlns:ohos="http://schemas.huawei.com/res/ohos"

    ohos:height="match_parent"

    ohos:width="match_parent"

    ohos:orientation="vertical">

    <Text

        ohos:id="$+id:mStartParse"

        ohos:height="100vp"

        ohos:width="match_parent"

        ohos:text="开始解析"

        ohos:text_size="20fp"

        ohos:text_color="#ffffff"

        ohos:text_alignment="center"

        ohos:background_element="#ed6262"/>

    <Text

        ohos:id="$+id:mTo"

        ohos:height="100fp"

        ohos:width="match_parent"

        ohos:text_size="20fp"

        ohos:text_color="#ed6262"

        ohos:background_element="#ffffff"/>

    <Text

        ohos:id="$+id:mfrom"

        ohos:height="100fp"

        ohos:width="match_parent"

        ohos:text_size="20fp"

        ohos:text_color="#ed6262"

        ohos:background_element="#ffffff"/>

    <Text

        ohos:id="$+id:mheading"

        ohos:height="100fp"

        ohos:width="match_parent"

        ohos:text_size="20fp"

        ohos:text_color="#ed6262"

        ohos:background_element="#ffffff"/>

 

    <Text

        ohos:id="$+id:mbody"

        ohos:height="100fp"

        ohos:width="match_parent"

        ohos:text_size="20fp"

        ohos:text_color="#ed6262"

        ohos:background_element="#ffffff"/>

 

</DirectionalLayout>

界面效果如下

第二步数据解析

2.1参考资料如下

SAXParser

https://developer.harmonyos.com/cn/docs/documentation/doc-references/saxparser-0000001060039145

XMLReader

https://developer.harmonyos.com/cn/docs/documentation/doc-references/xmlreader-0000001060837300

该功能和Android的demo相似可以参考Android的demo链接

https://blog.csdn.net/bzlj2912009596/article/details/80262191

在上述四个接口中，最重要的就是ContentHandler这个接口，下面是对这个接口方法的说明：

//设置一个可以定位文档内容事件发生位置的定位器对象

public void setDocumentLocator(Locator locator)

//用于处理文档解析开始事件

public void startDocument()throws SAXException

//处理元素开始事件，从参数中可以获得元素所在名称空间的uri，元素名称，属性类表等信息

public void startElement(String namespacesURI , String localName , String qName , Attributes atts) throws SAXException

//处理元素结束事件，从参数中可以获得元素所在名称空间的uri，元素名称等信息

public void endElement(String namespacesURI , String localName , String qName) throws SAXException

//处理元素的字符内容，从参数中可以获得内容

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

新建SaxHelper代码如下

package com.harmony.alliance.mydemo.model;

 

import ohos.org.xml.sax.Attributes;

import ohos.org.xml.sax.SAXException;

import ohos.org.xml.sax.helpers.DefaultHandler;

 

/**

 * Created by Jay on 2015/9/8 0008.

 */

public class SaxHelper extends DefaultHandler {

    //当前解析的元素标签

    private String tagName = null;

    private  note mNote;

 

    /**

     * 当读取到文档开始标志是触发，通常在这里完成一些初始化操作

     */

    @Override

    public void startDocument() throws SAXException {

        mNote=new note();

    }

 

    /**

     * 读到一个开始标签时调用,第二个参数为标签名,最后一个参数为属性数组

     */

    @Override

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

        System.err.println("####===>>"+localName);

        this.tagName = localName;

    }

 

    /**

     * 读到到内容,第一个参数为字符串内容,后面依次为起始位置与长度

     */

 

    @Override

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

        //判断当前标签是否有效

        if (this.tagName != null) {

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

            //读取标签中的内容

            if (this.tagName.equals("to")) {

                mNote.setTo(data);

            } else if (this.tagName.equals("from")) {

                mNote.setFrom(data);

            }else  if(this.tagName.equals("heading")){

                mNote.setHeading(data);

            }else  if(this.tagName.equals("body")){

                mNote.setBody(data);

            }

 

        }

 

    }

 

    /**

     * 处理元素结束时触发,这里将对象添加到结合中

     */

    @Override

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

        this.tagName = null;

    }

 

    /**

     * 读取到文档结尾时触发，

     */

    @Override

    public void endDocument() throws SAXException {

        super.endDocument();

        System.err.println("#####===>>"+mNote.toString());

//        Log.i("SAX", "读取到文档尾,xml解析结束");

    }

    public note getmNote() {

        return mNote;

    }

 

}

AbilitySlice代码如下

package com.harmony.alliance.mydemo.slice;

 

import com.harmony.alliance.mydemo.ResourceTable;

import com.harmony.alliance.mydemo.model.SaxHelper;

import com.harmony.alliance.mydemo.model.note;

import ohos.aafwk.ability.AbilitySlice;

import ohos.aafwk.content.Intent;

import ohos.agp.components.Component;

import ohos.agp.components.Text;

import ohos.javax.xml.parsers.SAXParser;

import ohos.javax.xml.parsers.SAXParserFactory;

import ohos.org.xml.sax.InputSource;

import ohos.org.xml.sax.XMLReader;

import java.io.InputStream;

import java.util.Locale;

 

public class myXmlParseAbilitySlice extends AbilitySlice {

    private Text mStartParse,mTo,mfrom,mheading,mbody;

    @Override

    protected void onStart(Intent intent) {

        super.onStart(intent);

        setUIContent(ResourceTable.Layout_my_xml_parse);

        mStartParse= (Text) findComponentById(ResourceTable.Id_mStartParse);

        mTo= (Text) findComponentById(ResourceTable.Id_mTo);

        mfrom= (Text) findComponentById(ResourceTable.Id_mfrom);

        mheading= (Text) findComponentById(ResourceTable.Id_mheading);

        mbody= (Text) findComponentById(ResourceTable.Id_mbody);

        mStartParse.setClickedListener(new Component.ClickedListener() {

            @Override

            public void onClick(Component component) {

                try {

                    String rawFilePath = "note.xml";

                    String filePath = String.format(Locale.ROOT, "assets/entry/resources/rawfile/%s", rawFilePath);

                    InputStream     is = this.getClass().getClassLoader().getResourceAsStream(filePath);

                    InputSource is2=new InputSource(is);

                    SaxHelper ss = new SaxHelper();

                    SAXParserFactory factory = SAXParserFactory.newInstance();

                    factory.setNamespaceAware(true);

                    SAXParser parser = factory.newSAXParser();

                    XMLReader xmlReader=parser.getXMLReader();

                    xmlReader.setContentHandler(ss);

                    xmlReader.parse(is2);

                    note mNote= ss.getmNote();

                    mTo.setText("to: "+mNote.getTo());

                    mfrom.setText("From:  "+mNote.getFrom());

                    mheading.setText("heading:  "+mNote.getHeading());

                    mbody.setText("body:  "+mNote.getBody());

                    is.close();

                }catch (Exception e){

                    e.printStackTrace();

                }

            }

        });

    }

}

第三步运行效果如下

posted @ 2022-07-08 10:30 华为开发者论坛阅读(250) 评论(0) 编辑收藏举报

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【JAVA UI】【HarmonyOS】【Demo】 鸿蒙如何进行xml解析

第一步准备条件 创建xml文件，创建model对象，构建界面