一. 前言

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//创建SAXParser工厂
SAXParserFactory saxParserFactory = SAXParserFactory.newInstance();
//通过SAXParser工厂创建SAXParser
SAXParser saxParser = saxParserFactory.newSAXParser();
//通过SAXParser获取XMLReader
XMLReader xmlReader = saxParser.getXMLReader();

//实例化自己继承于DefaultHandler的SAXParseHandler，并将其设置为XMLReader的ContentHandler
SAXParseHandler saxParseHandler = new SAXParseHandler();
xmlReader.setContentHandler(saxParseHandler);

//获取xml数据流，并将其转化为InputSource
InputStream is = getResources().openRawResource(R.raw.test);
InputSource inputSource = new InputSource(is);

//使用xmlReader解析Xml文件
xmlReader.parse(inputSource);
saxParseHandler.getXmlList();

二. DefaultHandler重写方法的执行顺序

1. 继承 DefaultHandler 的类

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public class SAXParseHandler extends DefaultHandler {

    //日志
    public static final String TAG = SAXParseHandler.class.getSimpleName();

    //解析的数据集合
    private List<WebItem> webItems;

    //子项的name
    private String ITEM = "item";
    private WebItem webItem;

    //开始这个文件 test.xml
    @Override
    public void startDocument() throws SAXException {
        super.startDocument();
        Log.d(TAG,"startDocument");

        webItems = new ArrayList<>();
    }

    //开始这个元素 item
    @Override
    public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
        super.startElement(uri, localName, qName, attributes);
        Log.d(TAG,"startElement localName:"+localName+" qName:"+qName);

        //new 一个模型类
        webItem = new WebItem();

        //如果元素名相同
        if (TextUtils.equals(localName, ITEM)){
            for (int i = 0; i < attributes.getLength(); i++) {
                //循环读取属性 id
                if (TextUtils.equals(attributes.getLocalName(i),"id")){
                    webItem.setId(Integer.parseInt(attributes.getValue(i)));
                }

                //循环读取属性 url
                if (TextUtils.equals(attributes.getLocalName(i),"url")){
                    webItem.setUrl(attributes.getValue(i));
                }
            }
        }
    }

    //内容 百度
    @Override
    public void characters(char[] ch, int start, int length) throws SAXException {
        super.characters(ch, start, length);

        //获取内容
        String content = String.valueOf(ch, start, length);
        Log.d(TAG,"characters ch:"+content);
    }

    //结束这个元素 item
    @Override
    public void endElement(String uri, String localName, String qName) throws SAXException {
        super.endElement(uri, localName, qName);
        Log.d(TAG,"endElement localName:"+localName+" qName:"+qName);

        webItems.add(webItem);
    }

    //结束这个文件 test.xml
    @Override
    public void endDocument() throws SAXException {
        super.endDocument();
        Log.d(TAG,"endDocument");
    }

    //返回数据
    public List<WebItem> getXmlList(){
        return webItems;
    }
}

2. 根据xml文件的内容将方法执行顺序输入到日志中

① 只有一个根节点

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//待解析的Xml文件
<?xml version="1.0" encoding="utf-8"?>
<web></web>
  
//解析结果
startDocument
startElement localName:web qName:web
characters ch:
characters ch:

characters ch:
endElement localName:web qName:web 
endDocument

② 根节点下有一个非根节点

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//待解析的Xml文件
<?xml version="1.0" encoding="utf-8"?>
<web>
    <item id="0" url="https://www.baidu.com">百度</item>
</web>

//解析结果
startDocument
startElement localName:web qName:web
characters ch:
characters ch:

startElement localName:item qName:item
characters ch:百度
endElement localName:item qName:item
characters ch:
characters ch:

characters ch:
endElement localName:web qName:web
endDocument

③ 根节点下有两个非根节点

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//待解析的Xml文件
<?xml version="1.0" encoding="utf-8"?>
<web>
    <item id="0" url="https://www.baidu.com">百度</item>
    <item id="1" url="https://www.taobao.com">淘宝</item>
</web>

//解析结果
startDocument
startElement localName:web qName:web
characters ch:
characters ch:

startElement localName:item qName:item
characters ch:百度
endElement localName:item qName:item
characters ch:
characters ch:

startElement localName:item qName:item
characters ch:淘宝
endElement localName:item qName:item
characters ch:
characters ch:

characters ch:
endElement localName:web qName:web
endDocument

④ 根节点下有三个非根节点

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//待解析的Xml文件
<?xml version="1.0" encoding="utf-8"?>
<web>
    <item id="0" url="https://www.baidu.com">百度</item>
    <item id="1" url="https://www.taobao.com">淘宝</item>
    <item id="2" url="https://www.qq.com">腾讯</item>
</web>

//解析结果
startDocument
startElement localName:web qName:web
characters ch:
characters ch:

startElement localName:item qName:item
characters ch:百度
endElement localName:item qName:item
characters ch:
characters ch:

startElement localName:item qName:item
characters ch:淘宝
endElement localName:item qName:item
characters ch:
characters ch:

startElement localName:item qName:item
characters ch:腾讯
endElement localName:item qName:item

characters ch:
endElement localName:web qName:web
endDocument

⑤ 根节点下有四个非根节点

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//待解析的Xml文件
<?xml version="1.0" encoding="utf-8"?>
<web>
    <item id="0" url="https://www.baidu.com">百度</item>
    <item id="1" url="https://www.taobao.com">淘宝</item>
    <item id="2" url="https://www.qq.com">腾讯</item>
    <item id="3" url="https://www.aili.com">阿里巴巴</item>
</web>

//解析结果  
startDocument
startElement localName:web qName:web
characters ch:
characters ch:

startElement localName:item qName:item
characters ch:百度
endElement localName:item qName:item
characters ch:
characters ch:

startElement localName:item qName:item
characters ch:淘宝
endElement localName:item qName:item
characters ch:
characters ch:

startElement localName:item qName:item
characters ch:腾讯
endElement localName:item qName:item
characters ch:
characters ch:

startElement localName:item qName:item
characters ch:阿里巴巴
endElement localName:item qName:item

characters ch:
endElement localName:web qName:web
endDocument

⑥ 总结规律

如果是根节点，那么一定会执行以下的方法：

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startDocument
startElement localName:web qName:web
characters ch:
characters ch:

characters ch:
endElement localName:web qName:web 
endDocument

如果是非根节点，且根节点下的非根节点数 <= 两个，对于非根节点一定会执行以下的方法：

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startElement localName:item qName:item
characters ch:内容值
endElement localName:item qName:item
characters ch:
characters ch:

如果是非根节点，且根节点下的非根节点数 > 两个，对于非根节点一定会执行以下的方法：

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//最后一个根节点执行：
startElement localName:item qName:item
characters ch:内容值
endElement localName:item qName:item
  
//其他根节点执行：
startElement localName:item qName:item
characters ch:内容值
endElement localName:item qName:item
characters ch:
characters ch:

三. 实际小例子

1. 继承于DefaultHandler的SAXParseHandler

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public class SAXParseHandler extends DefaultHandler {

    //日志
    public static final String TAG = SAXParseHandler.class.getSimpleName();

    //解析的数据集合
    private List<WebItem> webItems;

    //子项的name
    private String NODE_NAME = "item";

    //模型类
    private WebItem webItem;

    //当前读取的node_name的值
    private String current_node_name;

    //开始这个文件 test.xml
    @Override
    public void startDocument() throws SAXException {
        super.startDocument();
        Log.d(TAG,"startDocument");

        webItems = new ArrayList<>();
    }

    //开始这个元素 item
    @Override
    public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
        super.startElement(uri, localName, qName, attributes);
        Log.d(TAG,"startElement localName:"+localName+" qName:"+qName);

        //new 一个模型类
        webItem = new WebItem();

        //如果元素名相同
        if (TextUtils.equals(localName, NODE_NAME)){
            //设置当前的node_name
            current_node_name = localName;

            //读取属性
            for (int i = 0; i < attributes.getLength(); i++) {
                //循环读取属性 id
                if (TextUtils.equals(attributes.getLocalName(i),"id")){
                    webItem.setId(Integer.parseInt(attributes.getValue(i)));
                }

                //循环读取属性 url
                if (TextUtils.equals(attributes.getLocalName(i),"url")){
                    webItem.setUrl(attributes.getValue(i));
                }
            }
        }
    }

    //内容 百度
    @Override
    public void characters(char[] ch, int start, int length) throws SAXException {
        super.characters(ch, start, length);

        //获取内容
        String content = String.valueOf(ch, start, length);
        Log.d(TAG,"characters ch:"+content);

        //设置
        if (TextUtils.equals(current_node_name,NODE_NAME)){
            webItem.setContent(content);
        }
    }

    //结束这个元素 item
    @Override
    public void endElement(String uri, String localName, String qName) throws SAXException {
        super.endElement(uri, localName, qName);
        Log.d(TAG,"endElement localName:"+localName+" qName:"+qName);

        if (TextUtils.equals(current_node_name,NODE_NAME)){
            //将读取的数据加入到集合中
            webItems.add(webItem);
        }

        //取消当前的node_name
        current_node_name = null;
    }

    //结束这个文件 test.xml
    @Override
    public void endDocument() throws SAXException {
        super.endDocument();
        Log.d(TAG,"endDocument");
    }

    //返回数据
    public List<WebItem> getXmlList(){
        return webItems;
    }
}

2. 待解析的Xml文件

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<?xml version="1.0" encoding="utf-8"?>
<web>
    <item id="0" url="https://www.baidu.com">百度</item>
    <item id="1" url="https://www.taobao.com">淘宝</item>
    <item id="2" url="https://www.qq.com">腾讯</item>
    <item id="3" url="https://www.aili.com">阿里巴巴</item>
    <item id="4" url="https://www.taobao.com">淘宝</item>
    <item id="5" url="https://www.wechat.com">微信</item>
    <item id="6" url="https://www.timi.com">天美</item>
    <item id="7" url="https://www.guangzi.com">光子</item>
    <item id="8" url="https://www.taoken.com">字节跳动</item>
    <item id="9" url="https://www.douyin.com">抖音</item>
</web>

3. Activity中的调用

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public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        try {
            //解析Xml数据
            testSexParse();
        } catch (ParserConfigurationException e) {
            e.printStackTrace();
        } catch (SAXException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * Sex方式解析
     */
    private void testSexParse() throws ParserConfigurationException, SAXException, IOException {
        /*SAXParserFactory saxParserFactory = SAXParserFactory.newInstance();
        SAXParser saxParser = saxParserFactory.newSAXParser();
        XMLReader xmlReader = saxParser.getXMLReader();

        SAXParseHandler saxParseHandler = new SAXParseHandler();
        xmlReader.setContentHandler(saxParseHandler);

        InputStream is = getResources().openRawResource(R.raw.test);
        InputSource inputSource = new InputSource(is);

        xmlReader.parse(inputSource);
        saxParseHandler.getXmlList();*/

        XMLReader xmlReader = SAXParserFactory.newInstance().newSAXParser().getXMLReader();
        xmlReader.setContentHandler(new SAXParseHandler());
        xmlReader.parse(new InputSource(getResources().openRawResource(R.raw.test)));

        SAXParseHandler saxParseHandler = (SAXParseHandler) xmlReader.getContentHandler();
        for (WebItem webItem : saxParseHandler.getXmlList()) {
            //Toast.makeText(this, "id:"+webItem.getId()+" url:"+webItem.getUrl()+" content:"+webItem.getContent(), Toast.LENGTH_SHORT).show();
            //显示数据
            addToRootLayout((LinearLayout) findViewById(R.id.root),webItem);
        }
    }

    /**
     * 将WebItem显示到布局中
     * @param layout
     * @param webItem
     */
    private void addToRootLayout(LinearLayout layout, WebItem webItem){
        View inflate = LayoutInflater.from(this).inflate(R.layout.web_item_layout, null);
        TextView id_text = inflate.findViewById(R.id.id);
        TextView content_text = inflate.findViewById(R.id.content);
        TextView url_text = inflate.findViewById(R.id.url);

        id_text.setText(String.valueOf(webItem.getId()));
        content_text.setText(webItem.getContent());
        url_text.setText(webItem.getUrl());

        layout.addView(inflate);
    }
}

4. 运行结果

5. 源码地址

ParseXml

参考文章

sax中DefaultHander解析xml过程和先后顺序