《第一行代码》笔记(10)—XML的SAX解析

package com.zjw.mynetwork5;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

import org.xml.sax.InputSource;
import org.xml.sax.XMLReader;

import java.io.IOException;
import java.io.StringReader;

import javax.xml.parsers.SAXParserFactory;

import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;

//9.3.2 p326 SAX解析方式
//新建一个类继承DefaultHandler,重写父类5个方法
/*
重写父类5个方法:
1.startDocument()会在开始XML解析时调用
2.startElement()会在开始解析某个节点的时候调用
3.characters()会在获取节点中内容时调用
4.endElement()会在完成某个节点时调用
5.endDocument()会在完成整个XML解析时调用
其中2,3,4有参数，3可能被调用多次，要处理好换行符
 */
//之前Pull解析代码拷一份过来(笔记(9))，进行修改主要是parseXMLWithSAX()方法
public class SAXAnalysisOfXML extends AppCompatActivity {
    private Button mBtnSendRequest;
    private TextView mTvResponseText;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_saxanalysis_of_xml);
        //找到控件
        mBtnSendRequest = (Button) findViewById(R.id.btn_send_request);
        mTvResponseText = (TextView) findViewById(R.id.tv_response_text);

        //Button点击事件，发送HTTP请求
        mBtnSendRequest.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //用OkHttp发送HTTP请求
                sendRequestWithOkHttp();
            }
        });
    }

    private void sendRequestWithOkHttp() {
        //开启新线程做耗时操作
        new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    OkHttpClient client = new OkHttpClient();//创建一个OkHttpClient实例
                    Request request = new Request.Builder()
                            .url("http://10.0.2.2:8080/get_data.xml")//设置目标网络地址
                            .build();//创建一个Request对象
                    Response response = client.newCall(request).execute();//发送请求获取服务器返回对象
                    String responseData = response.body().string();

                    //解析XML
                    parseXMLWithSAX(responseData);
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }).start();
    }

    private void parseXMLWithSAX(String responseData) {
        StringBuilder builder = new StringBuilder();

        try {
            SAXParserFactory saxParserFactory = SAXParserFactory.newInstance();//创建工厂
            XMLReader xmlReader = saxParserFactory.newSAXParser().getXMLReader();//创建XMLReader实例
            MyHandler handler = new MyHandler();//获取handle
            xmlReader.setContentHandler(handler);//设置handle
            xmlReader.parse(new InputSource(new StringReader(responseData)));//开始解析
            showResponse(handler.getString());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    //将数据设置给TextView
    private void showResponse(final String s) {
        //在UI线程(主线程)更新UI,因为Android不允许在子线程中进行UI操作
        runOnUiThread(new Runnable() {
            @Override
            public void run() {
                mTvResponseText.setText(s);
            }
        });
    }
}

package com.zjw.mynetwork5;

import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;

/**
 * Created by hp on 2017/7/26.
 */

public class MyHandler extends DefaultHandler {

    private String nodeName;
    private StringBuilder id;
    private StringBuilder name;
    private StringBuilder version;
    StringBuilder builder = new StringBuilder();

    //会在开始XML解析时调用
    @Override
    public void startDocument() throws SAXException {
        id = new StringBuilder();
        name = new StringBuilder();
        version = new StringBuilder();
    }

    //会在开始解析某个节点的时候调用
    @Override
    public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
        nodeName = localName;//记录当前节点名
    }

    //会在获取节点中内容时调用
    @Override
    public void characters(char[] ch, int start, int length) throws SAXException {
        //根据当前的节点名判断将内容添加到哪一个StringBuilder对象中
        if ("id".equals(nodeName)) {
            id.append(ch, start, length);
        } else if ("name".equals(nodeName)) {
            name.append(ch, start, length);
        } else if ("version".equals(nodeName)) {
            version.append(ch, start, length);
        }
    }

    //会在完成某个节点时调用
    @Override
    public void endElement(String uri, String localName, String qName) throws SAXException {
        if ("app".equals(localName)) {
            builder.append("id:" + id.toString().trim() + "\n")
                    .append("name:" + name.toString().trim() + "\n")
                    .append("version:" + version.toString().trim() + "\n")
                    .append("-----------------------------\n");
            //清空
            id.setLength(0);
            name.setLength(0);
            version.setLength(0);
        }
    }

    //会在完成整个XML解析时调用
    @Override
    public void endDocument() throws SAXException {
        super.endDocument();
    }

    public String getString(){
        return builder.toString();
    }
}

转载于:https://my.oschina.net/u/3620480/blog/1489796