使用PULL解析XML文件

XmlPull和Sax类似，是基于流（stream）操作文件，然后根据节点事件回调开发者编写的处理程序。因为是基于流的处理，因此Xmlpull和 Sax都比较节约内存资源，不会象Dom那样要把所有节点以对橡树的形式展现在内存中。 但Xmlpull比Sax更简明，而且不需要扫描完整个流。

下面来看一个pull解析xml的例子：

student.xml:

<?xml version="1.0" encoding="utf-8"?>  
    <root>  
        <student id="1" group="1">  
            <name>张三</name>  
            <sex>男</sex>  
            <age>18</age>  
            <email>zhangsan@163.com</email>  
            <birthday>1987-06-08</birthday>  
            <memo>好学生</memo>  
        </student>  
        <student id="2" group="2">  
            <name>李四</name>  
            <sex>女</sex>  
            <age>18</age>  
            <email>lisi@163.com</email>  
            <birthday>1987-06-08</birthday>  
            <memo>好学生</memo>  
        </student>  
        <student id="3" group="3">  
            <name>小王</name>  
            <sex>男</sex>  
            <age>18</age>  
            <email>xiaowang@163.com</email>  
            <birthday>1987-06-08</birthday>  
            <memo>好学生</memo>  
        </student>  
        <student id="4" group="4">  
            <name>小张</name>  
            <sex>男</sex>  
            <age>18</age>  
            <email>xiaozhang@163.com</email>  
            <birthday>1987-06-08</birthday>  
            <memo>好学生</memo>  
        </student>  
        <student id="5" group="5">  
            <name>小明</name>  
            <sex>男</sex>  
            <age>18</age>  
            <email>xiaoming@163.com</email>  
            <birthday>1987-06-08</birthday>  
            <memo>好学生</memo>  
        </student>  
    </root>

对应的bean：

public class Student {  
    
    private int id;  
    private int group;  
    private String name;  
    private String sex;  
    private int age;  
    private String email;  
    private String memo;  
    private String birthday;  
    public int getId() {  
        return id;  
    }  
    public void setId(int id) {  
        this.id = id;  
    }  
    public int getGroup() {  
        return group;  
    }  
    public void setGroup(int group) {  
        this.group = group;  
    }  
    public String getName() {  
        return name;  
    }  
    public void setName(String name) {  
        this.name = name;  
    }  
    public String getSex() {  
        return sex;  
    }  
    public void setSex(String sex) {  
        this.sex = sex;  
    }  
    public int getAge() {  
        return age;  
    }  
    public void setAge(int age) {  
        this.age = age;  
    }  
    public String getEmail() {  
        return email;  
    }  
    public void setEmail(String email) {  
        this.email = email;  
    }  
    public String getMemo() {  
        return memo;  
    }  
    public void setMemo(String memo) {  
        this.memo = memo;  
    }  
    public String getBirthday() {  
        return birthday;  
    }  
    public void setBirthday(String birthday) {  
        this.birthday = birthday;  
    }  
      
}

主要的解析和现实类：

import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserFactory;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.view.ViewGroup.LayoutParams;
import android.widget.LinearLayout;

import android.widget.TextView;

public class PullActivity extends Activity implements Runnable{

	private TextView pullTextView ;
	private LinearLayout layout;
	private Handler handler=new Handler(){
		 public void handleMessage(android.os.Message msg) {
			 List<Student> lists=(List<Student>) msg.obj;
			 for(int i=0;i<lists.size();i++){
				 Student student=lists.get(i);
				 StringBuffer sb=new StringBuffer();
				 sb.append(student.getId()+"  ").append(student.getName()+"  ")
				 .append(student.getAge()+"  ").append(student.getSex()+" ").append(student.getBirthday()+"  ")
				 .append(student.getEmail()+"  ").append(student.getGroup()+"  ");
				 TextView txt=new TextView(getApplicationContext());
				 txt.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
				 txt.setText(sb.toString());
				 layout.addView(txt);
			 }
		 };
	};
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		// TODO Auto-generated method stub
		super.onCreate(savedInstanceState);
		setContentView(R.layout.pull);
		
		pullTextView=(TextView) this.findViewById(R.id.pullTextView);
		layout=(LinearLayout) this.findViewById(R.id.layout);
		new Thread(this).start();
		
		 
		 
	}
	//pull解析xml
	public List<Student> pullParseXml(){
		List<Student> lists=null;
		Student student=null;
		
		try {
			XmlPullParserFactory factory=XmlPullParserFactory.newInstance();
			//获取XmlPullParser实例
			XmlPullParser pullParser=factory.newPullParser();
			InputStream in=this.getClass().getClassLoader().getResourceAsStream("student.xml");
			pullParser.setInput(in, "UTF-8");
			//开始
			int eventType=pullParser.getEventType();
			
			while(eventType!=XmlPullParser.END_DOCUMENT){
				String nodeName=pullParser.getName();
				switch (eventType) {
				//文档开始
				case XmlPullParser.START_DOCUMENT:
					 lists=new ArrayList<Student>();
					break;

					//开始节点
				case XmlPullParser.START_TAG:
					if("student".equals(nodeName)){
						student=new Student();
						student.setId(Integer.parseInt(pullParser.getAttributeValue(0)));
						student.setGroup(Integer.parseInt(pullParser.getAttributeValue(1)));
					}else if("name".equals(nodeName)){
						student.setName(pullParser.nextText());
					}else if("sex".equals(nodeName)){
						student.setSex(pullParser.nextText());
					}else if("age".equals(nodeName)){
						student.setAge(Integer.parseInt(pullParser.nextText()));
					}else if("email".equals(nodeName)){
						student.setEmail(pullParser.nextText());
					}else if("birthday".equals(nodeName)){
						student.setBirthday(pullParser.nextText());
					}else if("memo".equals(nodeName)){
						student.setMemo(pullParser.nextText());
					}
					break;
					//结束节点
				case XmlPullParser.END_TAG:
					if("student".equals(nodeName)){
						lists.add(student);
						student=null;
					}
					break;
				default:
					break;
				}
				 // 手动的触发下一个事件  
				eventType=pullParser.next();
			}
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return lists;
		
	}
	@Override
	public void run() {
		// TODO Auto-generated method stub
		List<Student> lists=pullParseXml();
		Message msg=handler.obtainMessage();
		msg.obj=lists;
		handler.sendMessage(msg);
	}
}

注意xml中的<?xml version="1.0" encoding="utf-8"?> 这句话要顶格显示，不要留空隙，附则错了很难调试的。

解析后效果：