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：