jdom和dom4j的使用实例

用jdom对xml文件进行读写。

首先要下载一个jdom的jar包。再自己的项目中导入相应的jar包，其中包括builder目录下的jdom.jar，还是就是lib下面的jar包。。接下来就是操作了：（我的xml文件和class文件都放在了同一个目录下了）
1.xml文件实例：

<?xml version="1.0" encoding="UTF-8"?>
<school>
 <class name="class2">
  <student>
   <name>古天乐</name>
   <age>30</age>
   <score>59.3</score>
  </student>
  <student>
   <name>刘德华</name>
   <age>35</age>
   <score>59.6</score>
  </student>
 </class>
 <class name="class3">
  <student>
   <name>张学友</name>
   <age>36</age>
   <score>59.8</score>
  </student>
 </class>
</school>

2.对xml进行操作的java文件：

import java.io.IOException;
import java.util.List;

import org.jdom.Document;
import org.jdom.Element;
import org.jdom.JDOMException;
import org.jdom.input.SAXBuilder;


public class ReadXML4JDOM {

 public static void main(String[] args) {
  read("myschool.xml");
  System.out.println("执行完毕！");
 }
 
 public static void read(String filename) {
  SAXBuilder saxb = new SAXBuilder();
  try {
   Document dc = saxb.build(Thread.currentThread().getContextClassLoader().getResourceAsStream(filename));
   Element root = dc.getRootElement();
   List<Element> classes = (List) root.getChildren("class");
   for(Element element : classes) {
    String className = element.getAttributeValue("name");
    System.out.println(className+":");
    if(((List)element.getChildren("student")).size() == 1) {
     Element sudent = element.getChild("student");
     String name = sudent.getChildText("name");
     String age = sudent.getChildText("age");
     String score = sudent.getChildText("score");
     System.out.println("My name is "+name+",I'm "+age+" old! I'm in "+className+",and I got "+score+" scores!");
    }else {
     for(Element student : (List<Element>)element.getChildren("student")) {
      String name = student.getChildText("name");
      String age = student.getChildText("age");
      String score = student.getChildText("score");
      System.out.println("My name is "+name+",I'm "+age+" old! I'm in "+className+",and I got "+score+" scores!");
     }
    }
   }
  } catch (JDOMException e) {
   e.printStackTrace();
  } catch (IOException e) {
   e.printStackTrace();
  }
 }
}

3。运行结果：

class2:
My name is 古天乐,I'm 30 old! I'm in class2,and I got 59.3 scores!
My name is 刘德华,I'm 35 old! I'm in class2,and I got 59.6 scores!
class3:
My name is 张学友,I'm 36 old! I'm in class3,and I got 59.8 scores!
执行完毕！
---------------------------------------------------------
---------------------下面是dom4j---------------------------
----------------------------------------------------------
1.首先引入包。dom4j.jar，如果需要的话，还可以引入jaxen-。。-beta.jar

2.xml。和jdom的是一样的：

<?xml version="1.0" encoding="UTF-8"?>
<school>
 <class name="class2">
  <student>
   <name>古天乐</name>
   <age>30</age>
   <score>59.3</score>
  </student>
  <student>
   <name>刘德华</name>
   <age>35</age>
   <score>59.6</score>
  </student>
 </class>
 <class name="class3">
  <student>
   <name>张学友</name>
   <age>36</age>
   <score>59.8</score>
  </student>
 </class>
</school>

3.java代码：

import java.io.File;
import java.util.List;

import org.dom4j.Attribute;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;


public class ReadXML4Dom4j {

 public static void main(String[] args){
  read("src/myschool.xml");
 }

 public static void read(String filename) {
  SAXReader sr = new SAXReader();
  try {
   Document dc = sr.read(new File(filename));
   //获取根元素
   Element root = dc.getRootElement();
   for(Object obj : root.elements()) {
    Element myclass = (Element)obj;
    //获取某个标签的属性，首先获得标签的属性，然后再获取内容 
    Attribute ab = myclass.attribute("name");
    String classname = ab.getText();
    System.out.println(classname+":");
    //获取myclass标签下面的所有子元素
    List<Element> students = (List<Element>)myclass.elements(); 
    
    if(students.size() == 1) {
     Element student  = students.get(0);
     //获取name标签
     Element nameEle = student.element("name");
     //获取name标签的内容
     String name = nameEle.getText();
     
     Element ageEle = student.element("age");
     String age = ageEle.getText();
     
     Element scoreEle = student.element("score");
     String score = scoreEle.getText();
     
     System.out.println("name: "+name+",age: " +age+", score: "+score);
     
    }else {
     for(Element student : students) {
      Element nameEle = student.element("name");
      String name = nameEle.getText();
      
      Element ageEle = student.element("age");
      String age = ageEle.getText();
      
      Element scoreEle = student.element("score");
      String score = scoreEle.getText();
      System.out.println("name: "+name+",age: " +age+", score: "+score);
     }
    }
   }
  } catch (DocumentException e) {
   e.printStackTrace();
  }
 }
}