dom4j学习笔记

一、生成xml文件
1. 下载dom4j-1.6.1.jar和jaxen-1.1-beta-10.jar，下载地址分别如下：
        http://

        http://jaxen.codehaus.org/releases.html


注：本文附带的源码中有以上两个JAR文件。

2. 写一个批处理文件dom4j.bat，内容如下：

set CLASSPATH=c:\test\jar\jaxen-1.1-beta-10.jar;c:\test\jar\dom4j-1.6.1.jar;%CLASSPATH%


3. 编写代码(编译前运行一下dom4j.bat),成功运行后会在cmd内显示生成的xml文件的内容，而且在C盘下会生成“output.xml”文件。大部分代码摘自官方网站的quick start，我做了些修正，因为官方的不能直接运行。代码如下：

import org.dom4j.Document;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.XMLWriter;
import java.io.IOException;
import java.io.FileWriter;

public class CreateXML {

  // 输出XML数据

  public void write(Document document) throws IOException {

   // xml 标准格式，保存到文件

   OutputFormat format = OutputFormat.createPrettyPrint();
   XMLWriter writer = new XMLWriter(new FileWriter( "c:\\output.xml" ), format );
   writer.write( document );
   writer.close();

   // 紧凑的格式，System.out显示(

   format = OutputFormat.createCompactFormat();
   writer = new XMLWriter( System.out, format );
   System.out.println("\r\n------------------Start------------------");
   writer.write( document );
   System.out.println("\r\n-------------------End-------------------");
   writer.close();

  }

  // 返回XML对象

  public Document createDocument() {
   Document document = DocumentHelper.createDocument();
   Element root = document.addElement( "root" );

   Element author1 = root.addElement( "author" )
    .addAttribute( "name", "James" )
    .addAttribute( "location", "UK" )
    .addText( "James Strachan" );
   
   Element author2 = root.addElement( "author" )
    .addAttribute( "name", "Bob" )
    .addAttribute( "location", "US" )
    .addText( "Bob McWhirter" );

   return document;
  }

  public static void main(String[] args) {
   CreateXML dom4j = new CreateXML();
   try {
    dom4j.write(dom4j.createDocument());

   } catch (IOException e) {
    System.out.println(e.getMessage());
   }
  }
}

4. 运行过程和结果：

C:\test>dom4j.bat

C:\test>set CLASSPATH=c:\test\jar\jaxen-1.1-beta-10.jar;c:\test\jar\dom4j-1.6.1.
jar;.;c:\jdk1.5\lib

C:\test>javac CreateXML.java

C:\test>java CreateXML

------------------Start------------------
<?xml version="1.0" encoding="UTF-8"?>
<root><author name="James" location="UK">James Strachan</author><author name="Bob" location="US">Bob McWhirter</author></root>
-------------------End-------------------

C:\test>

二、获取XML文件中的数据

代码如下：

import java.net.URL;
import java.io.IOException;
import java.io.FileWriter;
import java.io.File;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.XMLWriter;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.io.SAXReader;

public class Parse_1 {

    public Document parse(String sfile) throws DocumentException {
        SAXReader reader = new SAXReader();
        Document document = reader.read(new File(sfile));
        return document;
    }

 public void write(Document document) throws IOException {

        // xml的格式，System.out显示(

        OutputFormat format = OutputFormat.createPrettyPrint();
        XMLWriter writer = new XMLWriter( System.out, format );
        System.out.println("\r\n------------------Start------------------");
        writer.write( document );
         System.out.println("\r\n-------------------End-------------------");
   }

 public static void main(String[] args) {
  Parse_1 dom4j = new Parse_1();
  try {
   dom4j.write(dom4j.parse("c:\\output.xml"));

  } catch (IOException e) {
   System.out.println(e.getMessage());
  } catch (DocumentException e) {
   System.out.println(e.getMessage());
  }
 }
}

运行过程和结果：

C:\test>dom4j

C:\test>set CLASSPATH=c:\test\jar\jaxen-1.1-beta-10.jar;c:\test\jar\dom4j-1.6.1.
jar;.;c:\jdk1.5\lib

C:\test>javac Parse_1.java

C:\test>java Parse_1

------------------Start------------------
<?xml version="1.0" encoding="UTF-8"?>

<root>
<author name="James" location="UK">James Strachan</author>
<author name="Bob" location="US">Bob McWhirter</author>
</root>

-------------------End-------------------

C:\test>

三、获取、修改XML元素

代码如下：

import java.io.IOException;
import java.io.File;
import java.util.Iterator;
import java.util.List;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.XMLWriter;
import org.dom4j.io.SAXReader;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Node;
import org.dom4j.Element;
import org.dom4j.io.OutputFormat;
import org.dom4j.Attribute;
 
public class Parse_2 {

 public Document parse(String sfile) throws DocumentException {
        SAXReader reader = new SAXReader();
        Document document = reader.read(new File(sfile));
        return document;
    }
 
 public void bar(Document document) throws IOException {


    List list = document.selectNodes( "//author" );
    Iterator iter=list.iterator();
  
  System.out.println("\r\n****** 获取的数据如下 ******");
  while(iter.hasNext()){
   Element titleElement=(Element)iter.next();
   // 修改xml元素

   if(titleElement.getText().equals("James Strachan")) {
    titleElement.setText("Faint Heipark");
   }
   System.out.print(titleElement.valueOf( "@name" ) + "：");
   System.out.println(titleElement.getText());
  }
  
  // 输出全部原始数据

  OutputFormat format = OutputFormat.createPrettyPrint();
        XMLWriter writer = new XMLWriter( System.out, format );
  System.out.println("\r\n------------------Start------------------");
        writer.write( document );
  System.out.println("\r\n-------------------End-------------------");
    }

 public static void main(String[] args) {
  Parse_2 dom4j = new Parse_2();
  try {
   dom4j.bar(dom4j.parse("c:\\output.xml"));

  } catch (Exception e) {
   System.out.println(e.getMessage());
  }
 }
}

运行结果：

C:\test>java Parse_2

****** 获取的数据如下 ******
James：Faint Heipark
Bob：Bob McWhirter

------------------Start------------------
<?xml version="1.0" encoding="UTF-8"?>

<root>
<author name="James" location="UK">Faint Heipark</author>
<author name="Bob" location="US">Bob McWhirter</author>
</root>

-------------------End-------------------