dom4j是一个优秀的开源项目,专用于xml文件的读写,而且支持强大的xpath.
下面的代码演示了对xml文件demo.xml的读写
demo.xml内容:
1 <?xml version="1.0" encoding="UTF-8" ?>
2 <address-list>
3 <card name="yangjm" id="1">
4 <sex>男</sex>
5 <address><![CDATA[中国上海外滩No.01]]> </address>
6 <telephone>13916732212</telephone>
7 </card>
8 <card name="zhangsan" id="2">
9 <sex>女</sex>
10 <address>
11 <item type="家庭地址"><![CDATA[中国.北京.东直门外大街]]> </item>
12 <item type="单位地址"><![CDATA[中国.上海.田林路888号]]> </item>
13 </address>
14 <telephone>010-123123</telephone>
15 </card>
16 </address-list>
java代码:
1 package jmyang.dom4j;
2
3 /**
4 * <p>Title:dom4j测试 </p>
5 * <p>Description: 使用xpath读取节点内容、属性</p>
6 * <p>Copyright: Copyright (c) 2012</p>
7 * <p>Company: infosky.com.cn</p>
8 * @author:yjmyzz@126.com 菩提树下的杨过
9 * @version 1.0
10 */
11
12 import java.util.*;
13 import java.io.*;
14 import org.dom4j.*;
15 import org.dom4j.io.*;
16
17
18 public class XmlTest {
19
20
21 public static void Test() {
22 String fileName = System.getProperty("user.dir") + "\\demo.xml"; //当前路径下的demo.xml
23
24 try {
25 SAXReader reader = new SAXReader();
26 Document doc = reader.read(fileName); //加载xml文件
27
28 List peoples = doc.selectNodes("//*[@name]"); //选择所有具有name属性的节点(即demo.xml中的所有card节点)
29 for (Iterator iter = peoples.iterator(); iter.hasNext(); ) {
30 Element card = (Element) iter.next();
31 //System.out.println(node.asXML());
32 //System.out.println("---------------------------------------");
33 //System.out.println(node.attributeCount());
34 List attrList = card.attributes();
35 //输出每个card的所有属性
36 for (Iterator attr = attrList.iterator(); attr.hasNext(); ) {
37 Attribute a = (Attribute) attr.next();
38 System.out.println(a.getName() + "=" + a.getValue());
39
40 }
41 System.out.println(
42 "----------------------------------------------------");
43 }
44
45 Element zhangsan = (Element) doc.selectSingleNode("//card[@id='2']"); //查找“id属性”=2的card元素
46 System.out.println("张三的名称:" + zhangsan.attribute("name").getValue()); //输出zhangsan的name属性
47
48 Node addrFamily = zhangsan.selectSingleNode("./address/item[2]"); //选择zhangsan元素下的address节点下的第2个item子节点
49 System.out.println("张三的单位地址:" + addrFamily.getStringValue()); //输出cdata内容
50
51 System.out.println(
52 "----------------------------------------------------");
53 //为zhangsan下增加二个节点
54 zhangsan.addElement("email").addAttribute("type",
55 "工作").addText("work@some-domain.com");
56 zhangsan.addElement("email").addAttribute("type",
57 "私人").addCDATA("private@some-domain.com"); //设置CDATA内容
58
59 System.out.println(zhangsan.asXML()); //打印zhangsan节点的xml内容(调试用)
60 System.out.println(
61 "----------------------------------------------------");
62
63 //将上述改动保存到文件demo2.xml
64 FileWriter fileWriter = new FileWriter(System.getProperty(
65 "user.dir") + "\\demo2.xml");
66
67 OutputFormat format = OutputFormat.createPrettyPrint(); //设置美观的缩进格式,便于阅读
68 //format = OutputFormat.createCompactFormat();//设置紧凑格式(消除多余空格),便于下载
69 XMLWriter writer = new XMLWriter(System.out, format);
70 writer.setWriter(fileWriter);
71 writer.write(doc);
72 writer.close();
73
74 } catch (Exception e) {
75 e.printStackTrace();
76 }
77
78 }
79 }
运行结果:
name=yangjm id=1 ---------------------------------------------------- name=zhangsan id=2 ---------------------------------------------------- 张三的名称:zhangsan 张三的单位地址:中国.上海.田林路888号 ---------------------------------------------------- <card name="zhangsan" id="2"> <sex>女</sex> <address> <item type="家庭地址"><![CDATA[中国.北京.东直门外大街]]> </item> <item type="单位地址"><![CDATA[中国.上海.田林路888号]]> </item> </address> <telephone>010-123123</telephone> <email type="工作">work@some-domain.com</email><email type="私人"><![CDATA[private@some-domain.com]]></email></card> ----------------------------------------------------
保存后的demo2.xml
<?xml version="1.0" encoding="UTF-8"?>
<address-list> <card name="yangjm" id="1"> <sex>男</sex> <address><![CDATA[中国上海外滩No.01]]> </address> <telephone>13916732212</telephone> </card> <card name="zhangsan" id="2"> <sex>女</sex> <address> <item type="家庭地址"><![CDATA[中国.北京.东直门外大街]]> </item> <item type="单位地址"><![CDATA[中国.上海.田林路888号]]> </item> </address> <telephone>010-123123</telephone> <email type="工作">work@some-domain.com</email> <email type="私人"><![CDATA[private@some-domain.com]]></email> </card> </address-list>
最后注意一点:dom4j支持xpath语法,但该特性需要jaxen包的支持(编译期不需要,仅运行时需要),所以需要在项目中引入该包,如果是maven项目,要加入
<dependency>
<groupId>jaxen</groupId>
<artifactId>jaxen</artifactId>
<version>1.1.3-redhat-2</version>
</dependency>
否则运行时会提示"类找不到"之类的错误