XML 和 java对象相互转换

xml和Java对象的转换不需要任何的第三方包，JDK自带这个转换API，方便简洁。

下面使用的是JDK自带的类，没有引用任何第三方jar包。

 

Unmarshaller 类使客户端应用程序能够将 XML 数据转换为 Java 内容对象树。

备注：marshal(序列化、排列、整理)

Marshaller 类使客户端应用程序能够将 Java 内容树转换回 XML 数据。

实体类(这个是要被包含的实体类，不需要加注解)一:

package org.ywzn.po;public class User {private String id;private String name;private String passwrod;public User() {super();}public User(String id, String name, String passwrod) {super();this.id = id;this.name = name;this.passwrod = passwrod;}public String getId() {return id;}public void setId(String id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public String getPasswrod() {return passwrod;}public void setPasswrod(String passwrod) {this.passwrod = passwrod;}@Overridepublic String toString() {return "User [id=" + id + ", name=" + name + ", passwrod=" + passwrod+ "]";}}

实体类二:

package org.ywzn.po;import javax.xml.bind.annotation.XmlRootElement;@XmlRootElementpublic class Room {private String id;private String address;private User user;public Room() {super();}public Room(String id, String address, User user) {super();this.id = id;this.address = address;this.user = user;}public String getId() {return id;}public void setId(String id) {this.id = id;}public String getAddress() {return address;}public void setAddress(String address) {this.address = address;}public User getUser() {return user;}public void setUser(User user) {this.user = user;}@Overridepublic String toString() {return "Room [id=" + id + ", address=" + address + ", user=" + user+ "]";}}

注意：

1、需要转换的model对象一定要添加@XmlRootElement注解，其里面的其他对象则不需要

2、需要转换的model对象一定要有不带参数的构造方法，包括该对象里面引用的对象。

测试Java对象转xml:

package org.ywzn.main;import javax.xml.bind.JAXBContext;import javax.xml.bind.JAXBException;import javax.xml.bind.Marshaller;import org.ywzn.po.Room;import org.ywzn.po.User;public class App {public static void main(String[] args) {// TODO Auto-generated method stubUser user = new User("1","夏小雪","111");Room room = new Room("1","桂林",user);try {JAXBContext context = JAXBContext.newInstance(Room.class);Marshaller createMarshaller = context.createMarshaller();createMarshaller.marshal(room,System.out);} catch (JAXBException e) {e.printStackTrace();}}}

输出:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?><room><address>桂林</address><id>1</id><user><id>1</id><name>夏小雪</name><passwrod>111</passwrod></user></room>

测试xml转Java对象:

package org.ywzn.main;import java.io.StringReader;import javax.xml.bind.JAXBContext;import javax.xml.bind.JAXBException;import javax.xml.bind.Unmarshaller;import org.ywzn.po.Room;public class App2 {public static void main(String[] args) {// TODO Auto-generated method stubString xmlStr = "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?><room><address>厦门</address><id>1</id><user><id>1</id><name>易中天</name><passwrod>111</passwrod></user></room>";          try {              JAXBContext context = JAXBContext.newInstance(Room.class);              Unmarshaller unmarshaller = context.createUnmarshaller();              Room room = (Room)unmarshaller.unmarshal(new StringReader(xmlStr));              System.out.println(room);        } catch (JAXBException e) {              e.printStackTrace();          }  }}

输出:

Room [id=1, address=厦门, user=User [id=1, name=易中天, passwrod=111]]

测试编码与是否省略xml头:

package org.ywzn.main;import javax.xml.bind.JAXBContext;import javax.xml.bind.JAXBException;import javax.xml.bind.Marshaller;import org.ywzn.po.Room;import org.ywzn.po.User;public class Java2XMLSetEncode {public static void main(String[] args) {// TODO Auto-generated method stubUser user = new User("1", "夏小雪", "111");Room room = new Room("1", "桂林", user);try {JAXBContext context = JAXBContext.newInstance(Room.class);Marshaller createMarshaller = context.createMarshaller();createMarshaller.setProperty(Marshaller.JAXB_ENCODING, "UTF-8");// 编码格式createMarshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);// 是否格式化生成的xml串createMarshaller.setProperty(Marshaller.JAXB_FRAGMENT, false);// 是否省略xml头信息（<?xmlcreateMarshaller.marshal(room, System.out);} catch (JAXBException e) {e.printStackTrace();}}}

输出结果:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?><room>    <address>桂林</address>    <id>1</id>    <user>        <id>1</id>        <name>夏小雪</name>        <passwrod>111</passwrod>    </user></room>

JAXB（Java Architecture for XML Binding) 是一个业界的标准，是一项可以根据XML Schema产生Java类的技术。该过程中，JAXB也提供了将XML实例文档反向生成Java对象树的方法，并能将Java对象树的内容重新写到XML实例文档。从另一方面来讲，JAXB提供了快速而简便的方法将XML模式绑定到Java表示，从而使得Java开发者在Java应用程序中能方便地结合XML数据和处理函数。

 

    JAXBContext 类提供到 JAXB API 的客户端入口点。它提供了管理实现 JAXB 绑定框架操作所需的 XML/Java 绑定信息的抽象，这些操作包括：解组、编组和验证。

Demo的下载地址->这里

http://download.csdn.net/detail/u014175572/8721559