XStream 可以方便地把java对象序列化为XML,和把XML反序列化为java对象。

引入XStream的包：

 <!-- XStream -->
         <dependency>
            <groupId>com.thoughtworks.xstream</groupId>
            <artifactId>xstream</artifactId>
            <version>1.4.9</version>
        </dependency>

实体类：

package cn.framework.t1;

import java.util.ArrayList;
import java.util.Date;
import java.util.List;

public class User {
	private int userId;
	private String userName;
	private String pwd;
	private List<UserLog> logs=new ArrayList<UserLog>();
	private Date lastVisted;
	public int getUserId() {
		return userId;
	}
	public void setUserId(int userId) {
		this.userId = userId;
	}
	public String getUserName() {
		return userName;
	}
	public void setUserName(String userName) {
		this.userName = userName;
	}
	public String getPwd() {
		return pwd;
	}
	public void setPwd(String pwd) {
		this.pwd = pwd;
	}
	public List getLogs() {
		return logs;
	}
	public void setLogs(List logs) {
		this.logs = logs;
	}
	public Date getLastVisted() {
		return lastVisted;
	}
	public void setLastVisted(Date lastVisted) {
		this.lastVisted = lastVisted;
	}
	@Override
	public String toString() {
		return "User [userId=" + userId + ",userName=" + userName + ",pwd="
				+ pwd + ",logs=" + logs + ",lastVisted=" + lastVisted + "]";
	}
	
	
}

package cn.framework.t1;

public class UserLog {
	private int logId;
	private String ip;
	
	public int getLogId() {
		return logId;
	}
	public void setLogId(int logId) {
		this.logId = logId;
	}
	public String getIp() {
		return ip;
	}
	public void setIp(String ip) {
		this.ip = ip;
	}
	@Override
	public String toString() {
		return "UserLog [logId=" + logId + ",ip=" + ip + "]";
	}
	
	
}

package cn.framework.t1;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;

import org.apache.log4j.Logger;

import com.thoughtworks.xstream.XStream;
import com.thoughtworks.xstream.io.xml.DomDriver;

public class XStreamUtils {
	private static final Logger logger=Logger.getLogger("cn.framework.t1.XStreamUtils");
	
	private static XStream xstream;
	static{
		logger.info("init xstream ...");
		xstream=new XStream(new DomDriver());
		
		/*******对生成的xml做一些设置*******/
		//设置别名，不设置将采用完全类名
		xstream.alias("User",User.class);
		xstream.alias("UserLog",UserLog.class);
		
		//设置类成员别名
		xstream.aliasField("id",User.class,"userId");
		
		//类的属性默认为xml的元素，现在修改为xml属性
		xstream.aliasAttribute(UserLog.class,"logId","lid");
		xstream.useAttributeFor(UserLog.class,"logId");
		
		//只保留集合内元素，去掉上级标签
		xstream.addImplicitCollection(User.class,"logs");
	}
	
	public static void objectToXML(User user) throws FileNotFoundException{
		logger.info("do objectToXML ...");
		FileOutputStream fileOutputStream = new FileOutputStream("e:/out/xstream_user.xml");
		xstream.toXML(user,fileOutputStream);
	}
	
	public static void xmlToObject() throws FileNotFoundException{
		logger.info("do xmlToObject ...");
		FileInputStream input = new FileInputStream("e:/out/xstream_user.xml");
		User user=(User) xstream.fromXML(input);
		System.out.println(user);
	}
	
	
}

package cn.framework.t1;

import java.io.FileNotFoundException;
import java.util.Date;

public class Test {

	public static void main(String[] args) throws FileNotFoundException {
		User user = new User();
		user.setLastVisted(new Date());
		user.setPwd("123456");
		user.setUserId(1);
		user.setUserName("aaa");
		
		
		UserLog userLog = new UserLog();
		userLog.setIp("127.0.0.1");
		userLog.setLogId(1);
		user.getLogs().add(userLog);
		
		UserLog userLog1 = new UserLog();
		userLog1.setIp("127.0.0.1");
		userLog1.setLogId(2);
		user.getLogs().add(userLog1);
		
		XStreamUtils.objectToXML(user);
		
//		XStreamUtils.xmlToObject();

	}

}

默认生成的xml格式：

<cn.framework.t1.User>
  <userId>1</userId>
  <userName>aaa</userName>
  <pwd>123456</pwd>
  <logs>
    <cn.framework.t1.UserLog>
      <logId>1</logId>
      <ip>127.0.0.1</ip>
    </cn.framework.t1.UserLog>
    <cn.framework.t1.UserLog>
      <logId>2</logId>
      <ip>127.0.0.1</ip>
    </cn.framework.t1.UserLog>
  </logs>
  <lastVisted>2017-12-06 03:23:50.11 UTC</lastVisted>
</cn.framework.t1.User>

<User>
  <id>1</id>
  <userName>aaa</userName>
  <pwd>123456</pwd>
  <UserLog lid="1">
    <ip>127.0.0.1</ip>
  </UserLog>
  <UserLog lid="2">
    <ip>127.0.0.1</ip>
  </UserLog>
  <lastVisted>2017-12-06 03:25:00.193 UTC</lastVisted>
</User>