XML 处理利器 : XStream

时间：2021-07-10 12:22:36

XStream 概述

     XStream 是一套简洁易用的开发类库，用于将Java对象序列化为XML或者将XML反序列化为JAVA对象，是JAVA对象和XML之间一个双向转换器。

举例

    采用User用户对象和LoginLog登录日志对象作为XStream实例转换对象. 例子简单，直接贴代码了.
       User.java 
        
package com.baobaotao.domain;

import java.io.Serializable;

import java.util.ArrayList;

import java.util.Date;

import java.util.List;

import java.util.Map;

public class User implements Serializable {

	private int userId;

	private String userName;

	private String password;

	private int credits;

	private String lastIp;

	private Date lastVisit;

	private List logs;

	private Map datas;

	public List<LoginLog> getLogs() {

		return logs;

	}

	public void setLogs(List logs) {

		this.logs = logs;

	}

	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 getPassword() {

		return password;

	}

	public void setPassword(String password) {

		this.password = password;

	}

	public int getCredits() {

		return credits;

	}

	public void setCredits(int credits) {

		this.credits = credits;

	}

	public String getLastIp() {

		return lastIp;

	}

	public void setLastIp(String lastIp) {

		this.lastIp = lastIp;

	}

	public Date getLastVisit() {

		return lastVisit;

	}

	public void setLastVisit(Date lastVisit) {

		this.lastVisit = lastVisit;

	}

	public void addLoginLog(LoginLog log){

		if(this.logs==null){

			logs = new ArrayList<LoginLog>();

		}

		logs.add(log);

	}

	public Map getDatas() {

		return datas;

	}

	public void setDatas(Map datas) {

		this.datas = datas;

	}

}

LoginLog.java

package com.baobaotao.domain;

import java.io.Serializable;

import java.util.Date;

public class LoginLog implements Serializable {

	private int loginLogId;

	private int userId;

	private String ip;

	private Date loginDate;

	public int getLoginLogId() {

		return loginLogId;

	}

	public void setLoginLogId(int loginLogId) {

		this.loginLogId = loginLogId;

	}

	public int getUserId() {

		return userId;

	}

	public void setUserId(int userId) {

		this.userId = userId;

	}

	public String getIp() {

		return ip;

	}

	public void setIp(String ip) {

		this.ip = ip;

	}

	public Date getLoginDate() {

		return loginDate;

	}

	public void setLoginDate(Date loginDate) {

		this.loginDate = loginDate;

	}

}

下面就开始使用XStream进行对象与 XML之间的转换.

package com.baobaotao.oxm.xtream;

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.util.Date;

import com.baobaotao.domain.LoginLog;

import com.baobaotao.domain.User;

import com.thoughtworks.xstream.XStream;

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

public class XStreamSample {

    private static XStream xstream;

    static{

    	//创建XStream实例并指定一个XML	解析器

    	xstream=new XStream(new DomDriver());

    }

    //初始化转换对象

    public static User getUser(){

    	LoginLog log1=new LoginLog();

    	log1.setIp("192.168.1.91");

    	log1.setLoginDate(new Date());

    	User user=new User();

    	user.setUserId(1);

    	user.setUserName("xstream");

    	user.addLoginLog(log1);

    	return user;

    }

    //Java  对象转换成XML

    public static void objectToXML() throws Exception{

    	//获取转换User对象的实例

    	User user=getUser();

    	//实例化一个文件输出流

    	FileOutputStream fileOutputStream=new FileOutputStream("XStreamSample.xml");

    	//将User对象转换为XML,并保存到指定文件

    	xstream.toXML(user,fileOutputStream);

    }

    //XML转换为Java对象

    public static User XMLToObject() throws Exception{

    	//实例化一个文件输入流

    	FileInputStream inputStream=new FileInputStream("XStreamSample.xml");

    	//将XML文件输入流转化为对象

    	User user=(User) xstream.fromXML(inputStream);

    	for(LoginLog log :user.getLogs()){

    		if(log!=null){

    			System.out.println("访问IP:"+log.getIp());

    		}

    	}

    }

}

编写测试类

package com.baobaotao.oxm.xstream;

import static org.junit.Assert.assertEquals;

import static org.junit.Assert.assertNotNull;

import java.io.BufferedReader;

import java.io.FileReader;

import org.junit.Test;

import com.baobaotao.domain.LoginLog;

import com.baobaotao.domain.User;

import com.baobaotao.oxm.xtream.XStreamSample;

public class TestXStreamSample {

	@Test

	public void objectToXml()throws Exception {

		XStreamSample.objectToXML();

		FileReader reader = new FileReader("XStreamSample.xml");

		BufferedReader br = new BufferedReader(reader);

		StringBuffer sb = new StringBuffer("");

		String s;

		while ((s = br.readLine()) != null) {

			sb.append(s);

		}

		System.out.println(sb.toString());

		reader.close();

		br.close();

//		assertXpathExists("//com.baobaotao.domain.User",sb.toString());

//		assertXpathExists("//credits",sb.toString());

//		assertXpathExists("//userName",sb.toString());

//		assertXpathExists("//com.baobaotao.domain.LoginLog",sb.toString());

	}

	@Test

	public void xmlToObject()throws Exception  {

		XStreamSample.objectToXML();

		User u = XStreamSample.XMLToObject();

		assertNotNull(u);

		assertEquals("xstream", u.getUserName());

		for (LoginLog log : u.getLogs()) {

			assertNotNull(log);

			assertNotNull(log.getIp());

			assertNotNull(log.getLoginDate());

		}

	}

}

生成的XML文件如下：

<com.baobaotao.domain.User>

  <userId>1</userId>

  <userName>xstream</userName>

  <credits>0</credits>

  <logs>

    <com.baobaotao.domain.LoginLog>

      <loginLogId>0</loginLogId>

      <userId>0</userId>

      <ip>192.168.1.91</ip>

      <loginDate>2015-03-25 07:44:05.783 UTC</loginDate>

    </com.baobaotao.domain.LoginLog>

  </logs>

</com.baobaotao.domain.User>

使用XStream 别名

        在默认情况下，Java对象映射到XML的映射，是Java对象属性名对应XML的元素名，Java类的全名对应XML根元素的名字。在实际的应用中，如果XML和Java类都已经存在相应的名字，在进行转换时，需要设置别名进行映射。
        XStream别名配置包含三种情况:
        类别名，用alias(String name ,Class type);
        类成员别名，用aliasField(String alias,Class definedIn,String fieldName);yo
        类成员作为属性别名，用aliasAttribute(Class definedIn,String attributeName,String alias)  ,单独命名没有意义，还要通过useAttributeFor(Class definedIn,String fieldName) 应用到某个类上。


package com.baobaotao.oxm.xtream.alias;

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.util.Date;

import com.baobaotao.domain.LoginLog;

import com.baobaotao.domain.User;

import com.thoughtworks.xstream.XStream;

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

/**

 * 别名

 * @author yulei

 */

public class XStreamAliasSample {

    private static XStream xstream;

      static {

    		xstream=new XStream(new DomDriver());

    		//设置类别名，默认为当前类名称加上包名

    		xstream.alias("loginLog", LoginLog.class);

    		xstream.alias("user", User.class);

    		//设置类成员别名

    		xstream.aliasField("id", User.class, "userId");

    		//把LoginLog的userId属性视为XML属性，默认为XML的元素

    		xstream.aliasAttribute(LoginLog.class, "userId","id");

    		xstream.useAttributeFor(LoginLog.class, "userId");

    		//去掉集合类型生成XML的父节点，即忽略XML中的<logs></logs>标记

    		xstream.addImplicitCollection(User.class,"logs");

      }

    //初始化转换对象

      public static User getUser(){

      	LoginLog log1=new LoginLog();

      	log1.setIp("192.168.1.91");

      	log1.setLoginDate(new Date());

      	User user=new User();

      	user.setUserId(1);

      	user.setUserName("xstream");

      	user.addLoginLog(log1);

      	return user;

      }

      //Java  对象转换成XML

      public static void objectToXML() throws Exception{

      	//获取转换User对象的实例

      	User user=getUser();

      	//实例化一个文件输出流

      	FileOutputStream fileOutputStream=new FileOutputStream("XStreamSample.xml");

      	//将User对象转换为XML,并保存到指定文件

      	xstream.toXML(user,fileOutputStream);

      }

      //XML转换为Java对象

      public static User XMLToObject() throws Exception{

      	//实例化一个文件输入流

      	FileInputStream inputStream=new FileInputStream("XStreamSample.xml");

      	//将XML文件输入流转化为对象

      	User user=(User) xstream.fromXML(inputStream);

      	for(LoginLog log :user.getLogs()){

      		if(log!=null){

      			System.out.println("访问IP:"+log.getIp());

      		}

      	}

  		return user;

      }

}





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