XML 处理利器 : XStream

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 {@Testpublic 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());}@Testpublic 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;      }}