xStream完美转换XML、JSON

前端之家收集整理的这篇文章主要介绍了xStream完美转换XML、JSON前端之家小编觉得挺不错的,现在分享给大家,也给大家做个参考。

原文地址:http://blog.csdn.net/ibm_hoojo/article/details/6342386

xStream框架

xStream可以轻易的将Java对象和xml文档相互转换,而且可以修改某个特定的属性和节点名称,而且也支持json的转换;

前面有介绍过json-lib这个框架,在线博文:http://www.cnblogs.com/hoojo/archive/2011/04/21/2023805.html

以及Jackson这个框架,在线博文:http://www.cnblogs.com/hoojo/archive/2011/04/22/2024628.html

它们都完美支持JSON,但是对xml的支持还不是很好。一定程度上限制了对Java对象的描述,不能让xml完全体现到对Java对象的描述。这里将会介绍xStream对JSON、XML的完美支持。xStream不仅对XML的转换非常友好,而且提供annotation注解,可以在JavaBean中完成对xml节点、属性的描述。以及对JSON也支持,只需要提供相关的JSONDriver就可以完成转换。

一、准备工作

1、 下载jar包、及官方资源

xStream的jar下载地址:

https://nexus.codehaus.org/content/repositories/releases/com/thoughtworks/xstream/xstream-distribution/1.3.1/xstream-distribution-1.3.1-bin.zip

官方的示例很全,官方参考示例:http://xstream.codehaus.org/tutorial.html

添加xstream-1.3.1.jar文件到工程中,就可以开始下面的工作;需要的jar如下:

2、测试用例代码

package com.hoo.test;
 
  
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.StringReader;
import java.io.Writer;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.codehaus.jettison.json.JSONException;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import com.hoo.entity.Birthday;
import com.hoo.entity.Classes;
import com.hoo.entity.ListBean;
import com.hoo.entity.Student;
import com.thoughtworks.xstream.XStream;
import com.thoughtworks.xstream.io.HierarchicalStreamWriter;
import com.thoughtworks.xstream.io.json.JettisonMappedXmlDriver;
import com.thoughtworks.xstream.io.json.JsonHierarchicalStreamDriver;
import com.thoughtworks.xstream.io.json.JsonWriter;
 
  
/**
 * <b>function:</b>Java对象和XML字符串的相互转换
 * jar-lib-version: xstream-1.3.1
 * @author hoojo
 * @createDate Nov 27,2010 12:15:15 PM
 * @file XStreamTest.java
 * @package com.hoo.test
 * @project WebHttpUtils
 * @blog http://blog.csdn.net/IBM_hoojo
 * @email hoojo_@126.com
 * @version 1.0
 */
@SuppressWarnings("unchecked")
public class XStreamTest {
    
    private XStream xstream = null;
private ObjectOutputStream  out = null;
private ObjectInputStream in = null;
private Student bean = null;
/**
     * <b>function:</b>初始化资源准备
     * @author hoojo
     * @createDate Nov 27,2010 12:16:28 PM
     */
    @Before
void init() {
        try {
            xstream = new XStream();
            //xstream = new XStream(new DomDriver()); // 需要xpp3 jar
        } catch (Exception e) {
            e.printStackTrace();
        }
        bean = new Student();
        bean.setAddress("china");
        bean.setEmail("jack@email.com");
        bean.setId(1);
        bean.setName("jack");
        Birthday day = new Birthday();
        day.setBirthday("2010-11-22");
        bean.setBirthday(day);
    }
    
     * <b>function:</b>释放对象资源
     * @author hoojo
     */
    @After
void destory() {
        xstream = null;
        bean = null;
try {
if (out != null) {
                out.flush();
                out.close();
            }
if (in != null) {
                in.close();
            }
catch (IOException e) {
        System.gc();
    }
final void fail(String string) {
        System.out.println(string);
void failRed(String string) {
        System.err.println(string);
}

通过XStream对象的toXML方法就可以完成Java对象到XML的转换,toXML方法还有2个相同签名的方法,需要传递一个流。然后通过流来完成xml信息的输出

3、 需要的JavaBean

package com.hoo.entity;
class Student {
private int id;
private String name;
private String email;
private String address;
private Birthday birthday;
//getter、setter
public String toString() {
return this.name + "#" + this.id + this.address + this.birthday + this.email;
}

二、Java转换成XML

1、 JavaBean转换XM

* <b>function:</b>Java对象转换成XML字符串
@Test
void writeBean2XML() {
        fail("------------Bean->XML------------");
        fail(xstream.toXML(bean));
"重命名后的XML");
//类重命名
//xstream.alias("account",Student.class);
//xstream.alias("生日",Birthday.class);
//xstream.aliasField("生日",Student.class,"birthday");
 
  
//fail(xstream.toXML(bean));
//属性重命名
        xstream.aliasField("邮件",Student.class,"email");
//包重命名
        xstream.aliasPackage("hoo",128)">"com.hoo.entity");
    }         e.printStackTrace();
}

看结果中的第一份xml内容,是没有经过然后修改重命名的文档,按照原样输出。文档中的第二份文档的package经过重命名,email属性也经过重命名以及类名也可以进行重命名的。

运行后结果如下:

------------Bean->XML------------
<com.hoo.entity.Student>
  <id>1</id>
<name>jack</name<email>jack@email.com</email<address>china</<birthday>2010-11-22</birthday</com重命名后的XML
<hoo<邮件</邮件</hoo>

2、 将List集合转换成xml文档

* <b>function:</b>将Java的List集合转换成XML对象
void writeList2XML() {
//修改元素名称
        xstream.alias("beans",ListBean.class);
"student",255)">class);
"----------List-->XML----------");
        ListBean listBean = new ListBean();
        listBean.setName("this is a List Collection");
        
        List<Object> list = new ArrayList<Object>();
        list.add(bean);
        list.add(bean);//引用bean
//list.add(listBean);//引用listBean,父元素
        
new Student();
"china");
"tom@125.com");
        bean.setId(2);
"tom");
new Birthday(        listBean.setList(list);
//将ListBean中的集合设置空元素,即不显示集合元素标签
//xstream.addImplicitCollection(ListBean.class,"list");
//设置reference模型
//xstream.setMode(XStream.NO_REFERENCES);//不引用
        xstream.setMode(XStream.ID_REFERENCES);//id引用
//xstream.setMode(XStream.XPATH_ABSOLUTE_REFERENCES);//绝对路径引用
          
//将name设置为父类(Student)的元素的属性
        xstream.useAttributeFor(Student."name");
        xstream.useAttributeFor(Birthday."birthday");
//修改属性的name
        xstream.aliasAttribute("姓名",128)">"name");
"生日",Birthday."birthday");
      
        fail(xstream.toXML(listBean));
catch (Exception e) {
        e.printStackTrace();
}

上面的代码运行后,结果如下:

----------List-->XML----------
<beans id="1">this is a List Collection<list id="2"<student id="3" 姓名="jack"      <birthday id="4" 生日="2010-11-22"/</student<student reference="3"/<student id="5" 姓名="tom">2>tom@125<birthday id="6" 生日="2010-11-22"/</list</beans>

如果不加xstream.addImplicitCollection(ListBean.class,"list");

这个设置的话,会出现一个List节点包裹着Student节点元素。添加addImplicitCollection可以忽略这个list节点元素。那么上面的list节点就不存在,只会在beans元素中出现name、student这2个xml元素标签

setMode是设置相同的对象的引用方式,如果设置XStream.NO_REFERENCES就是不引用,会输出2分相同的Student元素。如果是XStream.ID_REFERENCES会引用相同的那个对象的id属性,如果是XStream.XPATH_ABSOLUTE_REFERENCES引用,那么它将显示xpath路径。上面采用的id引用,<student reference="3"/>这个引用了id=3的那个student标签元素;

useAttributeFor是设置某个节点显示到父节点的属性中,也就是将指定class中的指定属性,在这个class元素节点的属性显示

如:<student><name>hoojo</name></student>

设置好后就是这样的结果:<student name=”hoojo”></student>

aliasAttribute是修改属性名称

3、 在JavaBean中添加Annotation注解进行重命名设置

先看看JavaBean的代码

import java.util.Arrays;
import java.util.Calendar;
import java.util.GregorianCalendar;
import java.util.List;
import com.thoughtworks.xstream.annotations.XStreamAlias;
import com.thoughtworks.xstream.annotations.XStreamAsAttribute;
import com.thoughtworks.xstream.annotations.XStreamConverter;
import com.thoughtworks.xstream.annotations.XStreamImplicit;
import com.thoughtworks.xstream.annotations.XStreamOmitField;
@XStreamAlias("class")
class Classes {
/*
     * 设置属性显示
    @XStreamAsAttribute
    @XStreamAlias("名称")
/*
     * 忽略
    @XStreamOmitField
int number;
    @XStreamImplicit(itemFieldName = "Students")
private List<Student> students;
    @SuppressWarnings("unused")
    @XStreamConverter(SingleValueCalendarConverter.class)
private Calendar created = new GregorianCalendar();
public Classes(){}
public Classes(String name,Student... stu) {
this.name = name;
this.students = Arrays.asList(stu);
//getter、setter
}

SingleValueCalendarConverter.java这个是一个类型转换器

import java.util.Calendar;
import java.util.Date;
import com.thoughtworks.xstream.converters.Converter;
import com.thoughtworks.xstream.converters.MarshallingContext;
import com.thoughtworks.xstream.converters.UnmarshallingContext;
import com.thoughtworks.xstream.io.HierarchicalStreamReader;
import com.thoughtworks.xstream.io.HierarchicalStreamWriter;
class SingleValueCalendarConverter implements Converter {
     void marshal(Object source,HierarchicalStreamWriter writer,
                MarshallingContext context) {
            Calendar calendar = (Calendar) source;
            writer.setValue(String.valueOf(calendar.getTime().getTime()));
public Object unmarshal(HierarchicalStreamReader reader,monospace; direction:ltr; font-size:10pt; overflow:visible">                UnmarshallingContext context) {
            GregorianCalendar calendar = new GregorianCalendar();
            calendar.setTime(new Date(Long.parseLong(reader.getValue())));
return calendar;
        }
        @SuppressWarnings(boolean canConvert(Class type) {
return type.equals(GregorianCalendar.}

再看看测试用例代码

@Test
void writeList2XML4Annotation() {
        failRed("---------annotation Bean --> XML---------");
        Student stu =         stu.setName(        Classes c = new Classes("一班",bean,stu);
        c.setNumber(2);
//对指定的类使用Annotation
//xstream.processAnnotations(Classes.class);
//启用Annotation
//xstream.autodetectAnnotations(true);
        fail(xstream.toXML(c));
}

当启用annotation或是对某个特定的类启用annotation时,上面的classes这个类才有效果。如果不启用annotation,运行后结果如下:

---------annotation Bean --> XML---------
.Classes>一班<number</number<students class="java.util.Arrays$ArrayList"<a class="student-array"<student          >0</a</students<created<time>1303292056718</time<timezone>Asia/Shanghai</timezone</created>

当启用annotation后xstream.processAnnotations(Classes.class),结果如下:

<class 名称="一班"<Students</Students>1303292242937</class>

4、 Map集合转换xml文档

* <b>function:</b>Java Map集合转XML
void writeMap2XML() {
"---------Map --> XML---------");
        Map<String,Student> map = new HashMap<String,Student>();
        map.put("No.1",bean);//put
"No.2",0)">//put
"jack");
"No.3",128)">"key",String."id");
        xstream.useAttributeFor("birthday",monospace; direction:ltr; font-size:10pt; overflow:visible">        fail(xstream.toXML(map));
}

运行后结果如下:

---------Map --map<entry<key>No.3</key<student id="0"</entry>No.1<student id="1"<birthday birthday="2010-11-22"/>No.2<student id="2">tom>

5、 用OutStream输出流写XML

* <b>function:</b>用OutStream输出流写XML
void writeXML4OutStream() {
        out = xstream.createObjectOutputStream(System.out);
        c.setNumber(2);
"---------ObjectOutputStream # JavaObject--> XML---------");
        out.writeObject(stu);
        out.writeObject("2010-05-33"));
        out.write(22);//byte
        out.writeBoolean(true);
        out.writeFloat(22.f);
        out.writeUTF("hello");
}

使用输出流后,可以通过流对象完成xml的构建,即使没有JavaBean对象,你可以用流来构建一个复杂的xml文档,运行后结果如下:

---------ObjectOutputStream # JavaObject--object-stream.Birthday>2010-05-33<byte>22</byte<boolean>true</booleanfloat>22.0<string>hello</string>

三、XML内容转换Java对象

1、 用InputStream将XML文档转换成java对象

* <b>function:</b>用InputStream将XML文档转换成java对象
 * 需要额外的jar xpp3-main.jar
 * @author hoojo
 */
void readXML4InputStream() {
        String s = "<object-stream><com.hoo.entity.Student><id>0</id><name>jack</name>" +
"</com.hoo.entity.Student><com.hoo.entity.Birthday><birthday>2010-05-33</birthday>" +
"</com.hoo.entity.Birthday><byte>22</byte><boolean>true</boolean><float>22.0</float>" +
"<string>hello</string></object-stream>";
"---------ObjectInputStream## XML --> javaObject---------");
        StringReader reader = new StringReader(s);
        in = xstream.createObjectInputStream(reader);
        Student stu = (Student) in.readObject();
        Birthday b = (Birthday) in.readObject();
byte i = in.readByte();
boolean bo = in.readBoolean();
float f = in.readFloat();
        String str = in.readUTF();
        System.out.println(stu);
        System.out.println(b);
        System.out.println(i);
        System.out.println(bo);
        System.out.println(f);
        System.out.println(str);
}

读取后,转换的Java对象,结果如下:

---------ObjectInputStream## XML --> javaObject---------
jack#0#null#null#null
2010-05-33
22
true
22.0
hello

2、 将xml文档转换成Java对象

* <b>function:</b>将XML字符串转换成Java对象
void readXml2Object() {
"-----------Xml >>> Bean--------------");
        Student stu = (Student) xstream.fromXML(xstream.toXML(bean));
        fail(stu.toString());
        List<Student> list = new ArrayList<Student>();
//add
//add
"==========XML >>> List===========");
        List<Student> studetns = (List<Student>) xstream.fromXML(xstream.toXML(list));
"size:" + studetns.size());//3
for (Student s : studetns) {
            fail(s.toString());
"==========XML >>> Map===========");
"size:" + maps.size());//3
        Set<String> key = maps.keySet();
        Iterator<String> iter = key.iterator();
while (iter.hasNext()) {
            String k = iter.next();
            fail(k + ":" + map.get(k));
-----------Xml >>> Bean--------------
jack#1#china#2010-11-22#jack@email.com
==========XML >>> List===========
size:3
jack#1#china#2010-11-22#jack@email.com
tom#2#china#2010-11-22#tom@125.com
jack#0#null#null#null
==========XML >>> Map===========
size:3
No.3:jack#0#null#null#null
No.1:jack#1#china#2010-11-22#jack@email.com
No.2:tom#2#china#2010-11-22#tom@125.com

怎么样,成功的完成XML到JavaBean、List、Map的转换,更多对象转换还需要大家一一尝试。用法类似~这里就不一样赘述。

四、XStream对JSON的支持

xStream对JSON也有非常好的支持,它提供了2个模型驱动。用这2个驱动可以完成Java对象到JSON的相互转换。使用JettisonMappedXmlDriver驱动,将Java对象转换成json,需要添加jettison.jar

1、 用JettisonMappedXmlDriver完成Java对象到JSON的转换

* <b>function:</b>XStream结合JettisonMappedXmlDriver驱动,转换Java对象到JSON
 * 需要添加jettison jar
void writeEntity2JETTSON() {
    failRed("=======JettisonMappedXmlDriver===JavaObject >>>> JaonString=========");
    xstream = new XStream(new JettisonMappedXmlDriver());
    xstream.setMode(XStream.NO_REFERENCES);
    xstream.alias(    fail(xstream.toXML(bean));
=======JettisonMappedXmlDriver===JavaObject >>>> JaonString=========
{"student":{"id":1,128)">"name":"jack",128)">"email":"jack@email.com",128)">"address":"china",128)">"birthday":[{},128)">"2010-11-22"]}}

JSON的转换和XML的转换用法一样,只是创建XStream需要传递一个参数,这个参数就是xml到JSON映射转换的驱动。这里会降到两个驱动,分别是JettisonMappedXmlDriver、JsonHierarchicalStreamDriver。

2、 JsonHierarchicalStreamDriver完成Java对象到JSON的转换

* <b>function:</b>用XStream结合JsonHierarchicalStreamDriver驱动
 * 转换java对象为JSON字符串
void writeEntiry2JSON() {
"======JsonHierarchicalStreamDriver====JavaObject >>>> JaonString=========");
new JsonHierarchicalStreamDriver());
//xstream.setMode(XStream.NO_REFERENCES);
"-------Object >>>> JSON---------");
    fail(xstream.toXML(bean));
//failRed("========JsonHierarchicalStreamDriver==删除根节点=========");
//删除根节点
new JsonHierarchicalStreamDriver() {
public HierarchicalStreamWriter createWriter(Writer out) {
new JsonWriter(out,JsonWriter.DROP_ROOT_MODE);
    });
======JsonHierarchicalStreamDriver====JavaObject >>>> JaonString=========
-------Object >>>> JSON---------
"student": {
"id": 1,
"name": "email": "address": "birthday": {
"birthday": "2010-11-22"
  }
}}
{
"birthday": {
"2010-11-22"
  }
}

使用JsonHierarchicalStreamDriver转换默认会给转换后的对象添加一个根节点,但是在构建JsonHierarchicalStreamDriver驱动的时候,你可以重写createWriter方法,删掉根节点。

看上面的结果,一个是默认带根节点的JSON对象,它只是将类名作为一个属性,将对象作为该属性的一个值。而另一个没有带根属性的JSON就是通过重写createWriter方法完成的。

3、 将List集合转换成JSON字符串

void writeList2JSON() {
    JsonHierarchicalStreamDriver driver = new JsonHierarchicalStreamDriver();
new XStream(driver);
//xstream = new XStream(new JettisonMappedXmlDriver());//转换错误
    List<Student> list = new ArrayList<Student>();
    list.add(bean);    bean =     bean.setAddress(    bean.setEmail(    bean.setId(2);
    bean.setName(    Birthday day =     bean.setBirthday(day);
    fail(xstream.toXML(list));
}

运行后结果如下

##{"list": [
  {
  },monospace; direction:ltr; font-size:10pt; overflow:visible">  {
"id": 2,128)">"tom",128)">"tom@125.com",128)">"id": 0,128)">"jack"
]}
#[
]

上面的list1是使用JsonHierarchicalStreamDriver 转换的,当然你也可以使用JettisonMappedXmlDriver驱动进行转换;用JettisonMappedXmlDriver转换后,你会发现格式不同而且没有根属性

4、 Map转换json

void writeMap2JSON() {
"======JsonHierarchicalStreamDriver==== Map >>>> JaonString=========");
//xstream = new XStream(new JettisonMappedXmlDriver());
    Map<String,monospace; direction:ltr; font-size:10pt; overflow:visible">    map.put(    bean.setBirthday("2010-11-21"));
    fail(xstream.toXML(map));
//failRed("========JsonHierarchicalStreamDriver==删除根节点=========");
//删除根节点
new JsonHierarchicalStreamDriver() {
public HierarchicalStreamWriter createWriter(Writer out) {
    });
======JsonHierarchicalStreamDriver==== Map >>>> JaonString=========
"map": [
  [
    {
  ],monospace; direction:ltr; font-size:10pt; overflow:visible">  [
    {
      }
"2010-11-21"
  ]
]}
[
"jack"
      }
"2010-11-21"
  ]
]

5、 将JSON转换java对象

* <b>function:</b>JsonHierarchicalStreamDriver可以将简单的json字符串转换成java对象,list、map转换不成功;
 * JsonHierarchicalStreamDriver读取JSON字符串到java对象出错
 * @throws JSONException
void readJSON2Object() throws JSONException {
    String json = "{/"student/": {" +
"/"id/": 1," +
"/"name/": /"haha/"," +
"/"email/": /"email/",128)">"/"address/": /"address/",128)">"/"birthday/": {" +
"/"birthday/": /"2010-11-22/"" +
"}" +
"}}";
//JsonHierarchicalStreamDriver读取JSON字符串到java对象出错,但JettisonMappedXmlDriver可以
    fail(xstream.fromXML(json).toString());
//JettisonMappedXmlDriver转换List集合出错,但JsonHierarchicalStreamDriver可以转换正确
//JettisonMappedXmlDriver 转换的字符串 {"list":{"student":[{"id":1,"name":"haha","email":"email","address":"address","birthday":[{},"2010-11-22"]}]},"student":{"id":2,"name":"tom","email":"tom@125.com","address":"china","2010-11-22"]}}
    json = "{/"list/": [{" +
                         "},{" +
"/"id/": 2,128)">"/"name/": /"tom/",128)">"/"email/": /"tom@125.com/",128)">"/"address/": /"china/",128)">"}]}";
    System.out.println(json);//用js转换成功
    List list = (List) xstream.fromXML(json);
    System.out.println(list.size());//0好像转换失败
haha#1#address#2010-11-22#email
"list": [{"haha",128)">"email",128)">"address",128)">"birthday": {"2010-11-22"}},128)">"2010-11-22"}}]}
0

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