xStream完美转换XML、JSON

[code]packagecom.hoo.test;

importjava.io.IOException;

importjava.io.ObjectInputStream;

importjava.io.ObjectOutputStream;

importjava.io.StringReader;

importjava.io.Writer;

importjava.util.ArrayList;

importjava.util.HashMap;

importjava.util.Iterator;

importjava.util.List;

importjava.util.Map;

importjava.util.Set;

importorg.codehaus.jettison.json.JSONException;

importorg.junit.After;

importorg.junit.Before;

importorg.junit.Test;

importcom.hoo.entity.Birthday;

importcom.hoo.entity.Classes;

importcom.hoo.entity.ListBean;

importcom.hoo.entity.Student;

importcom.thoughtworks.xstream.XStream;

importcom.thoughtworks.xstream.io.HierarchicalStreamWriter;

importcom.thoughtworks.xstream.io.json.JettisonMappedXmlDriver;

importcom.thoughtworks.xstream.io.json.JsonHierarchicalStreamDriver;

importcom.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

*@authorhoojo

*@createDateNov27,201012:15:15PM

*@fileXStreamTest.java

*@packagecom.hoo.test

*@projectWebHttpUtils

*@blog
'target='_blank'>http://blog.csdn.net/IBM_hoojo
*@emailhoojo_@126.com
*@version1.0
*/
@SuppressWarnings("unchecked")
publicclassXStreamTest{
privateXStreamxstream=null;
privateObjectOutputStreamout=null;
privateObjectInputStreamin=null;
privateStudentbean=null;
/**
*<b>function:</b>初始化资源准备
*@authorhoojo
*@createDateNov27,201012:16:28PM
*/
@Before
publicvoidinit(){
try{
xstream=newXStream();
//xstream=newXStream(newDomDriver());//需要xpp3jar
}catch(Exceptione){
e.printStackTrace();
}
bean=newStudent();
bean.setAddress("china");
bean.setEmail("jack@email.com");
bean.setId(1);
bean.setName("jack");
Birthdayday=newBirthday();
day.setBirthday("2010-11-22");
bean.setBirthday(day);
}
/**
*<b>function:</b>释放对象资源
*@authorhoojo
*@createDateNov27,201012:16:38PM
*/
@After
publicvoiddestory(){
xstream=null;
bean=null;
try{
if(out!=null){
out.flush();
out.close();
}
if(in!=null){
in.close();
}
}catch(IOExceptione){
e.printStackTrace();
}
System.gc();
}
publicfinalvoidfail(Stringstring){
System.out.println(string);
}
publicfinalvoidfailRed(Stringstring){
System.err.println(string);
}
}
[/code]
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

[code]packagecom.hoo.entity;
publicclassStudent{
privateintid;
privateStringname;
privateStringemail;
privateStringaddress;
privateBirthdaybirthday;
//getter、setter
publicStringtoString(){
returnthis.name+"#"+this.id+"#"+this.address+"#"+this.birthday+"#"+this.email;
}
}
[/code]

二、Java转换成XML
1、JavaBean转换XM
[code]/**
*<b>function:</b>Java对象转换成XML字符串
*@authorhoojo
*@createDateNov27,201012:19:01PM
*/
@Test
publicvoidwriteBean2XML(){
try{
fail("------------Bean->XML------------");
fail(xstream.toXML(bean));
fail("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");
//xstream.aliasField("生日",Birthday.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","com.hoo.entity");
fail(xstream.toXML(bean));
}catch(Exceptione){
e.printStackTrace();
}
}
[/code]
看结果中的第一份xml内容，是没有经过然后修改或重命名的文档，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：
[code]------------Bean->XML------------
<com.hoo.entity.Student>
<id>1</id>
<name>jack</name>
<email>jack@email.com</email>
<address>china</address>
<birthday>
<birthday>2010-11-22</birthday>
</birthday>
</com.hoo.entity.Student>
重命名后的XML
<hoo.Student>
<id>1</id>
<name>jack</name>
<邮件>jack@email.com</邮件>
<address>china</address>
<birthday>
<birthday>2010-11-22</birthday>
</birthday>
</hoo.Student>
[/code]
2、将List集合转换成xml文档
[code]/**
*<b>function:</b>将Java的List集合转换成XML对象
*@authorhoojo
*@createDateNov27,201012:20:07PM
*/
@Test
publicvoidwriteList2XML(){
try{
//修改元素名称
xstream.alias("beans",ListBean.class);
xstream.alias("student",Student.class);
fail("----------List-->XML----------");
ListBeanlistBean=newListBean();
listBean.setName("thisisaListCollection");
List<Object>list=newArrayList<Object>();
list.add(bean);
list.add(bean);//引用bean
//list.add(listBean);//引用listBean，父元素
bean=newStudent();
bean.setAddress("china");
bean.setEmail("tom@125.com");
bean.setId(2);
bean.setName("tom");
Birthdayday=newBirthday("2010-11-22");
bean.setBirthday(day);
list.add(bean);
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.class,"name");
xstream.useAttributeFor(Birthday.class,"birthday");
//修改属性的name
xstream.aliasAttribute("姓名","name");
xstream.aliasField("生日",Birthday.class,"birthday");
fail(xstream.toXML(listBean));
}catch(Exceptione){
e.printStackTrace();
}
}
[/code]
上面的代码运行后，结果如下：
[code]----------List-->XML----------
<beansid="1">
<name>thisisaListCollection</name>
<listid="2">
<studentid="3"姓名="jack">
<id>1</id>
<email>jack@email.com</email>
<address>china</address>
<birthdayid="4"生日="2010-11-22"/>
</student>
<studentreference="3"/>
<studentid="5"姓名="tom">
<id>2</id>
<email>tom@125.com</email>
<address>china</address>
<birthdayid="6"生日="2010-11-22"/>
</student>
</list>
</beans>
[/code]
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，<studentreference="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元素节点的属性中显示。
如：<student><name>hoojo</name></student>
设置好后就是这样的结果：<studentname=”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

[code]packagecom.hoo.entity;
importjava.util.Arrays;
importjava.util.Calendar;
importjava.util.GregorianCalendar;
importjava.util.List;
importcom.thoughtworks.xstream.annotations.XStreamAlias;
importcom.thoughtworks.xstream.annotations.XStreamAsAttribute;
importcom.thoughtworks.xstream.annotations.XStreamConverter;
importcom.thoughtworks.xstream.annotations.XStreamImplicit;
importcom.thoughtworks.xstream.annotations.XStreamOmitField;
@XStreamAlias("class")
publicclassClasses{
/*
*设置属性显示
*/
@XStreamAsAttribute
@XStreamAlias("名称")
privateStringname;
/*
*忽略
*/
@XStreamOmitField
privateintnumber;
@XStreamImplicit(itemFieldName="Students")
privateList<Student>students;
@SuppressWarnings("unused")
@XStreamConverter(SingleValueCalendarConverter.class)
privateCalendarcreated=newGregorianCalendar();
publicClasses(){}
publicClasses(Stringname,Student...stu){
this.name=name;
this.students=Arrays.asList(stu);
}
//getter、setter
}
[/code]
SingleValueCalendarConverter.java这个是一个类型转换器

[code]packagecom.hoo.entity;
importjava.util.Calendar;
importjava.util.Date;
importjava.util.GregorianCalendar;
importcom.thoughtworks.xstream.converters.Converter;
importcom.thoughtworks.xstream.converters.MarshallingContext;
importcom.thoughtworks.xstream.converters.UnmarshallingContext;
importcom.thoughtworks.xstream.io.HierarchicalStreamReader;
importcom.thoughtworks.xstream.io.HierarchicalStreamWriter;
publicclassSingleValueCalendarConverterimplementsConverter{
publicvoidmarshal(Objectsource,HierarchicalStreamWriterwriter,
MarshallingContextcontext){
Calendarcalendar=(Calendar)source;
writer.setValue(String.valueOf(calendar.getTime().getTime()));
}
publicObjectunmarshal(HierarchicalStreamReaderreader,
UnmarshallingContextcontext){
GregorianCalendarcalendar=newGregorianCalendar();
calendar.setTime(newDate(Long.parseLong(reader.getValue())));
returncalendar;
}
@SuppressWarnings("unchecked")
publicbooleancanConvert(Classtype){
returntype.equals(GregorianCalendar.class);
}
}
[/code]
再看看测试用例代码
[code]@Test
publicvoidwriteList2XML4Annotation(){
try{
failRed("---------annotationBean-->XML---------");
Studentstu=newStudent();
stu.setName("jack");
Classesc=newClasses("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);
xstream.alias("student",Student.class);
fail(xstream.toXML(c));
}catch(Exceptione){
e.printStackTrace();
}
}
[/code]
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：

[code]---------annotationBean-->XML---------
<com.hoo.entity.Classes>
<name>一班</name>
<number>2</number>
<studentsclass="java.util.Arrays$ArrayList">
<aclass="student-array">
<student>
<id>1</id>
<name>jack</name>
<email>jack@email.com</email>
<address>china</address>
<birthday>
<birthday>2010-11-22</birthday>
</birthday>
</student>
<student>
<id>0</id>
<name>jack</name>
</student>
</a>
</students>
<created>
<time>1303292056718</time>
<timezone>Asia/Shanghai</timezone>
</created>
</com.hoo.entity.Classes>
[/code]
当启用annotation后xstream.processAnnotations(Classes.class)，结果如下：

[code]---------annotationBean-->XML---------
<class名称="一班">
<Students>
<id>1</id>
<name>jack</name>
<email>jack@email.com</email>
<address>china</address>
<birthday>
<birthday>2010-11-22</birthday>
</birthday>
</Students>
<Students>
<id>0</id>
<name>jack</name>
</Students>
<created>1303292242937</created>
</class>
[/code]
4、Map集合转换xml文档
[code]/**
*<b>function:</b>JavaMap集合转XML
*@authorhoojo
*@createDateNov27,20101:13:26PM
*/
@Test
publicvoidwriteMap2XML(){
try{
failRed("---------Map-->XML---------");
Map<String,Student>map=newHashMap<String,Student>();
map.put("No.1",bean);//put
bean=newStudent();
bean.setAddress("china");
bean.setEmail("tom@125.com");
bean.setId(2);
bean.setName("tom");
Birthdayday=newBirthday("2010-11-22");
bean.setBirthday(day);
map.put("No.2",bean);//put
bean=newStudent();
bean.setName("jack");
map.put("No.3",bean);//put
xstream.alias("student",Student.class);
xstream.alias("key",String.class);
xstream.useAttributeFor(Student.class,"id");
xstream.useAttributeFor("birthday",String.class);
fail(xstream.toXML(map));
}catch(Exceptione){
e.printStackTrace();
}
}
[/code]
运行后结果如下：

[code]---------Map-->XML---------
<map>
<entry>
<key>No.3</key>
<studentid="0">
<name>jack</name>
</student>
</entry>
<entry>
<key>No.1</key>
<studentid="1">
<name>jack</name>
<email>jack@email.com</email>
<address>china</address>
<birthdaybirthday="2010-11-22"/>
</student>
</entry>
<entry>
<key>No.2</key>
<studentid="2">
<name>tom</name>
<email>tom@125.com</email>
<address>china</address>
<birthdaybirthday="2010-11-22"/>
</student>
</entry>
</map>
[/code]
5、用OutStream输出流写XML
[code]/**
*<b>function:</b>用OutStream输出流写XML
*@authorhoojo
*@createDateNov27,20101:13:48PM
*/
@Test
publicvoidwriteXML4OutStream(){
try{
out=xstream.createObjectOutputStream(System.out);
Studentstu=newStudent();
stu.setName("jack");
Classesc=newClasses("一班",bean,stu);
c.setNumber(2);
failRed("---------ObjectOutputStream#JavaObject-->XML---------");
out.writeObject(stu);
out.writeObject(newBirthday("2010-05-33"));
out.write(22);//byte
out.writeBoolean(true);
out.writeFloat(22.f);
out.writeUTF("hello");
}catch(Exceptione){
e.printStackTrace();
}
}
[/code]
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：

[code]---------ObjectOutputStream#JavaObject-->XML---------
<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>
[/code]

三、XML内容转换Java对象
1、用InputStream将XML文档转换成java对象
[code]/**
*<b>function:</b>用InputStream将XML文档转换成java对象
*需要额外的jarxpp3-main.jar
*@authorhoojo
*@createDateNov27,20101:14:52PM
*/
@Test
publicvoidreadXML4InputStream(){
try{
Strings="<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>";
failRed("---------ObjectInputStream##XML-->javaObject---------");
StringReaderreader=newStringReader(s);
in=xstream.createObjectInputStream(reader);
Studentstu=(Student)in.readObject();
Birthdayb=(Birthday)in.readObject();
bytei=in.readByte();
booleanbo=in.readBoolean();
floatf=in.readFloat();
Stringstr=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);
}catch(Exceptione){
e.printStackTrace();
}
}
[/code]
读取后，转换的Java对象，结果如下：

[code]---------ObjectInputStream##XML-->javaObject---------
jack#0#null#null#null
2010-05-33
22
true
22.0
hello
[/code]
2、将xml文档转换成Java对象
[code]/**
*<b>function:</b>将XML字符串转换成Java对象
*@authorhoojo
*@createDateNov27,20102:39:06PM
*/
@Test
publicvoidreadXml2Object(){
try{
failRed("-----------Xml>>>Bean--------------");
Studentstu=(Student)xstream.fromXML(xstream.toXML(bean));
fail(stu.toString());
List<Student>list=newArrayList<Student>();
list.add(bean);//add
Map<String,Student>map=newHashMap<String,Student>();
map.put("No.1",bean);//put
bean=newStudent();
bean.setAddress("china");
bean.setEmail("tom@125.com");
bean.setId(2);
bean.setName("tom");
Birthdayday=newBirthday("2010-11-22");
bean.setBirthday(day);
list.add(bean);//add
map.put("No.2",bean);//put
bean=newStudent();
bean.setName("jack");
list.add(bean);//add
map.put("No.3",bean);//put
failRed("==========XML>>>List===========");
List<Student>studetns=(List<Student>)xstream.fromXML(xstream.toXML(list));
fail("size:"+studetns.size());//3
for(Students:studetns){
fail(s.toString());
}
failRed("==========XML>>>Map===========");
Map<String,Student>maps=(Map<String,Student>)xstream.fromXML(xstream.toXML(map));
fail("size:"+maps.size());//3
Set<String>key=maps.keySet();
Iterator<String>iter=key.iterator();
while(iter.hasNext()){
Stringk=iter.next();
fail(k+":"+map.get(k));
}
}catch(Exceptione){
e.printStackTrace();
}
}
[/code]
运行后结果如下：

[code]-----------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
[/code]
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
[code]/**
*<b>function:</b>XStream结合JettisonMappedXmlDriver驱动，转换Java对象到JSON
*需要添加jettisonjar
*@authorhoojo
*@createDateNov27,20101:23:18PM
*/
@Test
publicvoidwriteEntity2JETTSON(){
failRed("=======JettisonMappedXmlDriver===JavaObject>>>>JaonString=========");
xstream=newXStream(newJettisonMappedXmlDriver());
xstream.setMode(XStream.NO_REFERENCES);
xstream.alias("student",Student.class);
fail(xstream.toXML(bean));
}
[/code]
运行后结果如下：

[code]=======JettisonMappedXmlDriver===JavaObject>>>>JaonString=========
{"student":{"id":1,"name":"jack","email":"jack@email.com","address":"china","birthday":[{},"2010-11-22"]}}
[/code]
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
[code]/**
*<b>function:</b>用XStream结合JsonHierarchicalStreamDriver驱动
*转换java对象为JSON字符串
*@authorhoojo
*@createDateNov27,20101:16:46PM
*/
@Test
publicvoidwriteEntiry2JSON(){
failRed("======JsonHierarchicalStreamDriver====JavaObject>>>>JaonString=========");
xstream=newXStream(newJsonHierarchicalStreamDriver());
//xstream.setMode(XStream.NO_REFERENCES);
xstream.alias("student",Student.class);
failRed("-------Object>>>>JSON---------");
fail(xstream.toXML(bean));
//failRed("========JsonHierarchicalStreamDriver==删除根节点=========");
//删除根节点
xstream=newXStream(newJsonHierarchicalStreamDriver(){
publicHierarchicalStreamWritercreateWriter(Writerout){
returnnewJsonWriter(out,JsonWriter.DROP_ROOT_MODE);
}
});
//xstream.setMode(XStream.NO_REFERENCES);
xstream.alias("student",Student.class);
fail(xstream.toXML(bean));
}
[/code]
运行后结果如下：

[code]======JsonHierarchicalStreamDriver====JavaObject>>>>JaonString=========
-------Object>>>>JSON---------
{"student":{
"id":1,
"name":"jack",
"email":"jack@email.com",
"address":"china",
"birthday":{
"birthday":"2010-11-22"
}
}}
{
"id":1,
"name":"jack",
"email":"jack@email.com",
"address":"china",
"birthday":{
"birthday":"2010-11-22"
}
}
[/code]
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
[code]@Test
publicvoidwriteList2JSON(){
failRed("======JsonHierarchicalStreamDriver====JavaObject>>>>JaonString=========");
JsonHierarchicalStreamDriverdriver=newJsonHierarchicalStreamDriver();
xstream=newXStream(driver);
//xstream=newXStream(newJettisonMappedXmlDriver());//转换错误
//xstream.setMode(XStream.NO_REFERENCES);
xstream.alias("student",Student.class);
List<Student>list=newArrayList<Student>();
list.add(bean);//add
bean=newStudent();
bean.setAddress("china");
bean.setEmail("tom@125.com");
bean.setId(2);
bean.setName("tom");
Birthdayday=newBirthday("2010-11-22");
bean.setBirthday(day);
list.add(bean);//add
bean=newStudent();
bean.setName("jack");
list.add(bean);//add
fail(xstream.toXML(list));
//failRed("========JsonHierarchicalStreamDriver==删除根节点=========");
//删除根节点
xstream=newXStream(newJsonHierarchicalStreamDriver(){
publicHierarchicalStreamWritercreateWriter(Writerout){
returnnewJsonWriter(out,JsonWriter.DROP_ROOT_MODE);
}
});
xstream.alias("student",Student.class);
fail(xstream.toXML(list));
}
[/code]
运行后结果如下

[code]======JsonHierarchicalStreamDriver====JavaObject>>>>JaonString=========
##{"list":[
{
"id":1,
"name":"jack",
"email":"jack@email.com",
"address":"china",
"birthday":{
"birthday":"2010-11-22"
}
},
{
"id":2,
"name":"tom",
"email":"tom@125.com",
"address":"china",
"birthday":{
"birthday":"2010-11-22"
}
},
{
"id":0,
"name":"jack"
}
]}
#[
{
"id":1,
"name":"jack",
"email":"jack@email.com",
"address":"china",
"birthday":{
"birthday":"2010-11-22"
}
},
{
"id":2,
"name":"tom",
"email":"tom@125.com",
"address":"china",
"birthday":{
"birthday":"2010-11-22"
}
},
{
"id":0,
"name":"jack"
}
]
[/code]
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
[code]@Test
publicvoidwriteMap2JSON(){
failRed("======JsonHierarchicalStreamDriver====Map>>>>JaonString=========");
xstream=newXStream(newJsonHierarchicalStreamDriver());
//xstream=newXStream(newJettisonMappedXmlDriver());
xstream.alias("student",Student.class);
Map<String,Student>map=newHashMap<String,Student>();
map.put("No.1",bean);//put
bean=newStudent();
bean.setAddress("china");
bean.setEmail("tom@125.com");
bean.setId(2);
bean.setName("tom");
bean.setBirthday(newBirthday("2010-11-21"));
map.put("No.2",bean);//put
bean=newStudent();
bean.setName("jack");
map.put("No.3",bean);//put
fail(xstream.toXML(map));
//failRed("========JsonHierarchicalStreamDriver==删除根节点=========");
//删除根节点
xstream=newXStream(newJsonHierarchicalStreamDriver(){
publicHierarchicalStreamWritercreateWriter(Writerout){
returnnewJsonWriter(out,JsonWriter.DROP_ROOT_MODE);
}
});
xstream.alias("student",Student.class);
fail(xstream.toXML(map));
}
[/code]
运行后结果如下：

[code]======JsonHierarchicalStreamDriver====Map>>>>JaonString=========
{"map":[
[
"No.3",
{
"id":0,
"name":"jack"
}
],
[
"No.1",
{
"id":1,
"name":"jack",
"email":"jack@email.com",
"address":"china",
"birthday":{
"birthday":"2010-11-22"
}
}
],
[
"No.2",
{
"id":2,
"name":"tom",
"email":"tom@125.com",
"address":"china",
"birthday":{
"birthday":"2010-11-21"
}
}
]
]}
[
[
"No.3",
{
"id":0,
"name":"jack"
}
],
[
"No.1",
{
"id":1,
"name":"jack",
"email":"jack@email.com",
"address":"china",
"birthday":{
"birthday":"2010-11-22"
}
}
],
[
"No.2",
{
"id":2,
"name":"tom",
"email":"tom@125.com",
"address":"china",
"birthday":{
"birthday":"2010-11-21"
}
}
]
]
[/code]
5、将JSON转换java对象
[code]/**
*<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
*@authorhoojo
*@createDateNov27,20101:22:26PM
*@throwsJSONException
*/
@Test
publicvoidreadJSON2Object()throwsJSONException{
Stringjson="{\"student\":{"+
"\"id\":1,"+
"\"name\":\"haha\","+
"\"email\":\"email\","+
"\"address\":\"address\","+
"\"birthday\":{"+
"\"birthday\":\"2010-11-22\""+
"}"+
"}}";
//JsonHierarchicalStreamDriver读取JSON字符串到java对象出错，但JettisonMappedXmlDriver可以
xstream=newXStream(newJettisonMappedXmlDriver());
xstream.alias("student",Student.class);
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","birthday":[{},"2010-11-22"]}}
json="{\"list\":[{"+
"\"id\":1,"+
"\"name\":\"haha\","+
"\"email\":\"email\","+
"\"address\":\"address\","+
"\"birthday\":{"+
"\"birthday\":\"2010-11-22\""+
"}"+
"},{"+
"\"id\":2,"+
"\"name\":\"tom\","+
"\"email\":\"tom@125.com\","+
"\"address\":\"china\","+
"\"birthday\":{"+
"\"birthday\":\"2010-11-22\""+
"}"+
"}]}";
System.out.println(json);//用js转换成功
Listlist=(List)xstream.fromXML(json);
System.out.println(list.size());//0好像转换失败
}
[/code]
运行后结果如下：
[code]haha#1#address#2010-11-22#email
{"list":[{"id":1,"name":"haha","email":"email","address":"address","birthday":{"birthday":"2010-11-22"}},
{"id":2,"name":"tom","email":"tom@125.com","address":"china","birthday":{"birthday":"2010-11-22"}}]}
0
[/code]
JSON到Java的转换是fromXML方法。