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xStream可以轻易的将Java对象和xml文档相互转换

2016-03-28 15:49 666 查看
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:/article/4791846.html

以及Jackson这个框架,在线博文:/article/4791847.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

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[/code]
*@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);

}

}


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

packagecom.hoo.entity;


publicclassStudent{

privateintid;

privateStringname;

privateStringemail;

privateStringaddress;

privateBirthdaybirthday;

//getter、setter

publicStringtoString(){

returnthis.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

*@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();

}

}


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:

------------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>


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

*@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();

}

}


上面的代码运行后,结果如下:

----------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>


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

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

}


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

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);

}

}


再看看测试用例代码

@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();

}

}


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:

---------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>


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

---------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>


4、Map集合转换xml文档

/**

*<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();

}

}


运行后结果如下:

---------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>


5、用OutStream输出流写XML

/**

*<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();

}

}


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-->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>


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();

}

}


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

*@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();

}

}


运行后结果如下:

-----------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));

}


运行后结果如下:

=======JettisonMappedXmlDriver===JavaObject>>>>JaonString=========

{"student":{"id":1,"name":"jack","email":"jack@email.com","address":"china","birthday":[{},"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

*@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));

}


运行后结果如下:

======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"

}

}


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

@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));

}


运行后结果如下

======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"

}

]


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

@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));

}


运行后结果如下:

======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"

}

}

]

]


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

*@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

}


运行后结果如下:

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


JSON到Java的转换是fromXML方法。
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