xStream完美转换XML、JSON
2016-07-18 16:54
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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
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:
以及Jackson这个框架,在线博文:
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:
官方的示例很全,官方参考示例:
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*/@Beforepublicvoidinit(){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*/@Afterpublicvoiddestory(){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JavaBeanpackagecom.hoo.entity;publicclassStudent{privateintid;privateStringname;privateStringemail;privateStringaddress;privateBirthdaybirthday;//getter、setterpublicStringtoString(){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*/@TestpublicvoidwriteBean2XML(){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*/@TestpublicvoidwriteList2XML(){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namexstream.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*/@XStreamOmitFieldprivateintnumber;@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@TestpublicvoidwriteList2XML4Annotation(){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*/@TestpublicvoidwriteMap2XML(){try{failRed("---------Map-->XML---------");Map<String,Student>map=newHashMap<String,Student>();map.put("No.1",bean);//putbean=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);//putbean=newStudent();bean.setName("jack");map.put("No.3",bean);//putxstream.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*/@TestpublicvoidwriteXML4OutStream(){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);//byteout.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*/@TestpublicvoidreadXML4InputStream(){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#null2010-05-3322true22.0hello
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*/@TestpublicvoidreadXml2Object(){try{failRed("-----------Xml>>>Bean--------------");Studentstu=(Student)xstream.fromXML(xstream.toXML(bean));fail(stu.toString());List<Student>list=newArrayList<Student>();list.add(bean);//addMap<String,Student>map=newHashMap<String,Student>();map.put("No.1",bean);//putbean=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);//addmap.put("No.2",bean);//putbean=newStudent();bean.setName("jack");list.add(bean);//addmap.put("No.3",bean);//putfailRed("==========XML>>>List===========");List<Student>studetns=(List<Student>)xstream.fromXML(xstream.toXML(list));fail("size:"+studetns.size());//3for(Students:studetns){fail(s.toString());}failRed("==========XML>>>Map===========");Map<String,Student>maps=(Map<String,Student>)xstream.fromXML(xstream.toXML(map));fail("size:"+maps.size());//3Set<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:3jack#1#china#2010-11-22#jack@email.comtom#2#china#2010-11-22#tom@125.comjack#0#null#null#null==========XML>>>Map===========size:3No.3:jack#0#null#null#nullNo.1:jack#1#china#2010-11-22#jack@email.comNo.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*/@TestpublicvoidwriteEntity2JETTSON(){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*/@TestpublicvoidwriteEntiry2JSON(){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@TestpublicvoidwriteList2JSON(){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);//addbean=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);//addbean=newStudent();bean.setName("jack");list.add(bean);//addfail(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@TestpublicvoidwriteMap2JSON(){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);//putbean=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);//putbean=newStudent();bean.setName("jack");map.put("No.3",bean);//putfail(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*/@TestpublicvoidreadJSON2Object()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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