gson使用在android使用例子-优快云博客

转自：http://smallbee.iteye.com/blog/1066993

 
  //转换器 
 GsonBuilderbuilder=newGsonBuilder(); 
 //不转换没有@Expose注解的字段 
 builder.excludeFieldsWithoutExposeAnnotation(); 
 Gsongson=builder.create(); 
  
 //1、对象转string 
 Studentstu=newStudent(); 
 stu.setStudentId(333); 
 stu.setStudentName("qqq"); 
 StringstuStr=gson.toJson(stu); 
 System.out.println(stuStr);//{"studentName":"qqq","studentId":333} 
  
  
 //2、string转对象 
 Studentuser2=gson.fromJson(stuStr,Student.class); 
 System.out.println(user2); 
 StringstuTemp="{\"studentName\":\"qqq2\",\"studentId\":3335}"; 
 Studentuser4=gson.fromJson(stuTemp,Student.class); 
 System.out.println(user4); 
  
 //3、对象List转string 
 List<Student>testBeanList=newArrayList<Student>(); 
 StudenttestBean=newStudent(); 
 testBean.setStudentId(555); 
 testBean.setStudentName("552"); 
 testBeanList.add(testBean); 
  
 //GsongsonList=newGson(); 
 Typetype=newTypeToken<List<Student>>(){}.getType();//指定集合对象属性 
 StringbeanListToJson=gson.toJson(testBeanList,type); 
 System.out.println(beanListToJson);//[{"studentName":"552","studentId":555}] 
  
 //集合string转对象list 
 List<Student>testBeanListFromJson=gson.fromJson(beanListToJson,type); 
 System.out.println(testBeanListFromJson);//[555:552] 
  
 //4、集合如果不指定类型默认为String 
 List<String>testList=newArrayList<String>(); 
 testList.add("first"); 
 testList.add("second"); 
 StringlistToJson=gson.toJson(testList); 
 System.out.println(listToJson);//["first","second"] 
  
 //5、集合字符串转回来需要指定类型 
 List<String>testList2=(List<String>)gson.fromJson(listToJson, 
 newTypeToken<List<String>>(){ 
 }.getType()); 
 System.out.println(testList2); 
  
 //6、将HashMap字符串转换为JSON 
 Map<String,String>testMap=newHashMap<String,String>(); 
 testMap.put("id","id.first"); 
 testMap.put("name","name.second"); 
 StringmapToJson=gson.toJson(testMap); 
 System.out.println(mapToJson);//{"id":"id.first","name":"name.second"} 
 //7、stringMap转对象 
 Map<String,String>userMap2=(Map<String,String>)gson.fromJson(mapToJson, 
 newTypeToken<Map<String,String>>(){ 
 }.getType()); 
 System.out.println(userMap2);//{id=id.first,name=name.second} 
  
 //8、对象含有普通对象、集合、map情况 
 Studentuser1=newStudent(); 
 user1.setStudentId(1001); 
 user1.setStudentName("张三"); 
  
 Studentuser3=newStudent(); 
 user3.setStudentId(1002); 
 user3.setStudentName("李四"); 
  
 Map<String,Student>userMap=newHashMap<String,Student>(); 
 userMap.put("user1",user1); 
 userMap.put("user3",user3); 
  
 List<Student>userList=newArrayList<Student>(); 
 userList.add(user1); 
 userList.add(user3); 
  
 TeachergroupBean=newTeacher(); 
 groupBean.setStudent(user1); 
 groupBean.setStus(userList); 
 groupBean.setMap((HashMap)userMap); 
 //groupBean.setUserList(userList); 
 GsongsonGroup=newGson(); 
  
 StringsGroupBean=gsonGroup.toJson(groupBean,newTypeToken<Teacher>(){ 
 }.getType()); 
 System.out.println(sGroupBean); 
 /*{"stus":[{"studentName":"张三","studentId":1001},{"studentName":"李四","studentId":1002}],"student":{"studentName":"张三","studentId":1001},"map":{"user3":{"studentName":"李四","studentId":1002},"user1":{"studentName":"张三","studentId":1001}},"id":0,"age":0}*/ 
 

    Java代码 
    
  
 //9、复杂对象string转对象 
 TeachergroupBean2=(Teacher)gson.fromJson(sGroupBean, 
 newTypeToken<Teacher>(){ 
 }.getType()); 
 System.out.println(groupBean2); 

    Java代码 
    
  
 packagecom.andtools; 
  
 importcom.google.gson.annotations.Expose; 
  
 publicclassStudent{ 
 @Expose 
 privateStringstudentName; 
 @Expose 
 privateintstudentId; 
 publicStudent(){} 
 publicStudent(intstudentId,StringstudentName){ 
 this.setStudentId(studentId); 
 this.setStudentName(studentName); 
 } 
 publicStringtoString(){ 
 returnthis.getStudentId()+":"+this.getStudentName(); 
 } 
 publicStringgetStudentName(){ 
 returnstudentName; 
 } 
 publicvoidsetStudentName(StringstudentName){ 
 this.studentName=studentName; 
 } 
 publicintgetStudentId(){ 
 returnstudentId; 
 } 
 publicvoidsetStudentId(intstudentId){ 
 this.studentId=studentId; 
 } 
  
 } 

    Java代码 
    
  
 packagecom.andtools; 
  
 importjava.util.HashMap; 
 importjava.util.List; 
 importjava.util.Map; 
  
 importcom.google.gson.annotations.Expose; 
  
 publicclassTeacher{ 
 @Expose 
 privateintid; 
 @Expose 
 privateStringname; 
 @Expose 
 privateintage; 
 @Expose 
 privateStudentstudent; 
 @Expose 
 privateListstus; 
 @Expose 
 privateHashMapmap; 
 publicStringtoString(){ 
 returnthis.getId()+":"+this.getName()+":"+this.getAge()+":"+this.getStudent().toString()+":"+this.getStus()+":"+this.getMap(); 
 } 
 publicintgetId(){ 
 returnid; 
 } 
 publicvoidsetId(intid){ 
 this.id=id; 
 } 
 publicStringgetName(){ 
 returnname; 
 } 
 publicvoidsetName(Stringname){ 
 this.name=name; 
 } 
 publicintgetAge(){ 
 returnage; 
 } 
 publicvoidsetAge(intage){ 
 this.age=age; 
 } 
 publicStudentgetStudent(){ 
 returnstudent; 
 } 
 publicvoidsetStudent(Studentstudent){ 
 this.student=student; 
 } 
 publicListgetStus(){ 
 returnstus; 
 } 
 publicvoidsetStus(Liststus){ 
 this.stus=stus; 
 } 
 publicHashMapgetMap(){ 
 returnmap; 
 } 
 publicvoidsetMap(HashMapmap){ 
 this.map=map; 
 } 
  
 }  