Android開發_Gson解析

//轉換器          GsonBuilder builder = new GsonBuilder();           // 不轉換沒有 @Expose 註解的欄位           builder.excludeFieldsWithoutExposeAnnotation();          Gson gson = builder.create();                     //1、對象轉string          Student stu = new Student();          stu.setStudentId(333);          stu.setStudentName("qqq");          String stuStr = gson.toJson(stu);          System.out.println(stuStr); //{"studentName":"qqq","studentId":333}                              //2、string轉對象          Student user2 = gson.fromJson(stuStr, Student.class);           System.out.println(user2);           String stuTemp = "{\"studentName\":\"qqq2\",\"studentId\":3335}";          Student user4 = gson.fromJson(stuTemp, Student.class);           System.out.println(user4);             //3、對象List轉string          List<Student> testBeanList = new ArrayList<Student>();           Student testBean = new Student();           testBean.setStudentId(555);          testBean.setStudentName("552");          testBeanList.add(testBean);                     //Gson gsonList = new Gson();           Type type = new TypeToken<List<Student>>(){}.getType();  //指定集合對象屬性          String beanListToJson = gson.toJson(testBeanList, type);           System.out.println(beanListToJson); //[{"studentName":"552","studentId":555}]             //集合string轉對象list          List<Student> testBeanListFromJson = gson.fromJson(beanListToJson, type);           System.out.println(testBeanListFromJson); //[555:552]            //4、集合如果不指定類型 預設為String          List<String> testList = new ArrayList<String>();           testList.add("first");           testList.add("second");           String listToJson = gson.toJson(testList);           System.out.println(listToJson); //["first","second"]                     //5、集合字串轉回來需要指定類型          List<String> testList2 = (List<String>) gson.fromJson(listToJson,             new TypeToken<List<String>>() {             }.getType());           System.out.println(testList2);             //6、 將HashMap字串轉換為 JSON           Map<String, String> testMap = new HashMap<String, String>();           testMap.put("id", "id.first");           testMap.put("name", "name.second");           String mapToJson = gson.toJson(testMap);           System.out.println(mapToJson); //{"id":"id.first","name":"name.second"}          //7、stringMap轉對象          Map<String, String> userMap2 = (Map<String, String>) gson.fromJson(mapToJson,                   new TypeToken<Map<String, String>>() {               }.getType());           System.out.println(userMap2); //{id=id.first, name=name.second}             //8、對象含有普通對象、集合、map情況          Student user1 = new Student();           user1.setStudentId(1001);           user1.setStudentName("張三");                     Student user3 = new Student();           user3.setStudentId(1002);           user3.setStudentName("李四");                     Map<String, Student> userMap = new HashMap<String, Student>();           userMap.put("user1", user1);           userMap.put("user3", user3);                     List<Student> userList = new ArrayList<Student>();           userList.add(user1);           userList.add(user3);                     Teacher groupBean = new Teacher();           groupBean.setStudent(user1);          groupBean.setStus(userList);          groupBean.setMap((HashMap)userMap);          //groupBean.setUserList(userList);           Gson gsonGroup = new Gson();             String sGroupBean = gsonGroup.toJson(groupBean, new TypeToken<Teacher>() {               }.getType());           System.out.println(sGroupBean);           /*{"stus":[{"studentName":"張三","studentId":1001},{"studentName":"李四","studentId":1002}],"student":{"studentName":"張三","studentId":1001},"map":{"user3":{"studentName":"李四","studentId":1002},"user1":{"studentName":"張三","studentId":1001}},"id":0,"age":0}*/  Java代碼  //9、複雜物件string轉對象  Teacher groupBean2 = (Teacher) gson.fromJson(sGroupBean,      new TypeToken<Teacher>() {      }.getType());   System.out.println(groupBean2);    Java代碼  package com.andtools;    import com.google.gson.annotations.Expose;    public class Student {      @Expose      private String studentName;      @Expose      private int studentId;      public Student(){}      public Student(int studentId,String studentName){          this.setStudentId(studentId);          this.setStudentName(studentName);      }      public String toString(){          return this.getStudentId() + ":" + this.getStudentName();      }      public String getStudentName() {          return studentName;      }      public void setStudentName(String studentName) {          this.studentName = studentName;      }      public int getStudentId() {          return studentId;      }      public void setStudentId(int studentId) {          this.studentId = studentId;      }        }   Java代碼  package com.andtools;    import java.util.HashMap;  import java.util.List;  import java.util.Map;    import com.google.gson.annotations.Expose;    public class Teacher {      @Expose      private int id;      @Expose      private String name;      @Expose      private int age;      @Expose      private Student student;      @Expose      private List stus;      @Expose      private HashMap map;      public String toString(){          return this.getId()+":"+this.getName()+":"+this.getAge() +":"+ this.getStudent().toString() + ":" + this.getStus() + ":" + this.getMap();      }      public int getId() {          return id;      }      public void setId(int id) {          this.id = id;      }      public String getName() {          return name;      }      public void setName(String name) {          this.name = name;      }      public int getAge() {          return age;      }      public void setAge(int age) {          this.age = age;      }      public Student getStudent() {          return student;      }      public void setStudent(Student student) {          this.student = student;      }      public List getStus() {          return stus;      }      public void setStus(List stus) {          this.stus = stus;      }      public HashMap getMap() {          return map;      }      public void setMap(HashMap map) {          this.map = map;      }        }