JSON

* {} 大括号表示对象，[] 方括号表示数组或集合
* 单个对象用JsonObject

Student2 stu = new Student2(1, "张三", 20);

// 生成json字符串。
JSONObject obj = new JSONObject(stu);
System.out.println(obj.toString());

* 多个对象用JsonArray

List<Student2> list = new ArrayList<Student2>();
for(int i=0;i<5;i++){
    Student2 stu = new Student2(i,"aa"+i,20+i);
    list.add(stu);
}
//创建json字符串。
JSONArray array = new JSONArray(list);
System.out.println(array.toString());

JSON生成

// 1:{"id":1,"age":20,"name":"张三"}
public static String fun1(){
    Student stu = new Student(1,"zhangsan",20);
    JSONObject obj = new JSONObject(stu);
    return obj.toString();
}

// 2:{"student":{"id":1,"age":20,"name":"张三"}}
public static String fun2(){
    Student stu = new Student(1,"zhangsan",20);
    JSONObject obj = new JSONObject(stu);
    JSONObject obj2 = new JSONObject();
    try {
        obj2.put("student", obj);
    } catch (JSONException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    return obj2.toString();
}

// 3:{"student":{"id":1,"age":20,"name":"张三"},"class_name":"and1510"}
public static String fun3(){
    Student stu = new Student(1,"zhangsan",20);
    MyClass myclass = new MyClass(stu,"and1510");
    JSONObject obj = new JSONObject(myclass);
    return obj.toString();
}

//4 {"list":[{"id":1,"age":20,"name":"张三"},
//{"id":2,"age":30,"name":"张三"}],"class_name":"and1510"}
public static String fun4(){
    Student stu1 = new Student(1,"zhangsan",20);
    Student stu2 = new Student(2,"lisi",21);
    List<Student> stulist = new ArrayList<Student>();
    stulist.add(stu1);
    stulist.add(stu2);
    MyClass2 myclass = new MyClass2("and1510", stulist);
    JSONObject obj1 = new JSONObject(myclass);
    return obj1.toString();
}


 /*[{"id":1,"age":20,"name":"张三"},{"id":2,"age":30,"name"
     * :"张三"}]*/
public static String fun5(){
    Student stu1 = new Student(1,"zhangsan",20);
    Student stu2 = new Student(2,"lisi",21);
    List<Student> stulist = new ArrayList<Student>();
    stulist.add(stu1);
    stulist.add(stu2);
    JSONArray array = new JSONArray(stulist);
    return array.toString();
    
}

/*{"myclass":{"list":[{"id":1,"age":20,"name":"张三"},{"id":2,"age":30,"name"
     * :"张三"}],"class_name":"and1510"}}*/
public static String fun6(){
    Student stu1 = new Student(1,"zhangsan",20);
    Student stu2 = new Student(2,"lisi",21);
    List<Student> stulist = new ArrayList<Student>();
    stulist.add(stu1);
    stulist.add(stu2);
    MyClass2 myclass = new MyClass2("and1510", stulist);
    JSONObject obj1 = new JSONObject(myclass);
    JSONObject obj2 = new JSONObject();
    try {
        obj2.put("myclss", obj1);
    } catch (JSONException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    return obj2.toString();
}

JSON解析

//{"student":{"id":1,"age":20,"name":"张三"}}
String json = JSONService.createJSON_02();
System.out.println(json);
Student stu = new Student();
JSONObject obj = new JSONObject(json);
//通过键student获得JSONObject对象
JSONObject obj2 = obj.getJSONObject("student");
//再从JSONObject对象中获得指定值所对应的值。并赋给Student
stu.setName(obj2.getString("name"));
stu.setAge(obj2.getInt("age"));
stu.setId(obj2.getInt("id"));
System.out.println(stu);