使用Gson解析含有動態key的Json

使用Gson解析Json時，有時候會遇到key不是固定的情況，這個時候可以把它當做是一個Map。

{
    "students":{
        "101":{
            "name":"xiao hong",
             "age":10
        },
        "102":{
            "name":"xiao ming",
             "age":12
        },
        "103":{
            "name":"xiao qiang",
             "age":14
        }
    }
}

public class School {

    private Map<String,Student> students;

    public Map<String,Student> getStudents() {
        return students;
    }

    public void setStudents(Map<String,Student> students) {
        this.students = students;
    }

    public static class Student {

        private String name;
        private int age;

        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(String name, int age) {
            this.name = name;
            this.age = age;
        }
    }

    public School(Map<String, Student> students) {
        this.students = students;
    }
}

public class ExampleUnitTest {
    @Test
    public void testDeserializeSchool() {
        String data="{\n" +
                "    \"students\": {\n" +
                "        \"101\": {\n" +
                "            \"name\": \"xiao hong\",\n" +
                "            \"age\": 10\n" +
                "        },\n" +
                "        \"102\": {\n" +
                "            \"name\": \"xiao ming\",\n" +
                "            \"age\": 12\n" +
                "        },\n" +
                "        \"103\": {\n" +
                "            \"name\": \"xiao qiang\",\n" +
                "            \"age\": 14\n" +
                "        }\n" +
                "    }\n" +
                "}";
        Gson gson = new Gson();
        School school = gson.fromJson(data, School.class);
        Map<String,School.Student> students=school.getStudents();
        for (String key:students.keySet()){
            School.Student student=students.get(key);
            System.out.println("key:"+key+",name:"+student.getName()+",age:"+student.getAge());
        }
        //key:101,name:xiao hong,age:10
        //key:102,name:xiao ming,age:12
        //key:103,name:xiao qiang,age:14
    }

    @Test
    public void testSerializeSchool() {
        Gson gson = new Gson();
        Map<String,School.Student> students=new HashMap<>();
        students.put("104",new School.Student("xiong da",20));
        students.put("105",new School.Student("xiong er",19));
        students.put("106",new School.Student("xiong san",18));
        String data=gson.toJson(new School(students));
        System.out.println(data);
        //{"students":{"104":{"name":"xiong da","age":20},"105":{"name":"xiong er","age":19},"106":{"name":"xiong san","age":18}}}
    }
}