JSON解析 Gson的使用

JSON解析 Gson的使用

• 数组

  • 数组转化为Json

    int[] numbers = {1, 1, 2, 3, 5, 8, 13};
    Gson gson = new Gson();
    String numbersJson = gson.toJson(numbers);      
    

  • json转化为数组

    int[] fibonacci = gson.fromJson(numbersJson, int[].class);
    for (int i = 0; i < fibonacci.length; i++) {
     System.out.print(fibonacci[i] + " ");
    }
    

• 集合

  • 集合转化为Json

    List names = new ArrayList();
    names.add("Alice");
    names.add("Bob");
    names.add("Carol");
    names.add("Mallory");
    Gson gson = new Gson();
    String jsonNames = gson.toJson(names);
    System.out.println("jsonNames = " + jsonNames);
    

  • json转化为集合

    Type type = new TypeToken>(){}.getType();
    List studentList = gson.fromJson(jsonStudents, type);
    
    for (Student student : studentList) {
        System.out.println("student.getName() = " + student.getName());
    }
    

• Map

  • Map转化为Json

    Map colours = new HashMap();
    colours.put("BLACK", "#000000");
    colours.put("RED", "#FF0000");
    colours.put("GREEN", "#008000");
    colours.put("BLUE", "#0000FF");
    colours.put("YELLOW", "#FFFF00");
    colours.put("WHITE", "#FFFFFF");
    Gson gson = new Gson();
    String json = gson.toJson(colours);
    System.out.println("json = " + json);
    

  • Json转化为Map

    Type type = new TypeToken>(){}.getType();
    Map map = gson.fromJson(json, type);
    for (String key : map.keySet()) {
        System.out.println("map.get = " + map.get(key));
    }
    

• JavaBean

  • Bean类转化为Json

    Calendar dob = Calendar.getInstance();
    dob.set(2000, 1, 1, 0, 0, 0);
    Student student = new Student("Duke", "Menlo Park", dob.getTime());
    Gson gson = new Gson();
    String json = gson.toJson(student);
    

  • Json转化为Bean

    String json = "{\"name\":\"Duke\",\"address\":\"Menlo Park\",\"dateOfBirth\":\"Feb 1, 2000 12:00:00 AM\"}";
    Gson gson = new Gson();
    Student student = gson.fromJson(json, Student.class);