JSON解析器的Jackson_java对象转json_List&Map和JSON解析器的Jackson_json转Java对象

JSON解析器的Jackson_java对象转json_List&Map

复杂java对象转换

1.list：数组

    @Test
    public void test3() throws Exception {
        //创建Person对象
        Person p = new Person();
        p.setName("张三");
        p.setAge(23);
        p.setGender("男");
        p.setBirthday(new Date());


        Person p1 = new Person();
        p1.setName("张三");
        p1.setAge(23);
        p1.setGender("男");
        p1.setBirthday(new Date());

        Person p2 = new Person();
        p2.setName("张三");
        p2.setAge(23);
        p2.setGender("男");
        p2.setBirthday(new Date());

        //创建一个List集合
        List<Person> ps = new ArrayList<>();
        ps.add(p);
        ps.add(p1);
        ps.add(p2);

        //创建Jackson的核心对象 ObjectMapper
        ObjectMapper mapper = new ObjectMapper();
        String json = mapper.writeValueAsString(ps);
        System.out.println(json);
    }

2.Map：对象格式一致

    @Test
    public void test4() throws Exception {
        //创建map对象
        HashMap<String, Object> map = new HashMap<String, Object>();
        map.put("name","李四");
        map.put("age","26");
        map.put("gender","男");
        //创建Jackson的核心对象 ObjectMapper
        ObjectMapper mapper = new ObjectMapper();
        String json = mapper.writeValueAsString(map);
        System.out.println(json);
    }

JSON解析器的Jackson_json转Java对象

1.导入Jackson的相关jar包

2.创建Jackson核心对象 ObjectMapper

3.调用objectMapper的相关方法进行转换

　　readValue(json字符串数据,Class)

    @Test
    public void test5() throws Exception {
        //初始化JSON字符串
        String json = "{\"gender\":\"男\",\"name\":\"李四\",\"age\":\"26\"}";
        //创建ObjectMapper对象
        ObjectMapper mapper = new ObjectMapper();
        Person person = mapper.readValue(json, Person.class);
        System.out.println(person);
    }

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