jackson的使用

@Test
public void test2(){
    ObjectMapper objectMapper = new ObjectMapper();
    People peo = new People(2,"zhangsan");
    try {
        //1.jackson对对象的操作
        //吧数据转换成字符串
        String s = objectMapper.writeValueAsString(peo);
        System.out.println(s);
        //把字符串转换成对象
        People peo1 = objectMapper.readValue(s, People.class);
        System.out.println(peo1);
        List<People> list1 = new ArrayList<People>();
        list1.add(peo);
        //2.jackson对list的操作
        System.out.println("----------------------");
        //把List转换成的字符串
        String s1 = objectMapper.writeValueAsString(list1);
        System.out.println(s1);
        //把字符串转换成List
        List<People> result1 = objectMapper.readValue(s1, new TypeReference<List<People>>() {});
        System.out.println(result1);
        //3.jackson对map的操作
        System.out.println("----------------------");
        Map<String,People> map = new HashMap<String, People>();
        map.put("peo",peo);
        String s2 = objectMapper.writeValueAsString(map);
        System.out.println(s2);
        Map<String,People> result = objectMapper.readValue(s2, new TypeReference<Map<String,People>>() {});
        System.out.println(result.get("peo"));
    } catch (JsonProcessingException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
}