1.4.1 对象与JSON转化 1.4.2 JSON与List集合转化 1.1.1 获取json中的属性 day10-05

1.1.1 对象与JSON转化

@Test

public void toJSON() throws IOException{

Jedis jedis = new Jedis("192.168.126.174",6379);

User user = new User();

user.setId(100);

user.setName("json测试");

user.setAge(100);

user.setSex("男");

ObjectMapper objectMapper =

new ObjectMapper();

String userJSON =

objectMapper.writeValueAsString(user);

System.out.println(userJSON);

//将用户信息保存到redis中

jedis.set("user", userJSON);

String user_json = jedis.get("user");

//将json串转化为对象

User user2 =

objectMapper.readValue(user_json,User.class);

System.out.println(user2);

}

1.1.2 JSON与List集合转化

//将List集合转化json

@Test

public void listToJSON() throws IOException{

List<User> userList = new ArrayList<>();

for(int i=0;i<4;i++){

User user = new User();

user.setId(i);

user.setName("变形金刚"+i);

user.setAge(10+i);

user.setSex("男");

userList.add(user);

}

ObjectMapper objectMapper = new ObjectMapper();

String userListJSON =

objectMapper.writeValueAsString(userList);

System.out.println(userListJSON);

//将listJSON转化为集合

User[] users =

objectMapper.readValue(userListJSON, User[].class);

/*List<User> u_list =

objectMapper.readValue(userListJSON,userList.getClass());*/

System.out.println(Arrays.asList(users));

}

1.1.1 获取json中的属性

@Test

public void getJSON() throws IOException{

List<User> userList = new ArrayList<>();

for(int i=0;i<4;i++){

User user = new User();

user.setId(i);

user.setName("变形金刚"+i);

user.setAge(10+i);

user.setSex("男");

userList.add(user);

}

ObjectMapper objectMapper = new ObjectMapper();

String userListJSON =

objectMapper.writeValueAsString(userList);

System.out.println(userListJSON);

//读取json  获取json中下标为2的元素

JsonNode jsonNode =

objectMapper.readTree(userListJSON).get(2);

System.out.println(jsonNode);

//获取json属性值

String name = jsonNode.get("name").asText();

System.out.println("获取json串中的值:"+name);

}