Spring jackson Spring jackson原理及基本使用方法详解

<!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-databind -->
  <dependency>
   <groupId>com.fasterxml.jackson.core</groupId>
   <artifactId>jackson-databind</artifactId>
   <version>2.11.2</version>
  </dependency>

@Test
public void test01() throws JsonProcessingException {
  //创建User对象
  User user=new User("admin","1111");
  //将user转为json格式
  ObjectMapper objectMapper=new ObjectMapper();
  String userString=objectMapper.writeValueAsString(user);
  System.out.println(userString);
}

 @Test
public void test02() throws JsonProcessingException {
  //创建json对象
  String json="{\"username\":\"admin\",\"password\":\"1111\"}";
  //将json对象转为java对象
  ObjectMapper objectMapper=new ObjectMapper();
  User user=objectMapper.readValue(json,User.class);
  System.out.println(user);
}

@Test
public void test03() throws JsonProcessingException {
  //创建User对象
  User user=new User("admin","1111");
  //存储User对象
  List<User> userList=new ArrayList<User>();
  userList.add(user);
  userList.add(user);
  userList.add(user);
  //集合转json
  ObjectMapper objectMapper=new ObjectMapper();
  String listJson=objectMapper.writeValueAsString(userList);
  System.out.println(listJson);
}