This example scenario: using the postman tool to access http://localhost The corresponding background method of 8080/user/insert is the following code

@RestController
@RequestMapping("/user")
public class UserController {

    @Autowired
    private UserMapper userMapper;
    
    @PostMapping("/insert")
    public int insert(@RequestBody User user) {
        return userMapper.insert(user);
    }
}

Parsing: when you add @ requestbody to the background method parameters, you need JSON (application/JSON) format to encapsulate the request parameters into user objects. Solution: you can access it normally by setting the following in postman, which is convenient for debugging.