@Controller
@RequestMapping("/user")
public class UserControlelr {
    @PostMapping("/login")
    public String login(UserDTO userDTO){
        if (userDTO.getUsername() == null || userDTO.getUsername().isEmpty()){
            // 進(jìn)行某種操作
        }
        if(userDTO.getEmail() == null || userDTO.getEmail().isEmpty()){
            // 進(jìn)行某種操作
        }
        return "loginSuccess";
    }
}

@RestController
@Validated
public class Test1Controller {

    @PostMapping("/test1")
    public String test1(@NotEmpty String username, @Max(5) Integer value){
        return "校驗(yàn)普通參數(shù)";
    }

@Data
public class UserDTO {
    /**
     * 用戶名
     */
    @NotBlank
    private String username;

    /**
     * 密碼
     */
    @NotBlank
    private String pasword;

    /**
     * 郵箱
     */
    @Email
    private String email;
}

@RestController
public class Test2Controller {
    @PostMapping("/test2")
    public String test2(@Valid @RequestBody UserDTO userDTO){
        return "對象參數(shù)驗(yàn)證";
    }
}

@RestController
@Validated
public class Test3Controller {
    @PostMapping("/test3")
    public String test3(@Valid @RequestBody List<UserDTO> userDTOList){
        return "集合參數(shù)校驗(yàn)";
    }
}

@Data
public class UserListDTO {
    /**
     * List的name
     */
    @NotBlank
    private String listName;

    /**
     *  User列表
     */
    @Valid
    private List<UserDTO> userDTOList;
}

@RestController
public class Test4Controller {
    @PostMapping("/test4")
    public String test4(@Validated @RequestBody UserListDTO userListDTO){
        return "嵌套參數(shù)校驗(yàn)";
    }
}