public class UserController {
    public ResponseEntity<String> registerUser(String username, String password) {
        if (username == null || username.isEmpty()) {
            return ResponseEntity.badRequest().body("用戶名不能為空");
        }
        if (password == null || password.isEmpty()) {
            return ResponseEntity.badRequest().body("密碼不能為空");
        }
        if (password.length() < 6) {
            return ResponseEntity.badRequest().body("密碼長(zhǎng)度至少為6位");
        }
        // 處理用戶注冊(cè)邏輯
        return ResponseEntity.ok("用戶注冊(cè)成功");
    }
}

<dependency>
    <groupId>org.hibernate.validator</groupId>
    <artifactId>hibernate-validator</artifactId>
    <version>6.2.0.Final</version>
</dependency>

public class User {
    @NotBlank(message = "用戶名不能為空")
    private String username;
    @Min(value = 18, message = "年齡不能小于18歲")
    private int age;
    // 構(gòu)造函數(shù)、Getter 和 Setter 方法
}

public class ValidatorTest {
    public static void main(String[] args) {
        // 創(chuàng)建校驗(yàn)器
        ValidatorFactory factory = Validation.buildDefaultValidatorFactory();
        Validator validator = factory.getValidator();
        // 創(chuàng)建用戶對(duì)象
        User user = new User();
        user.setUsername("");
        user.setAge(16);
        // 執(zhí)行校驗(yàn)
        Set<ConstraintViolation<User>> violations = validator.validate(user);
        // 處理校驗(yàn)結(jié)果
        if (!violations.isEmpty()) {
            for (ConstraintViolation<User> violation : violations) {
                System.out.println(violation.getMessage());
            }
        } else {
            System.out.println("校驗(yàn)通過(guò)");
        }
    }
}

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-validation</artifactId>
</dependency>

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>

@Configuration
@EnableAutoConfiguration
public class HibernateValidatorConfiguration {
	@Bean
	public MethodValidationPostProcessor methodValidationPostProcessor() {
		MethodValidationPostProcessor processor = new MethodValidationPostProcessor();
		processor.setValidator(validator());
		processor.setProxyTargetClass(true);
		return processor;
	}
	@Bean
	public Validator validator() {
		return Validation
				.byProvider(HibernateValidator.class)
				.configure()
				.addProperty("hibernate.validator.fail_fast", "true")
				.buildValidatorFactory()
				.getValidator();
	}
}

@ControllerAdvice
@Slf4j
public class GlobalExceptionHandler {
    @ExceptionHandler(value = ConstraintViolationException.class)
	@ResponseBody
	public ApiResult defaultInsuranceExceptionHandler(ConstraintViolationException e) {
		log.error("校驗(yàn)錯(cuò)誤:{}", e.getMessage());
		return ApiResult.error("error", e.getMessage());
	}
	@ExceptionHandler(value = MissingServletRequestParameterException.class)
	@ResponseBody
	public ApiResult handleMissingServletRequestParameter(MissingServletRequestParameterException ex) {
		String error = ex.getParameterName() + " 參數(shù)為空";
		return ApiResult.error("error", error);
	}
}

@Data
public class UserRegistrationRequest {
    @NotBlank(message = "用戶名不能為空")
    private String username;
    @NotBlank(message = "密碼不能為空")
    @Size(min = 6, message = "密碼長(zhǎng)度至少為6位")
    private String password;
}

@RestController
public class UserController {
    @PostMapping("/register")
    public ResponseEntity<String> registerUser(@Valid @RequestBody UserRegistrationRequest request) {
        // 處理用戶注冊(cè)邏輯
        return ResponseEntity.ok("用戶注冊(cè)成功");
    }
}

processor.setProxyTargetClass(true);

@RestController
public class ValidController implements ValidClient {
	@Override
	public String queryById(Integer id) {
		return "id:" + id;
	}
}

public interface UpdateGroup {
}

public class UserRegistrationRequest {
    @NotBlank(message = "用戶名不能為空", groups = {RegistrationGroup.class})
    private String username;
    @NotBlank(message = "密碼不能為空")
    @Size(min = 6, message = "密碼長(zhǎng)度至少為6位")
    private String password;
    // 其他字段和方法
}

@RestController
public class UserController {
    @PostMapping("/register")
    public ResponseEntity<String> registerUser(@Validated(RegistrationGroup.class) @RequestBody UserRegistrationRequest request) {
        // 處理用戶注冊(cè)邏輯
        return ResponseEntity.ok("用戶注冊(cè)成功");
    }
    @PostMapping("/update")
    public ResponseEntity<String> updateUser(@Validated(UpdateGroup.class) @RequestBody UserRegistrationRequest request) {
        // 處理用戶更新邏輯
        return ResponseEntity.ok("用戶更新成功");
    }
}

@Documented
@Constraint(validatedBy = DateFormatValidator.class)
@Target({ElementType.METHOD, ElementType.FIELD, ElementType.ANNOTATION_TYPE, ElementType.CONSTRUCTOR, ElementType.PARAMETER, ElementType.TYPE_USE})
@Retention(RetentionPolicy.RUNTIME)
public @interface DateFormat {
	//默認(rèn)錯(cuò)誤消息
	String message() default "時(shí)間格式錯(cuò)誤";
	//分組
	Class<?>[] groups() default {};
	//默認(rèn)日期格式
	String formatter() default "yyyy-MM-dd";
	//負(fù)載
	Class<? extends Payload>[] payload() default {};
	@Target({ElementType.METHOD, ElementType.FIELD, ElementType.ANNOTATION_TYPE, ElementType.CONSTRUCTOR, ElementType.PARAMETER, ElementType.TYPE_USE})
	@Retention(RetentionPolicy.RUNTIME)
	@Documented
	@interface List {
		DateFormat[] value();
	}
}

public class DateFormatValidator implements ConstraintValidator<DateFormat, String> {
	protected String dateFormatter;
	@Override
	public void initialize(DateFormat constraintAnnotation) {
		this.dateFormatter = constraintAnnotation.formatter();
	}
	@Override
	public boolean isValid(String value, ConstraintValidatorContext constraintValidatorContext) {
		if (StringUtils.isNotBlank(value)) {
			try {
				DateUtils.parseDate(value, dateFormatter);
			} catch (Exception e) {
				return false;
			}
			return true;
		}
		return false;
	}
}

public class RequestParam {
    @DateFormat(message = "日期輸入錯(cuò)誤")
    private String beginDate;
    // 其他字段和方法
}