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

import jakarta.validation.constraints.*;
public class User {
    @NotNull(message = "用戶名不能為空")
    @Size(min = 2, max = 10, message = "用戶名長度必須在2到10之間")
    private String username;
    @NotNull(message = "密碼不能為空")
    @NotBlank(message = "密碼不能為空")
    @Pattern(regexp = "^(?=.*\\d)(?=.*[A-Za-z])(?=.*[@$!%*#?&])[A-Za-z\\d@$!%*#?&]{8,20}$", message = "密碼格式不正確")
    private String password;
    @Email(message = "郵箱格式不正確")
    private String email;
    @Min(value = 18, message = "年齡必須大于等于18歲")
    private Integer age;
    public User() {}
    // Getters and Setters
}

import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RestController;
import jakarta.validation.Valid;
import jakarta.validation.constraints.NotNull;
@RestController
public class UserController {
    @PostMapping("/register")
    public ResponseEntity<?> register(@Valid @RequestBody User user) {
        // 業(yè)務邏輯
        return ResponseEntity.ok("注冊成功");
    }
}

import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.validation.FieldError;
import org.springframework.web.bind.MethodArgumentNotValidException;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import jakarta.validation.ConstraintViolation;
import jakarta.validation.ConstraintViolationException;
import java.util.HashMap;
import java.util.Map;
@ControllerAdvice
public class GlobalExceptionHandler {
    @ExceptionHandler(MethodArgumentNotValidException.class)
    public ResponseEntity<Map<String, String>> handleValidationExceptions(MethodArgumentNotValidException ex) {
        Map<String, String> errors = new HashMap<>();
        ex.getBindingResult().getAllErrors().forEach((error) -> {
            String fieldName = ((FieldError) error).getField();
            String errorMessage = error.getDefaultMessage();
            errors.put(fieldName, errorMessage);
        });
        return new ResponseEntity<>(errors, HttpStatus.BAD_REQUEST);
    }
}

import jakarta.validation.Constraint;
import jakarta.validation.Payload;
import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
@Documented
@Constraint(validatedBy = {PhoneValidator.class})
@Target({ElementType.FIELD})
@Retention(RetentionPolicy.RUNTIME)
public @interface Phone {
    String message() default "手機號格式不正確";
    Class<?>[] groups() default {};
    Class<? extends Payload>[] payload() default {};
}

import jakarta.validation.ConstraintValidator;
import jakarta.validation.ConstraintValidatorContext;
public class PhoneValidator implements ConstraintValidator<Phone, String> {
    @Override
    public void initialize(Phone constraintAnnotation) {
    }
    @Override
    public boolean isValid(String value, ConstraintValidatorContext context) {
        if (value == null) {
            return false;
        }
        // 手機號正則表達式
        String regex = "^1(3\\d|5[i-o]\\d|78\\d|4\\d)\\d{7}$";
        return value.matches(regex);
    }
}

@Phone(message = "手機號格式不正確")
private String phone;

public interface SaveGroup {
}
public interface UpdateGroup {
}
@NotNull(groups = SaveGroup.class)
@Size(min = 2, max = 10, groups = {SaveGroup.class, UpdateGroup.class})
private String username;

@PostMapping("/save")
public ResponseEntity<?> save(@Validated(SaveGroup.class) @RequestBody User user) {
    // 業(yè)務邏輯
    return ResponseEntity.ok("保存成功");
}

@ScriptAssert(lang = "javascript", script = "password.length >= 8 && password.match(/^(?=.*\\d)(?=.*[A-Za-z])(?=.*[@$!%*#?&])[A-Za-z\\d@$!%*#?&]{8,20}$/)")
public class User {
    // 字段定義
}

@Aspect
@Component
public class ValidationAspect {
    @Around("execution(* *(..)) && @annotation(org.springframework.web.bind.annotation.PostMapping)")
    public Object logAround(ProceedingJoinPoint joinPoint) throws Throwable {
        try {
            Object[] args = joinPoint.getArgs();
            if (args != null && args.length > 0) {
                for (Object arg : args) {
                    if (arg != null && arg.getClass().getAnnotation(Valid.class) != null) {
                        // 記錄日志
                        System.out.println("開始校驗數(shù)據(jù)：" + arg);
                    }
                }
            }
            return joinPoint.proceed();
        } catch (MethodArgumentNotValidException ex) {
            // 記錄校驗失敗的日志
            System.out.println("校驗失敗：" + ex.getBindingResult());
            throw ex;
        }
    }
}