Bean Validation怎么用？

本文目录导读：

1. Bean Validation 使用指南
2. 添加依赖
3. 常用注解
4. 验证分组
5. 使用方式
6. 自定义验证
7. 全局异常处理
8. 常用验证注解总结

Bean Validation 使用指南

Bean Validation（JSR 380）是Java中用于验证Java Bean的标准规范，最常用的实现是Hibernate Validator。

添加依赖

Maven

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

或单独使用

<dependency>
    <groupId>org.hibernate.validator</groupId>
    <artifactId>hibernate-validator</artifactId>
    <version>6.2.0.Final</version>
</dependency>
<dependency>
    <groupId>javax.validation</groupId>
    <artifactId>validation-api</artifactId>
    <version>2.0.1.Final</version>
</dependency>

常用注解

实体类验证注解

public class User {
    @NotNull(message = "ID不能为空")
    private Long id;
    @NotBlank(message = "用户名不能为空")
    @Size(min = 2, max = 20, message = "用户名长度需要在2-20之间")
    private String username;
    @Email(message = "邮箱格式不正确")
    private String email;
    @Pattern(regexp = "^1[3-9]\\d{9}$", message = "手机号格式不正确")
    private String phone;
    @Min(value = 18, message = "年龄不能小于18岁")
    @Max(value = 60, message = "年龄不能大于60岁")
    private Integer age;
    @Past(message = "生日必须是过去的时间")
    private Date birthday;
    @Future(message = "过期时间必须是未来的时间")
    private Date expireDate;
    @Positive(message = "价格必须为正数")
    private BigDecimal price;
    @NotBlank(message = "状态不能为空")
    @Pattern(regexp = "ACTIVE|INACTIVE", message = "状态只能为ACTIVE或INACTIVE")
    private String status;
    // getters and setters
}

验证分组

// 定义分组接口
public interface CreateGroup {}
public interface UpdateGroup {}
// 使用分组
public class User {
    @NotNull(groups = UpdateGroup.class, message = "更新时ID不能为空")
    private Long id;
    @NotBlank(groups = {CreateGroup.class, UpdateGroup.class}, 
              message = "用户名不能为空")
    private String username;
    @Email(groups = CreateGroup.class, message = "邮箱格式不正确")
    private String email;
}

使用方式

方式1：手动验证

ValidatorFactory factory = Validation.buildDefaultValidatorFactory();
Validator validator = factory.getValidator();
User user = new User();
// 设置属性...
// 验证所有规则
Set<ConstraintViolation<User>> violations = validator.validate(user);
// 按组验证
Set<ConstraintViolation<User>> violations2 = validator.validate(user, CreateGroup.class);
// 处理验证结果
for (ConstraintViolation<User> violation : violations) {
    System.out.println(violation.getMessage());
    System.out.println(violation.getPropertyPath());
    System.out.println(violation.getInvalidValue());
}

方式2：Spring Boot Controller验证

@RestController
public class UserController {
    @PostMapping("/users")
    public ResponseEntity<?> createUser(
            @Valid @RequestBody User user,
            BindingResult result) {
        if (result.hasErrors()) {
            Map<String, String> errors = new HashMap<>();
            result.getFieldErrors().forEach(error -> 
                errors.put(error.getField(), error.getDefaultMessage()));
            return ResponseEntity.badRequest().body(errors);
        }
        // 处理业务逻辑
        return ResponseEntity.ok("创建成功");
    }
    // 简化方式：使用@Validated
    @PostMapping("/users/v2")
    public ResponseEntity<?> createUserV2(
            @Validated(CreateGroup.class) @RequestBody User user) {
        // 验证失败会自动抛出异常
        return ResponseEntity.ok("创建成功");
    }
}

方式3：@Validated注解

@Service
@Validated
public class UserService {
    public User createUser(@Valid User user) {
        // 验证失败会抛出 ConstraintViolationException
        return userRepository.save(user);
    }
}

自定义验证

创建自定义注解

@Target({ElementType.FIELD, ElementType.PARAMETER})
@Retention(RetentionPolicy.RUNTIME)
@Constraint(validatedBy = {PhoneValidator.class})
public @interface Phone {
    String message() default "手机号格式不正确";
    Class<?>[] groups() default {};
    Class<? extends Payload>[] payload() default {};
}

实现验证器

public class PhoneValidator implements ConstraintValidator<Phone, String> {
    private static final String PHONE_REGEX = "^1[3-9]\\d{9}$";
    @Override
    public boolean isValid(String value, ConstraintValidatorContext context) {
        if (value == null) {
            return true; // 非空验证由@NotNull处理
        }
        return value.matches(PHONE_REGEX);
    }
}

使用自定义注解

public class User {
    @Phone(message = "手机号格式错误")
    private String phone;
}

全局异常处理

@RestControllerAdvice
public class GlobalExceptionHandler {
    @ExceptionHandler(MethodArgumentNotValidException.class)
    public ResponseEntity<?> 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 ResponseEntity.badRequest().body(errors);
    }
    @ExceptionHandler(ConstraintViolationException.class)
    public ResponseEntity<?> handleConstraintViolation(
            ConstraintViolationException ex) {
        Map<String, String> errors = new HashMap<>();
        ex.getConstraintViolations().forEach(violation -> {
            String fieldName = violation.getPropertyPath().toString();
            String errorMessage = violation.getMessage();
            errors.put(fieldName, errorMessage);
        });
        return ResponseEntity.badRequest().body(errors);
    }
}

常用验证注解总结

这样，你就可以在Java应用中使用Bean Validation进行数据验证了。