SpringBoot之参数校验

Java SpringBoot 参数校验

一、SpringBoot之参数校验

1、SpringBoot提供的参数校验注解

除了@NotEmpty和@NotBlank将 null 值认为是非法的之外，其它注解如@Size, @Max, @Min等都将 null 认为是有效的，如果不允许 null 值，则需要额外添加@NotNull注解。

@Data
public class Employee implements Serializable {
  private static final long serialVersionUID = -8224860450904540019L;
  @NotEmpty(message = "名字不能为空")
  @UTF8Size(max = 16, message = "name should be short than 128")
  private String name;
  @Email
  private String email;
  @NotBlank(message = "city is required")
  @Size(max = 128, message = "city should be short than 128")
  private String city;
  @CreditCardNumber(message = "invalid credit card number")
  private String ccNumber;
  @Pattern(regexp = "^(0[1-9]|1[0-2])([\\\\/])([1-9][0-9])$", message = "required format MM/YY")
  private String ccExpiration;
  @Digits(integer = 3, fraction = 0, message = "invalid CVV")
  private String ccCVV;
}

2、自定义校验注解

@Size并不能支持中文字符，可以自定义如下然后在需要校验字符（中英文）的字段上使用@UTF8Size即可。

@Documented
@Constraint(validatedBy = Utf8SizeValidator.class)
@Target({METHOD, FIELD})
@Retention(RetentionPolicy.RUNTIME)
public @interface UTF8Size {
  String message() default "{javax.validation.constraints.Size.message}";
  int min() default 0;
  int max() default Integer.MAX_VALUE;
  Class<?>[] groups() default {};
  Class<? extends Payload>[] payload() default {};
}

public class Utf8SizeValidator implements ConstraintValidator<UTF8Size, String> {
  private int maxCharSize;
  @Override
  public void initialize(UTF8Size constraintAnnotation) {
    this.maxCharSize = constraintAnnotation.max();
  }
  @Override
  public boolean isValid(String value, ConstraintValidatorContext context) {
    if (Objects.isNull(value)) {
      return true;
    }
    return value.getBytes(Charset.forName("GB18030")).length <= maxCharSize;
  }
}

二、字段校验的使用

使用 Bean Validation API 的@Valid注解，或者 Spring Context 提供的@Validated注解启用对 Bean 的校验。主要区别是，@Validated是@Valid的变体，支持分组校验（validation groups）。

A.这种写法会将异常信息抛给全局异常处理

@PostMapping("/emp")
public String addEmploy(@RequestBody  @Valid Employee employee) {
  log.info("employee to create: {}", employee);
  String employeeId = UUID.randomUUID().toString();
  return employeeId;
}

B.如果需要捕获参数校验的异常结果，写法如下

:::danger 这种写法不会将异常处理的结果返回给全局异常处理 :::

@PostMapping()
UserInfo addUser(@RequestBody @Valid UserInfo userInfo, BindingResult bindingResult) {
    userService.addUser(userInfo);
    return userInfo;
}

三、字段校验的全局异常处理

package org.hand.train.springboot.springboot.exception;
import lombok.extern.slf4j.Slf4j;
import org.springframework.http.HttpStatus;
import org.springframework.validation.BindingResult;
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 org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.ResponseStatus;
import java.util.stream.Collectors;
/**
 * GlobalExceptionHandler
 * encoding:UTF-8
 *
 * @author Fcant
 * @date 10:02 2019/12/4
 */
@Slf4j
@ControllerAdvice
public class GlobalExceptionHandler {
    @ExceptionHandler(MethodArgumentNotValidException.class)
    @ResponseBody
    @ResponseStatus(HttpStatus.BAD_REQUEST)
    public String handleMethodArgumentNotValidException(
            MethodArgumentNotValidException exception) {
        log.error("method argument not valid: {}", exception.getMessage());
        String errorMessage = "field error";
        BindingResult bindingResult = exception.getBindingResult();
        if (bindingResult.hasErrors()) {
            errorMessage = bindingResult.getFieldErrors().stream()
                    .map(FieldError::getDefaultMessage)
                    .collect(Collectors.joining(" | "));
        }
        return errorMessage;
    }
}

四、分组校验

相同字段在不同场景需要不同的验证策略

A.组接口

public class GroupVaildDTO {
    public interface SaveGroup extends Default {}
    public interface UpdateGroup extends Default {}
}

B.校验的JavaBean属性

public class GroupsValidForm {
    @Null(message = "id必须为null", groups = {GroupVaildDTO.SaveGroup.class})
    @NotNull(message = "id不能为null", groups = {GroupVaildDTO.UpdateGroup.class})
    private Integer id;
    @NotBlank(message = "用户名不能为空")
    private String userName;
    @Override
    public String toString() {
        final StringBuffer sb = new StringBuffer("GroupsValidForm{");
        sb.append("id=").append(id);
        sb.append(", userName='").append(userName).append('\'');
        sb.append('}');
        return sb.toString();
    }
}

C.Controller层分组校验的使用

相同字段在不同场景需要不同的验证策略

@PostMapping(value = "update")
    public ServerResponse update(@RequestBody @Validated(value = GroupVaildDTO.UpdateGroup.class)
                                            GroupsValidForm groupsValidForm, BindingResult results) {
    if (results.hasErrors()) {
        return ServerResponse.createByErrorMessage(results.getFieldError().getDefaultMessage());
    }
    return ServerResponse.createBySuccess();
}