如何在自定义注解的默认消息中获取字段名称？

huangapple
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英文:

How to get field Name in default message in custom annotation?

问题

我已创建自定义注解，用于在我的REST API项目的模型类属性中检查非空值。

  1. @Documented
  2. @Target({ ElementType.PARAMETER, ElementType.FIELD, ElementType.METHOD, ElementType.TYPE })
  3. @Retention(RetentionPolicy.RUNTIME)
  4. @ReportAsSingleViolation
  5. @Constraint(validatedBy = CheckNotNull.NotNullValidator.class)
  6. public @interface CheckNotNull {
  8.     String value() default "";
  10.     String message() default "{value} 不能为空";
  12.     Class<?>[] groups() default {};
  14.     Class<? extends Payload>[] payload() default {};
  16.     class NotNullValidator implements ConstraintValidator<CheckNotNull, String> {
  18.         @Override
  19.         public void initialize(CheckNotNull constraintAnnotation) {
  20.         }
  22.         @Override
  23.         public boolean isValid(String value, ConstraintValidatorContext context) {
  24.             return "null".equalsIgnoreCase(value) || value == null || value.trim().isEmpty();
  25.         }
  26.     }
  27. }

然而，如果我在属性上使用此注解。

  1. @CheckNotNull(value = "UserName")
  2. private String login;

我有另一个类捕获了 ConstraintViolationException。使用 @NotNull 注解时，它能够正常工作。

  1. public final class ValidationExceptionMapper implements ExceptionMapper<ValidationException> {
  3.     @Override
  4.     public Response toResponse(final ValidationException exception) {
  5.         RestError error = new RestError();
  7.         if (exception instanceof ConstraintViolationException) {
  8.             error.setHttpStatusCode(Response.Status.BAD_REQUEST.getStatusCode());
  9.             error.setCode(ErrorCodes.ERR_INVALID_INPUT);
  11.             final ConstraintViolationException cve = (ConstraintViolationException) exception;
  13.             StringBuilder msgBuilder = new StringBuilder("检测到以下约束违规：");
  14.             for(ConstraintViolation<?> violation: cve.getConstraintViolations()) {
  15.                 msgBuilder.append(StringEscapeUtils.escapeHtml(violation.getMessage()));
  16.             }
  17.             error.setMessage(msgBuilder.toString());
  18.         }
  19.         return Response.status(error.getHttpStatusCode())
  20.                 .entity(error)
  21.                 .type(MediaType.APPLICATION_JSON)
  22.                 .build();   
  23.     }
  24. }

但使用自定义注解时，我的逻辑无法正常工作。我的自定义注解是否存在问题？

欢迎提供任何意见。谢谢。

英文:

I have created custom annotation to check not null value for my model class attribute in my REST API project.

  1. @Documented
  2. @Target({ ElementType.PARAMETER, ElementType.FIELD, ElementType.METHOD, ElementType.TYPE })
  3. @Retention(RetentionPolicy.RUNTIME)
  4. @ReportAsSingleViolation
  5. @Constraint(validatedBy = CheckNotNull.NotNullValidator.class)
  6. public @interface CheckNotNull {
  8.     String value() default &quot;&quot;;
  10.     String message() default &quot;{value} can not be null or empty &quot;;
  12.     Class&lt;?&gt;[] groups() default {};
  14.     Class&lt;? extends Payload&gt;[] payload() default {};
  16.     class NotNullValidator implements ConstraintValidator&lt;CheckNotNull, String&gt; {
  18.         @Override
  19.         public void initialize(CheckNotNull constraintAnnotation) {
  20.         }
  22.         @Override
  23.         public boolean isValid(String value, ConstraintValidatorContext context) {
  24.             return &quot;null&quot;.equalsIgnoreCase(value) ? true : value == null ? true : value.trim().equals(&quot;&quot;) ? true :false;
  25.         }
  27.     }
  28. }

However, if I used this annotation on attribute.
ex:

  1. @CheckNotNull(value = &quot;UserName&quot;)
  2. private String login

I have another class where ConstraintViloationException is captured. With @NotNull annotation it is perfectly working.

  1. public final class ValidationExceptionMapper implements ExceptionMapper&lt;ValidationException&gt; {
  3.     @Override
  4.     public Response toResponse(final ValidationException exception) {
  5.         RestError error = new RestError();
  6.         
  7.         if (exception instanceof ConstraintViolationException) {
  8.             error.setHttpStatusCode(Response.Status.BAD_REQUEST.getStatusCode());
  9.             error.setCode(ErrorCodes.ERR_INVALID_INPUT);
  11.             final ConstraintViolationException cve = (ConstraintViolationException) exception;
  12.             
  13.             StringBuilder msgBuilder = new StringBuilder(&quot;Following constraint violations have been detected: &quot;);
  14.             for(ConstraintViolation&lt;?&gt; violation: cve.getConstraintViolations()) {
  15.                     msgBuilder.append(StringEscapeUtils.escapeHtml(violation.getMessage()));
  16.             }
  17.             error.setMessage(msgBuilder.toString());
  18.         }
  19.         return Response.status(error.getHttpStatusCode())
  20.                 .entity(error)
  21.                 .type(MediaType.APPLICATION_JSON)
  22.                 .build();   
  23.     }
  24. }

My logic is not working with applying custom annotation. Any issue with my custom annotation?

Any inputs are most welcome. Thank you.

答案1

得分: 1

你需要将该属性与您声明为任何动态消息的字段一起传递 {value} ；

在您的情况下，您需要将其传递如下： @CheckNotNull(value="name")。

  1. @CheckNotNull(value="name")
  2. private String firstName;
  4. @CheckNotNull(value="UserName")
  5. private String name;

这将对您有所帮助。

英文:

You need to pass that attribute with field whatever you had declared as any dynamic message {value} ;

In your case you need pass that as @CheckNotNull(value="name").

  1. @CheckNotNull(value=&quot;name&quot;)
  2. private String firstName;
  4. @CheckNotNull(value=&quot;UserName&quot;)
  5. private String name;

This will help you.

答案2

得分: 0

我已经覆盖了ValidationMessages.properties文件。

  1. javax.validation.constraints.NotNull.message = {0} 不能为空。
  2. org.hibernate.validator.constraints.NotBlank.message = {0} 不能为空
  3. org.hibernate.validator.constraints.NotEmpty.message = {0} 不能为空

然后，在我的响应类中：

  1. public Response toResponse(final ValidationException exception) {
  2.     RestError error = new RestError();
  3.     StringBuilder errorPath = new StringBuilder();
  4.     if (exception instanceof ConstraintViolationException) {
  5.         error.setHttpStatusCode(Response.Status.BAD_REQUEST.getStatusCode());
  7.         final ConstraintViolationException cve = (ConstraintViolationException) exception;
  9.         StringBuilder msgBuilder = new StringBuilder("以下约束违规已被检测到: ");
  10.         for (ConstraintViolation<?> violation : cve.getConstraintViolations()) {
  11.             Class<?> annotationType = violation.getConstraintDescriptor().getAnnotation().annotationType();
  13.             if (annotationType == NotEmpty.class || annotationType == NotNull.class
  14.                     || annotationType == NotBlank.class) {
  15.                 msgBuilder = getErrorMessage(violation, msgBuilder);
  16.             } else {
  17.                 msgBuilder.append(StringEscapeUtils.escapeHtml(violation.getMessage()));
  18.             }
  19.             errorPath.append(" 路径: ").append(violation.getPropertyPath().toString());
  20.         }
  21.         error.setMessage(msgBuilder.toString());
  22.     }
  23.     return Response.status(error.getHttpStatusCode())
  24.             .entity(error)
  25.             .type(MediaType.APPLICATION_JSON)
  26.             .build();
  27. }

我还为getErrorMessage编写了单独的方法：

  1. private StringBuilder getErrorMessage(ConstraintViolation<?> violation, StringBuilder msgBuilder) {
  2.     // 对于默认错误消息
  3.     if (violation.getMessage().contains("{0}")) {
  4.         String[] splitPath = violation.getPropertyPath().toString().split("[.]");
  5.         String fieldName = splitPath[splitPath.length - 1];
  6.         String messageWithFieldName = MessageFormat.format(violation.getMessage(), fieldName);
  7.         msgBuilder.append((messageWithFieldName)).append(";");
  8.     } else {
  9.         // 对于自定义错误消息
  10.         msgBuilder.append(violation.getMessage()).append(";");
  11.     }
  12.     return msgBuilder;
  13. }

因此，如果@NotNull、@NotEmpty和@NotBlank注解没有自定义消息，那么将默认消息中的占位符替换为从路径中提取的字段名，以便获得用户友好的错误消息。

示例：

  1. @NotNull
  2. private String name;
  4. 消息: "以下约束违规已被检测到: name 不能为空"
  6. @NotNull(message = "用户名不能为空")
  7. private String name;
  9. 消息: "以下约束违规已被检测到: 用户名不能为空"
  11. @NotNull
  12. @JsonProperty("username")
  13. private String name;
  15. 消息: "以下约束违规已被检测到: name 不能为空"
英文:

I have overridden ValidationMessages.properties file.

  1. javax.validation.constraints.NotNull.message  = {0} cannot be null or empty.
  2. org.hibernate.validator.constraints.NotBlank.message  = {0} cannot be null or empty
  3. org.hibernate.validator.constraints.NotEmpty.message  = {0} cannot be null or empty

And then, In my response class

  1. public Response toResponse(final ValidationException exception) {
  2.         RestError error = new RestError();
  3.         StringBuilder errorPath = new StringBuilder();
  4.         if (exception instanceof ConstraintViolationException) {
  5.             error.setHttpStatusCode(Response.Status.BAD_REQUEST.getStatusCode());
  7.             final ConstraintViolationException cve = (ConstraintViolationException) exception;
  8.             
  9.             StringBuilder msgBuilder = new StringBuilder(&quot;Following constraint violations have been detected: &quot;);
  10.             for(ConstraintViolation&lt;?&gt; violation: cve.getConstraintViolations()) {
  11.                 Class&lt;?&gt; annotationType = violation.getConstraintDescriptor().getAnnotation().annotationType();
  13.                if (annotationType == NotEmpty.class || annotationType == NotNull.class
  14.                         || annotationType == NotBlank.class) {
  15.                     msgBuilder = getErrorMessage(violation, msgBuilder);
  16.                 }
  17.                 else {
  18.                     msgBuilder.append(StringEscapeUtils.escapeHtml(violation.getMessage()));
  19.                 }
  20.                 errorPath.append(&quot; path: &quot;).append(violation.getPropertyPath().toString());
  21.                 
  22.                
  23.             }
  24.             error.setMessage(msgBuilder.toString());
  25.         } 
  26.         return Response.status(error.getHttpStatusCode())
  27.                 .entity(error)
  28.                 .type(MediaType.APPLICATION_JSON)
  29.                 .build();   
  30.     }

And I have written separate method for getErrorMessage

  1. private StringBuilder getErrorMessage(ConstraintViolation&lt;?&gt; violation, StringBuilder msgBuilder) {
  2.         // For default error message
  3.         if (violation.getMessage().contains(&quot;{0}&quot;)) {
  4.             String[] splitPath =  violation.getPropertyPath().toString().split(&quot;[.]&quot;);
  5.             String fieldName = splitPath[splitPath.length - 1];
  6.             String messageWithFieldName = MessageFormat.format(violation.getMessage(), fieldName);
  7.             msgBuilder.append((messageWithFieldName)).append(&quot;;&quot;);
  8.         } else {
  9.             // For customized error message
  10.             msgBuilder.append(violation.getMessage()).append(&quot;;&quot;);
  11.         }
  12.         return msgBuilder;
  13.     }

so if their is no custom message for @NotNull, @NotEmpty and @NotBlank annotation, then replace placeholder in default message with field name which is extracted from the path in order to have user-friendly error message.
examples:

  1. @NotNull
  2. private String name;
  4. message: &quot;Following constraint violations have been detected: name cannot be null or empty&quot;
  7. @NotNull(message = &quot;UserName can not be null&quot;)
  8. private String name;
  10. message: &quot;Following constraint violations have been detected: UserName can not be null&quot;
  13. @NotNull
  14. @JsonProperty(&quot;username&quot;)
  15. private String name;
  17. message: &quot;Following constraint violations have been detected: name cannot be null or empty&quot;

huangapple
  • 本文由 发表于 2020年8月27日 04:23:15
  • 转载请务必保留本文链接：https://go.coder-hub.com/63605225.html
  • annotations
  • jackson
  • java
  • rest
  • validation
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