Contents

1. 1. Spring如何对Enum进行validate
   1. 1.1. 前言
   2. 1.2. 示例代码

Spring如何对Enum进行validate

前言

Spring的HTTP请求中，一般都需要对接口参数进行校验，如：在对象上使用@NotNull等注解；
那么如何对枚举(enum)进行校验呢？

1. 新建一个自定义注解@ValueOfEnum：

   @Documented
   @Constraint(validatedBy = ValueOfEnumValidator.class)
   @Target({ElementType.METHOD, ElementType.FIELD, ElementType.PARAMETER})
   @Retention(RetentionPolicy.RUNTIME)
   public @interface ValueOfEnum {
   
       String message() default "value must be one of {values}";
   
       Class<?>[] groups() default {};
   
       Class<? extends Payload>[] payload() default {};
   
       Class<? extends Enum<?>> enumClass();
   
       int[] excluded() default {};
   }
   

2. 新建一个自定义校验器：

   public class ValueOfEnumValidator implements ConstraintValidator<ValueOfEnum, Integer> {
       private Enum<?>[] enumConstants;
   
       private int[] excluded;
   
       @Override
       public void initialize(ValueOfEnum constraintAnnotation) {
           enumConstants = constraintAnnotation.enumClass().getEnumConstants();
           excluded = constraintAnnotation.excluded();
       }
   
       @Override
       public boolean isValid(Integer value, ConstraintValidatorContext context) {
           if (value == null) {
               return true;
           }
           if (Arrays.stream(excluded).anyMatch(excluded -> Objects.equals(value, excluded))) {
               return false;
           }
           return Arrays.stream(enumConstants).anyMatch(e -> {
               if (e instanceof EnumWithCode) {
                   return Objects.equals(((EnumWithCode) e).getCode(), value);
               } else {
                   return e.ordinal() == value;
               }
           });
       }
   }
   

3. 使用该自定义注解：

   @Data
   public class FooCmd implements Serializable {
   
       @NotNull(message = "enum type must not be empty")
       @ValueOfEnum(enumClass = FooEnum.class, excluded = {100}, message = "enum type must be 200 or 300")
       private Integer value;
   }
   

示例代码

完整示例代码：Enum validator