HibernateValidator自定義驗證

前言

在本身的摸索下對HibernateValidator有了初步的認識，能夠使用已有的約束條件對字段作出限制，減小不要代碼的出現，使代碼更簡潔。
但在最近的實際使用中，出現了一些沒法使用框架處理的問題，例如，在第三方請求個人接口時，根據status字段區分不一樣的業務邏輯；status=1進行A邏輯處理，status=2進行B邏輯處理；在網絡了檢索了相關信息後，作出以下總結。

步驟

1. 使用通用Mapper插件生成實體類和mapper,這裏爲了聚焦對HibernateValidator的使用，把關注點放在實體類Brand中,在實體類中，對status字段添加自定義約束@StatusConstraint

   package com.codeup.mybatisjoin.model;
   
   import com.codeup.mybatisjoin.validation.StatusConstraint;
   import lombok.Data;
   import javax.persistence.Column;
   import javax.persistence.Id;
   import javax.validation.constraints.NotBlank;
   import javax.validation.constraints.NotNull;
   
   @Data
   public class Brand {
      
       @Id
       @Column(name = "brand_ID")
       private Long brandId;
   
   
       /**
        * 使用`@NotNull`添加約束
        */
       @Column(name = "vendor_ID")
       @NotNull(message = "[vendorId]不可爲空")
       private Long vendorId;
   
   
       /**
        * 使用`@NotBlank`添加約束
        */
       @Column(name = "brand_name")
       @NotBlank(message = "[brandName]字段不可爲空")
       private String brandName;
   
       private String description;
   
   
       /**
        * 自定義約束
        */
       @StatusConstraint(message = "[status]爲1或者2")
       private String status;
   }

2. @StatusConstraint實現步驟和自定義註解類似

   package com.codeup.mybatisjoin.validation;
   
   import javax.validation.Constraint;
   import javax.validation.Payload;
   import java.lang.annotation.ElementType;
   import java.lang.annotation.Retention;
   import java.lang.annotation.RetentionPolicy;
   import java.lang.annotation.Target;
   
   /**
    * @ProjectName: mybatisjoin
    * @Package: com.codeup.mybatisjoin.validation
    * @ClassName: StatusConstraint
    * @Author: lhc
    * @Description: 狀態約束
    * @Date: 2019/8/22 下午 3:36
    */
   @Target({ElementType.FIELD, ElementType.METHOD})
   @Retention(RetentionPolicy.RUNTIME)
   /**
    * 指出當前約束是經過`StatusConstraintValidator.class`來實現的
    */
   @Constraint(validatedBy = StatusConstraintValidator.class)
   public @interface StatusConstraint {
   
       /**
        * 配置message信息
        * @return
        */
       String message() default "違規參數";
   
       /**
        * 分組
        * @return
        */
       Class<?>[] groups() default {};
   
       Class<? extends Payload>[] payload() default {};
   }

3. 經過查看源代碼裏面的文檔得知要要實現ConstraintValidator接口

   @Documented
   @Target({ ANNOTATION_TYPE })
   @Retention(RUNTIME)
   public @interface Constraint {
   
       /**
        * {@link ConstraintValidator} classes implementing the constraint. The given 
   classes
        * must reference distinct target types for a given {@link ValidationTarget}. 
   If two
        * {@code ConstraintValidator}s refer to the same type, an exception will 
   occur.
        * <p>
        * At most one {@code ConstraintValidator} targeting the array of parameters of
        * methods or constructors (aka cross-parameter) is accepted. If two or more
        * are present, an exception will occur.
        *
        * @return array of {@code ConstraintValidator} classes implementing the 
   constraint
        */
       Class<? extends ConstraintValidator<?, ?>>[] validatedBy();
   }

4. 實現ConstraintValidator接口，重寫isValid()方法，實現本身的判斷邏輯

   package com.codeup.mybatisjoin.validation;
   
   import lombok.extern.slf4j.Slf4j;
   
   import javax.validation.ConstraintValidator;
   import javax.validation.ConstraintValidatorContext;
   
   /**
    * @ProjectName: mybatisjoin
    * @Package: com.codeup.mybatisjoin.validation
    * @ClassName: StatusConstraintValidator
    * @Author: lhc
    * @Description: TODO
    * @Date: 2019/8/22 下午 3:38
    */
   @Slf4j
   public class StatusConstraintValidator implements 
   ConstraintValidator<StatusConstraint,Object> {
   
       @Override
       public boolean isValid(Object value, ConstraintValidatorContext context) {
           String statCode = (String) value;
           // 等於1或2返回true,反之
           if ("1".equals(statCode) || "2".equals(statCode)) {
               return true;
           }
           return false;
       }
   }

5. 至此，對字段添加約束條件已完成。還存在一個重要的操做是對約束的校驗，這裏經過工具類實現

   package com.codeup.mybatisjoin.validation;
   
   import org.hibernate.validator.HibernateValidator;
   
   import javax.validation.ConstraintViolation;
   import javax.validation.Validation;
   import javax.validation.Validator;
   import java.util.Set;
   
   /**
    * @ProjectName: mybatisjoin
    * @Package: com.codeup.mybatisjoin.validation
    * @ClassName: ValidatorConfig
    * @Author: lhc
    * @Description: TODO
    * @Date: 2019/8/22 下午 4:31
    */
   public class ValidatorUtil {
   
   
       /**
        * 配置hibernate_validator和快速失敗模式
        */
       private static Validator validator = 
   Validation.byProvider(HibernateValidator.class)
              .configure()
              .failFast(true)
              .buildValidatorFactory()
              .getValidator();
   
   
       /**
        * 參數校驗，若未匹配約束，則經過已將將以前定義的`message`拋出
        * @param object 參數
        * @param groups 屬於組
        */
       public static void result(Object object, Class<?>... groups) {
           Set<ConstraintViolation<Object>> constraintViolations = 
   validator.validate(object, groups);
            if (constraintViolations.size() > 0) {
               String message = constraintViolations.iterator().next().getMessage();
               throw new MissingParameterException(message);
           }
       }
   }

6. 將message信息拋出以後，須要以更統一的方式返回給第三方，使用統一異常處理機制解決

   • 自定義異常類MissingParameterException

     package com.codeup.mybatisjoin.validation;
     
     public class MissingParameterException extends RuntimeException {
     
         public MissingParameterException(String message) {
             super(message);
         }
     }

   • 統一異常處理

     package com.codeup.mybatisjoin.validation;
     
     import org.springframework.web.bind.annotation.ExceptionHandler;
     import org.springframework.web.bind.annotation.RestControllerAdvice;
     
     import java.util.HashMap;
     import java.util.Map;
     
     
     @RestControllerAdvice
     public class GlobalExceptionHandler {
     
         @ExceptionHandler(MissingParameterException.class)
         public Map<String, Object> invalidParameter(MissingParameterException e) {
             Map<String, Object> map = new HashMap<>();
             map.put("code", 500);
             map.put("message", e.getMessage());
             return map;
         }
     }

• 經過請求查看返回結果

  package com.codeup.mybatisjoin.controller;
  
  import com.codeup.mybatisjoin.model.Brand;
  import com.codeup.mybatisjoin.validation.ValidatorUtil;
  import lombok.extern.slf4j.Slf4j;
  import org.springframework.web.bind.annotation.PostMapping;
  import org.springframework.web.bind.annotation.RequestBody;
  import org.springframework.web.bind.annotation.RequestMapping;
  import org.springframework.web.bind.annotation.RestController;
  
  import java.util.LinkedHashMap;
  import java.util.Map;
  
  
  @Slf4j
  @RestController
  @RequestMapping(value = "/brandConroller")
  public class BrandConroller {
  
      @PostMapping(value = "/go")
      public Map<String, Object> go(@RequestBody Brand brand) {
          ValidatorUtil.result(brand);
          Map<String, Object> map = new LinkedHashMap<>();
          log.info("brand:{}", brand);
          return map;
      }
  }

1. 請求

   // request
    {
       "brandId": 1,
       "vendorId": 1,
       "brandName": "demoData",
       "description": "demoData",
          "status": "3"
   }
   // response
   {
       "code": 500,
       "message": "[status]爲1或者2"
   }

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