不跳过春季批处理中的异常

Question

Spring 批处理无法跳过以下异常。任何人都可以建议我在这里错过了什么吗？

<batch:job id="runPromotion">   
        <batch:step id="readPromotionStep">
            <batch:tasklet ref="processPromotion"></batch:tasklet>
            <batch:next on="SUCCESS" to="getPromotionalPoints" />
            <batch:end on="FAILED"></batch:end> 
            <batch:listeners>
                <batch:listener ref="queryProvider"/>           
            </batch:listeners>          
        </batch:step>
        <batch:step id="getPromotionalPoints">      
            <batch:tasklet >            
                <batch:chunk reader="transactionDataReader" writer="userPromotionWriter" commit-interval="100" skip-limit="100">                
                <batch:skippable-exception-classes >
                    <batch:include class="org.hibernate.exception.ConstraintViolationException"/>
                    <batch:include class="javax.persistence.PersistenceException"/>
                </batch:skippable-exception-classes>
                </batch:chunk>
            </batch:tasklet>
            <batch:listeners>
                <batch:listener ref="queryProvider"/>           
            </batch:listeners>


        </batch:step>   

    </batch:job>

下面是运行批处理时出错：

2013-08-24 14:43:16,451 - [main] 警告：org.hibernate.engine.jdbc.spi.SqlExceptionHelper：143 - SQL 错误：1062，SQLState：23000 2013-08-24 14:43:16,451 - [main] 错误：org.hibernate.engine.jdbc.spi.SqlExceptionHelper:144 - 键 'promotion_id' 的重复条目 '1' javax.persistence.PersistenceException：org.hibernate.exception.ConstraintViolationException：键“promotion_id”的重复条目“1” 在 org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1377)

Answer 1

如果你看错误

javax.persistence.PersistenceException: org.hibernate.exception.ConstraintViolationException

您会注意到 PersistenceException 是引发的实际错误，而 ConstraintViolationException 是原因。这就是为什么将 ConstraintViolationException 添加到 skippable-exception-classes 不起作用的原因，但我很惊讶即使 PersistenceException 对您也不起作用。它对我有用（但我顺便使用了 Java 配置）。此外，由于您还将 PersistenceException（它是 ConstraintViolationException 的超类）添加到 skippable-exception-classes，因此添加 ConstraintViolationException 似乎是多余的。

我假设您只想跳过 ConstraintViolationException。我尝试了两种解决方案（但使用 Java 配置）：

1. 实施 SkipPolicy 以创建自定义船长。注意我们如何检查抛出异常的原因是否是ConstraintViolationException：

   package pkg;
   
   import javax.persistence.PersistenceException;
   import org.hibernate.exception.ConstraintViolationException;
   import org.springframework.batch.core.step.skip.SkipLimitExceededException;
   import org.springframework.batch.core.step.skip.SkipPolicy;
   import org.springframework.stereotype.Component;
   
   public class ConstraintViolationExceptionSkipper implements SkipPolicy {
   
       private int skipLimit;
   
       @Override
       public boolean shouldSkip(Throwable t, int skipCount) throws SkipLimitExceededException {
         if(t instanceof PersistenceException && 
             t.getCause() instanceof ConstraintViolationException) {
           return true;
         }
         return false;
       }
   
       public void setSkipLimit(int skipLimit) {
         this.skipLimit = skipLimit;
       }
   }
   

   并将上述跳过者设置为块中的 skip-policy 并摆脱 skippable-exception-classes 块。还要注意这里是如何设置 skip-limit 的：

   <batch:chunk reader="transactionDataReader" writer="userPromotionWriter" commit-interval="100" 
       skip-policy="skipPolicy" />
   
   <bean id="skipPolicy" class=pkg.ConstraintViolationExceptionSkipper">
     <property name="skipLimit" value="100" />
   </bean>
   

2. 修改您的编写器以捕获 PersistenceException 并将其作为 ConstraintVioaltionException 重新抛出。我不确定您是如何实现 userPromotionWriter 的，但下面是一个示例实现。它使用 JPA 进行持久化，显式刷新 EntityManager 并捕获并抛出一个新异常，就像我刚才所说的：

   package pkg;
   
   import java.util.List;
   
   import javax.persistence.EntityManager;
   import javax.persistence.PersistenceContext;
   
   import org.hibernate.exception.ConstraintViolationException;
   import org.springframework.batch.item.ItemWriter;
   import org.springframework.stereotype.Component;
   
   @Component("userPromotionWriter")
   public class UserPromotionWriter implements ItemWriter<User> {
   
     @PersistenceContext
     private EntityManager entityManger;
   
     @Override
     public void write(List<? extends User> users) throws Exception {
         for(User user : users) {
           entityManger.persist(user);
           try {
               entityManger.flush();
           } catch(Exception e) {
               if(e.getCause() instanceof ConstraintViolationException) {
                   throw new ConstraintViolationException("Tried to insert a User record with a non-unique user_id of " + user.getUserId(), null, null);
               }
               throw e;
           }
           finally {
             entityManger.clear();
           }
         }
      }
   }
   

   现在，由于抛出的异常是 ConstraintViolationException（而不是 PersistenceException），因此以下内容可以正常工作：

   <batch:chunk reader="transactionDataReader" writer="userPromotionWriter" commit-interval="100" skip-limit="100"> <batch:skippable-exception-classes > <batch:include class="org.hibernate.exception.ConstraintViolationException"/> </batch:skippable-exception-classes> </batch:chunk>