org.hibernate.AssertionFailure: Interceptor.onPrepareStatement() returned null

映射文件配置正确,但报如下的异常:

org.hibernate.AssertionFailure: Interceptor.onPrepareStatement() returned null or empty string.
at org.hibernate.jdbc.AbstractBatcher.getSQL(AbstractBatcher.java:453)
at org.hibernate.jdbc.AbstractBatcher.getPreparedStatement(AbstractBatcher.java:473)
at org.hibernate.jdbc.AbstractBatcher.prepareSelectStatement(AbstractBatcher.java:123)
at org.hibernate.id.IncrementGenerator.getNext(IncrementGenerator.java:83)
at org.hibernate.id.IncrementGenerator.generate(IncrementGenerator.java:44)
at org.hibernate.event.def.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:98)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:186)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:175)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.performSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:98)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:70)
at org.hibernate.impl.SessionImpl.fireSaveOrUpdate(SessionImpl.java:509)
at org.hibernate.impl.SessionImpl.saveOrUpdate(SessionImpl.java:501)
at org.hibernate.impl.SessionImpl.saveOrUpdate(SessionImpl.java:497)
at com.test.testCategory.saveOrUpdate(testCategory.java:157)
at com.test.testCategory.test(testCategory.java:115)
at com.test.testCategory.main(testCategory.java:233)

我的原因是:创建session 的时候加入了拦截器Interceptor， 但在拦截器的实现类内的public String onPrepareStatement(String sql)方法返回了一个null值,所以出现了上面的异常. 

 

public class ForumInterceptor implements Interceptor, Serializable{

....................
....................
@Override
public String onPrepareStatement(String arg0) {
// TODO Auto-generated method stub
       return null;
}

.....................
}

在创建session之前使用了interceptor拦截器,但ForumInterceptor的onPrepareStatement(String arg0)方法
返回null值:
ForumInterceptor forumInterceptor = new ForumInterceptor();
session = getSessionFactory(configFile).openSession(forumInterceptor);	
forumInterceptor.setSession(session);	
Object[] arr = new Object[2];	
arr = new Object[2];
arr[0] = configFile;
arr[1] = session;
sessionStack.push(arr);

 

 我将onPrepareStatement(String arg0) 方法的返回值改为arg0后,再次执行代码就没有出现该异常了. 

public class ForumInterceptor implements Interceptor, Serializable{

....................
....................
@Override
public String onPrepareStatement(String arg0) {
// TODO Auto-generated method stub
       return arg0;
}

.....................
}