使用Hibernate做个简单的测试插入数据不能成功

Question

log4j:WARN No appenders could be found for logger (org.hibernate.cfg.Environment).
log4j:WARN Please initialize the log4j system properly.
Hibernate: insert into tbl_user (uname, upass) values (?, ?)
Exception in thread "main" org.hibernate.exception.ConstraintViolationException: could not insert: [entity.User]
at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:94)
at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66)
at org.hibernate.id.insert.AbstractReturningDelegate.performInsert(AbstractReturningDelegate.java:64)
at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2176)
at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2656)
at org.hibernate.action.EntityIdentityInsertAction.execute(EntityIdentityInsertAction.java:71)
at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:279)
at org.hibernate.event.def.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:321)
at org.hibernate.event.def.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:204)
at org.hibernate.event.def.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:130)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:210)
at org.hibernate.event.def.DefaultSaveEventListener.saveWithGeneratedOrRequestedId(DefaultSaveEventListener.java:56)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:195)
at org.hibernate.event.def.DefaultSaveEventListener.performSaveOrUpdate(DefaultSaveEventListener.java:50)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:93)
at org.hibernate.impl.SessionImpl.fireSave(SessionImpl.java:563)
at org.hibernate.impl.SessionImpl.save(SessionImpl.java:551)
at org.hibernate.impl.SessionImpl.save(SessionImpl.java:547)
at dao.UserDaoTest.testSave(UserDaoTest.java:49)
at dao.UserDaoTest.main(UserDaoTest.java:24)
Caused by: com.microsoft.sqlserver.jdbc.SQLServerException: 不能将值 NULL 插入列 'uid'，表 'neusoftbookdb.dbo.tbl_user'；列不允许有空值。INSERT 失败。
at com.microsoft.sqlserver.jdbc.SQLServerException.makeFromDatabaseError(Unknown Source)
at com.microsoft.sqlserver.jdbc.IOBuffer.processPackets(Unknown Source)
at com.microsoft.sqlserver.jdbc.SQLServerStatement.sendExecute(Unknown Source)
at com.microsoft.sqlserver.jdbc.SQLServerStatement.doExecuteUpdate(Unknown Source)
at com.microsoft.sqlserver.jdbc.SQLServerPreparedStatement.executeUpdate(Unknown Source)
at org.hibernate.id.IdentityGenerator$GetGeneratedKeysDelegate.executeAndExtract(IdentityGenerator.java:94)
at org.hibernate.id.insert.AbstractReturningDelegate.performInsert(AbstractReturningDelegate.java:57)
... 17 more
有高手能告诉我怎么回事吗？我刚刚学的框架照着视频上打的！但是确出现这个问题！查询更改和删除都行！就是插入数据不行

Answer 1

这不是很明显，你的uid字段不能为空

Answer 2

有赋值啊！我用了User u=new User(4,"张三","abc");
     
        Transaction tx =session.beginTransaction();
        tx.begin();
       session.save(u);
       tx.commit();
       赋值的了！但是依然说uid为空啊

Answer 3

有赋值啊！我用了User u=new User(4,"张三","abc");
     
        Transaction tx =session.beginTransaction();
        tx.begin();
       session.save(u);
       tx.commit();
       赋值的了！但是依然说uid为空啊

Answer 4

insert into tbl_user (uname, upass) values (?, ?)
很显然，你的SQL语句中没有uid...

Answer 5

你这里的uid是主键，你应该在xml文件中设置主键类型的时候设置错了，把你现在uid的主键类型发来看一下

Answer 6

你的hibernate配置文件配置错了，主键类型如果是uuid的话，hibnernate自动生成uuid32位主键，如果是assined类型的话，需要你给主键值赋值。<generator class="uuid.hex"/>；<generator class="assigned"/>

Answer 7

你的uid应该是主键吧 不能为空。

Answer 8

你把User类和对应的hbm发出来看看