今天用Myeclipse添加Hibernate来操作mysql数据库
报了这个异常:
log4j:WARN No appenders could be found for logger (org.hibernate.cfg.Environment). log4j:WARN Please initialize the log4j system properly. Hibernate: insert into cztest.books (name, author) values (?, ?) Exception in thread "main" org.hibernate.exception.GenericJDBCException: could not insert: [com.cz.model.Books] at org.hibernate.exception.SQLStateConverter.handledNonSpecificException(SQLStateConverter.java:126) at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:114) 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 com.cz.test.UserTest.main(UserTest.java:30) Caused by: java.sql.SQLException: Field 'id' doesn't have a default value at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1055) at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:956) at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3491) at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3423) at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1936) at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2060) at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2542) at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1734) at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2019) at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:1937) at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:1922) at org.hibernate.id.IdentityGenerator$GetGeneratedKeysDelegate.executeAndExtract(IdentityGenerator.java:94) at org.hibernate.id.insert.AbstractReturningDelegate.performInsert(AbstractReturningDelegate.java:57) ... 16 more
解决办法:
将主键id设成:auto increment
详情见上传附件
注:
Books.hbm.xml:
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!--
Mapping file autogenerated by MyEclipse Persistence Tools
-->
<hibernate-mapping>
<class name="com.cz.model.Books" table="books" catalog="cztest">
<id name="id" type="java.lang.Integer">
<column name="id" />
<generator class="native " />
</id>
<property name="name" type="java.lang.String">
<column name="name" length="64" />
</property>
<property name="author" type="java.lang.String">
<column name="author" length="64" />
</property>
</class>
</hibernate-mapping>