Hibernate中的一对一关系
2009-09-18 14:47
169 查看
首先转别人的一片例子：
转贴：http://www.wangchao.net.cn/bbsdetail_68735.html
-----------------------------------------------------------------------------------------------------------------------------------------------
一对一关联有两种映射方式：一种是使用主键关联，限制两个数据表的主键使用相同的值；另一种是一个外键和一个惟一关键字对应。
下面的例子采用主键关联。一人一个房间。
SQL:
CREATE TABLE user (
USER_ID varchar(10) NOT NULL default '',
NAME varchar(16) NOT NULL default '',
PRIMARY KEY (USER_ID)
);
CREATE TABLE room (
ROOM_ID varchar(10) NOT NULL default '',
ADDRESS varchar(32) NOT NULL default '',
PRIMARY KEY (ROOM_ID)
);
User.java:
package ivan.hibernate.one2one;
public class User {
private long id;
private String name;
private Room room;
...//Getters and Setters
}
User.hbm.xml:
<hibernate-mapping>
<class name="ivan.hibernate.one2one.User" table="USER">
<id name="id" column="USER_ID" unsaved-value="0">
<generator class="increment"/>
</id>
<property name="name">
<column name="NAME" length="16" not-null="true"/>
</property>
<one-to-one name="room"
class="ivan.hibernate.one2one.Room"
cascade="all"/>
</class>
</hibernate-mapping>
Room.java:
package ivan.hibernate.one2one;
public class Room {
private long id;
private String address;
private User user;
...// Getters and Setters
}
Room.hbm.xml:
<hibernate-mapping>
<class name="ivan.hibernate.one2one.Room" table="ROOM">
<id name="id" column="ROOM_ID" unsaved-value="0">
<generator class="foreign">
<param name="property">user</param>
</generator>
</id>
<property name="address" type="string"/>
<one-to-one name="user"
class="ivan.hibernate.one2one.User"
constrained="true"/>
</class>
</hibernate-mapping>
hibernate.cfg.xml:
<hibernate-configuration>
<session-factory>
<!-- properties -->
<property name="connection.username">root</property>
<property name="connection.url">jdbc:mysql://localhost:3306/hibernate</property>
<property name="dialect">net.sf.hibernate.dialect.MySQLDialect</property>
<property name="connection.password"></property>
<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
<mapping resource="ivan/hibernate/one2one/Room.hbm.xml" />
<mapping resource="ivan/hibernate/one2one/User.hbm.xml" />
</session-factory>
</hibernate-configuration>
Test.java:
package ivan.hibernate.one2one;
import net.sf.hibernate.*;
import net.sf.hibernate.cfg.*;
public class Test {
public static void main(String[] args) throws HibernateException {
SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();
Room room = new Room();
room.setAddress("China-10-911");
User user = new User();
user.setName("bush");
user.setRoom(room);
room.setUser(user);
Session session = sessionFactory.openSession();
Transaction tx= session.beginTransaction();
session.save(user);
tx.commit();
session.close();
sessionFactory.close();
}
}
运行后，在mysql，hibernate 数据库中可看见 User 表和 Room 表都增加了一条记录。
存在问题：如果 Room 表已经存在某个 id 值的记录，而增加的 User 记录的 id 将会是此 id 值，将会抛出异常：java.sql.BatchUpdateException: Duplicate entry ...。这是因为 Room 的 id 是根据 User 的 id 来的。如果新增加的 id 在 Room 表中已经存在，就会抛出 SQL 异常。您可以试验，上面步骤成功后，只将表 User 清空。这样表 User 的记录 id 自增又会从 1 开始。当重新运行程序时就会抛出异常。
-----------------------------------------------------------------------------------------------------------------------------------------------
这篇文章是从网上搜索到的，原因是自己的工程当时遇见一个问题，我这边的机器人服务器的Hibernate和另外一边的PHP公用一个数据库的两张表：
uchome_blog：
blogid mediumint(8) unsigned not null
uid mediumint(8) unsigned not null
username char(15) not null
....
uchome_blogfield
blogid mediumint(8) unsigned not null
uid mediumint(8) unsigned not null
message mediumtext not null
.....
现在的情况是：上面两张表关系是一对一，其中，blogfield的主键参照blog的主键，字段名字和值都是相同的，操作中保持级联更新删除。
数据库是MySQL5，配置文件<因为我负责机器人部分去了，我整完框架，这部分就有另外一个同事去做了，配置文件是他写的>：
<class name="UchomeBlog" table="uchome_blog" catalog="stage_uhome">
<id name="blogid" type="java.lang.Integer">
<column name="blogid" />
<generator class="increment" />
</id>
<property name="uid" type="java.lang.Integer">
<column name="uid" not-null="true" />
</property>
<property name="username" type="java.lang.String">
<column name="username" length="15" not-null="true" />
</property>
<property name="subject" type="java.lang.String">
<column name="subject" length="80" not-null="true" />
</property>
<property name="classid" type="java.lang.Short">
<column name="classid" not-null="true" />
</property>
<property name="viewnum" type="java.lang.Integer">
<column name="viewnum" not-null="true" />
</property>
<property name="replynum" type="java.lang.Integer">
<column name="replynum" not-null="true" />
</property>
<property name="tracenum" type="java.lang.Integer">
<column name="tracenum" not-null="true" />
</property>
<property name="dateline" type="long">
<column name="dateline" not-null="true" />
</property>
<property name="pic" type="java.lang.String">
<column name="pic" length="120" not-null="true" />
</property>
<property name="picflag" type="java.lang.Byte">
<column name="picflag" not-null="true" />
</property>
<property name="noreply" type="java.lang.Byte">
<column name="noreply" not-null="true" />
</property>
<property name="friend" type="java.lang.Byte">
<column name="friend" not-null="true" />
</property>
<property name="password" type="java.lang.String">
<column name="password" length="10" not-null="true" />
</property>
<one-to-one name="blogfield"
class="UchomeBlogfield"
cascade="all"/>
</class>
<class name="UchomeBlogfield" table="uchome_blogfield" catalog="stage_uhome">
<id name="blogid" column="blogid" unsaved-value="0">
<generator class="foreign">
<param name="property">blog</param>
</generator>
</id>
<property name="uid" type="java.lang.Integer">
<column name="uid" not-null="true" />
</property>
<property name="tag" type="java.lang.String">
<column name="tag" not-null="true" />
</property>
<property name="message" type="java.lang.String">
<column name="message" length="16777215" not-null="true" />
</property>
<property name="postip" type="java.lang.String">
<column name="postip" length="20" not-null="true" />
</property>
<property name="related" type="java.lang.String">
<column name="related" length="65535" not-null="true" />
</property>
<property name="relatedtime" type="long">
<column name="relatedtime" not-null="true" />
</property>
<property name="targetIds" type="java.lang.String">
<column name="target_ids" length="65535" not-null="true" />
</property>
<one-to-one name="blog"
class="UchomeBlog"
constrained="true"/>
</class>
工程能跑起来，开始操作也正常，保存了几次之后，抛出异常：
2009-09-18 10:13:53,312 - 3056875 [pool-1-thread-1] WARN org.hibernate.util.JDBCExceptionReporter - SQL Error: 1062, SQLState: 23000
2009-09-18 10:13:53,312 - 3056875 [pool-1-thread-1] ERROR org.hibernate.util.JDBCExceptionReporter - Duplicate entry '6659' for key 'PRIMARY'
2009-09-18 10:13:53,328 - 3056891 [pool-1-thread-1] ERROR org.hibernate.event.def.AbstractFlushingEventListener - Could not synchronize database state with session
org.hibernate.exception.ConstraintViolationException: Could not execute JDBC batch update
at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:71)
at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:249)
at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:235)
at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:139)
at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:298)
at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:27)
at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1000)
at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:338)
at org.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:106)
at org.springframework.orm.hibernate3.HibernateTransactionManager.doCommit(HibernateTransactionManager.java:575)
at org.springframework.transaction.support.AbstractPlatformTransactionManager.processCommit(AbstractPlatformTransactionManager.java:651)
at org.springframework.transaction.support.AbstractPlatformTransactionManager.commit(AbstractPlatformTransactionManager.java:621)
at org.springframework.transaction.interceptor.TransactionAspectSupport.commitTransactionAfterReturning(TransactionAspectSupport.java:311)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:117)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:161)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:203)
at $Proxy5.publishBlog(Unknown Source)
at sun.reflect.GeneratedMethodAccessor65.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:304)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:172)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:139)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:107)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:161)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:203)
at $Proxy6.publishBlog(Unknown Source)
at sun.reflect.GeneratedMethodAccessor65.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:304)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:172)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:139)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:107)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:161)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:203)
at $Proxy6.publishBlog(Unknown Source)
at com.iouyou.robot.model.helper.MessageProcesser.processMsg(MessageProcesser.java:156)
at com.iouyou.robot.model.QQRobotModel.handleCommonsMessage(QQRobotModel.java:238)
at com.iouyou.robot.model.QQRobotModel.receivedCommonsMessage(QQRobotModel.java:198)
at com.iouyou.robot.model.QQRobotModel.qqEvent(QQRobotModel.java:129)
at edu.tsinghua.lumaqq.qq.QQClient.fireQQEvent(QQClient.java:1084)
at edu.tsinghua.lumaqq.qq.BasicFamilyProcessor.processReceiveIM(BasicFamilyProcessor.java:1836)
at edu.tsinghua.lumaqq.qq.BasicFamilyProcessor.packetArrived(BasicFamilyProcessor.java:275)
at edu.tsinghua.lumaqq.qq.ProcessorRouter.packetArrived(ProcessorRouter.java:64)
at edu.tsinghua.lumaqq.qq.QQClient.firePacketArrivedEvent(QQClient.java:1073)
at edu.tsinghua.lumaqq.qq.PacketEventTrigger.call(PacketEventTrigger.java:47)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
at java.util.concurrent.FutureTask.run(FutureTask.java:138)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:98)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:207)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:619)
Caused by: java.sql.BatchUpdateException: Duplicate entry '6659' for key 'PRIMARY'
at com.mysql.jdbc.PreparedStatement.executeBatchSerially(PreparedStatement.java:1669)
at com.mysql.jdbc.PreparedStatement.executeBatch(PreparedStatement.java:1085)
at sun.reflect.GeneratedMethodAccessor64.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.logicalcobwebs.proxool.ProxyStatement.invoke(ProxyStatement.java:100)
at org.logicalcobwebs.proxool.ProxyStatement.intercept(ProxyStatement.java:57)
at $java.sql.Statement$$EnhancerByProxool$$7b04b7fe.executeBatch(<generated>)
at org.hibernate.jdbc.BatchingBatcher.doExecuteBatch(BatchingBatcher.java:48)
at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:242)
... 52 more
Hibernate 我一般只是当作框架来用，很少深入框架本身里面一些东西，这个错误以前没遇见过。说是主键重复，可是到数据库查那个重复的主键，查不到数据，感觉有点奇怪，而且服务器跑起来之后，是保存了几条记录之后才出现这个问题的。
搜索了一下，于是搜索到上面转贴的帖子，大概理解了一下。于是尝试把映射文件的generator改称为native（在我用Hibernate和MySQL的经历中，从来都是用native的）映射文件如下：
<class name="UchomeBlog" table="uchome_blog" catalog="stage_uhome">
<id name="blogid" type="java.lang.Integer">
<column name="blogid" />
<generator class="native" />
</id>
<property name="uid" type="java.lang.Integer">
<column name="uid" not-null="true" />
</property>
<property name="username" type="java.lang.String">
<column name="username" length="15" not-null="true" />
</property>
<property name="subject" type="java.lang.String">
<column name="subject" length="80" not-null="true" />
</property>
<property name="classid" type="java.lang.Short">
<column name="classid" not-null="true" />
</property>
<property name="viewnum" type="java.lang.Integer">
<column name="viewnum" not-null="true" />
</property>
<property name="replynum" type="java.lang.Integer">
<column name="replynum" not-null="true" />
</property>
<property name="tracenum" type="java.lang.Integer">
<column name="tracenum" not-null="true" />
</property>
<property name="dateline" type="long">
<column name="dateline" not-null="true" />
</property>
<property name="pic" type="java.lang.String">
<column name="pic" length="120" not-null="true" />
</property>
<property name="picflag" type="java.lang.Byte">
<column name="picflag" not-null="true" />
</property>
<property name="noreply" type="java.lang.Byte">
<column name="noreply" not-null="true" />
</property>
<property name="friend" type="java.lang.Byte">
<column name="friend" not-null="true" />
</property>
<property name="password" type="java.lang.String">
<column name="password" length="10" not-null="true" />
</property>
<one-to-one name="blogfield"
class="UchomeBlogfield"
cascade="all"/>
</class>
<class name="UchomeBlogfield" table="uchome_blogfield" catalog="stage_uhome">
<id name="blogid" column="blogid" unsaved-value="0">
<generator class="foreign">
<param name="property">blog</param>
</generator>
</id>
<property name="uid" type="java.lang.Integer">
<column name="uid" not-null="true" />
</property>
<property name="tag" type="java.lang.String">
<column name="tag" not-null="true" />
</property>
<property name="message" type="java.lang.String">
<column name="message" length="16777215" not-null="true" />
</property>
<property name="postip" type="java.lang.String">
<column name="postip" length="20" not-null="true" />
</property>
<property name="related" type="java.lang.String">
<column name="related" length="65535" not-null="true" />
</property>
<property name="relatedtime" type="long">
<column name="relatedtime" not-null="true" />
</property>
<property name="targetIds" type="java.lang.String">
<column name="target_ids" length="65535" not-null="true" />
</property>
<one-to-one name="blog"
class="UchomeBlog"
constrained="true"/>
</class>
跑一下，OK。于是不停的测试，不停的发保存记录。跑到了现在几个小时过去，还是没问题。看来问题是在这里了。
但是具体的详细问题出现的原因在哪里，还不知道。现在列出hibernate3中关于主键映射到底是native还是increment的描述：
increment：用于为long, short或者int类型生成 唯一标识。只有在没有其他进程往同一张表中插入数据时才能使用。 在集群下不要使用。
native：根据底层数据库的能力选择identity, sequence 或者hilo中的一个。
关于increment的试用，Hibernate API里面说的如此清楚了，呵呵。
转贴：http://www.wangchao.net.cn/bbsdetail_68735.html
-----------------------------------------------------------------------------------------------------------------------------------------------
一对一关联有两种映射方式：一种是使用主键关联，限制两个数据表的主键使用相同的值；另一种是一个外键和一个惟一关键字对应。
下面的例子采用主键关联。一人一个房间。
SQL:
CREATE TABLE user (
USER_ID varchar(10) NOT NULL default '',
NAME varchar(16) NOT NULL default '',
PRIMARY KEY (USER_ID)
);
CREATE TABLE room (
ROOM_ID varchar(10) NOT NULL default '',
ADDRESS varchar(32) NOT NULL default '',
PRIMARY KEY (ROOM_ID)
);
User.java:
package ivan.hibernate.one2one;
public class User {
private long id;
private String name;
private Room room;
...//Getters and Setters
}
User.hbm.xml:
<hibernate-mapping>
<class name="ivan.hibernate.one2one.User" table="USER">
<id name="id" column="USER_ID" unsaved-value="0">
<generator class="increment"/>
</id>
<property name="name">
<column name="NAME" length="16" not-null="true"/>
</property>
<one-to-one name="room"
class="ivan.hibernate.one2one.Room"
cascade="all"/>
</class>
</hibernate-mapping>
Room.java:
package ivan.hibernate.one2one;
public class Room {
private long id;
private String address;
private User user;
...// Getters and Setters
}
Room.hbm.xml:
<hibernate-mapping>
<class name="ivan.hibernate.one2one.Room" table="ROOM">
<id name="id" column="ROOM_ID" unsaved-value="0">
<generator class="foreign">
<param name="property">user</param>
</generator>
</id>
<property name="address" type="string"/>
<one-to-one name="user"
class="ivan.hibernate.one2one.User"
constrained="true"/>
</class>
</hibernate-mapping>
hibernate.cfg.xml:
<hibernate-configuration>
<session-factory>
<!-- properties -->
<property name="connection.username">root</property>
<property name="connection.url">jdbc:mysql://localhost:3306/hibernate</property>
<property name="dialect">net.sf.hibernate.dialect.MySQLDialect</property>
<property name="connection.password"></property>
<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
<mapping resource="ivan/hibernate/one2one/Room.hbm.xml" />
<mapping resource="ivan/hibernate/one2one/User.hbm.xml" />
</session-factory>
</hibernate-configuration>
Test.java:
package ivan.hibernate.one2one;
import net.sf.hibernate.*;
import net.sf.hibernate.cfg.*;
public class Test {
public static void main(String[] args) throws HibernateException {
SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();
Room room = new Room();
room.setAddress("China-10-911");
User user = new User();
user.setName("bush");
user.setRoom(room);
room.setUser(user);
Session session = sessionFactory.openSession();
Transaction tx= session.beginTransaction();
session.save(user);
tx.commit();
session.close();
sessionFactory.close();
}
}
运行后，在mysql，hibernate 数据库中可看见 User 表和 Room 表都增加了一条记录。
存在问题：如果 Room 表已经存在某个 id 值的记录，而增加的 User 记录的 id 将会是此 id 值，将会抛出异常：java.sql.BatchUpdateException: Duplicate entry ...。这是因为 Room 的 id 是根据 User 的 id 来的。如果新增加的 id 在 Room 表中已经存在，就会抛出 SQL 异常。您可以试验，上面步骤成功后，只将表 User 清空。这样表 User 的记录 id 自增又会从 1 开始。当重新运行程序时就会抛出异常。
-----------------------------------------------------------------------------------------------------------------------------------------------
这篇文章是从网上搜索到的，原因是自己的工程当时遇见一个问题，我这边的机器人服务器的Hibernate和另外一边的PHP公用一个数据库的两张表：
uchome_blog：
blogid mediumint(8) unsigned not null
uid mediumint(8) unsigned not null
username char(15) not null
....
uchome_blogfield
blogid mediumint(8) unsigned not null
uid mediumint(8) unsigned not null
message mediumtext not null
.....
现在的情况是：上面两张表关系是一对一，其中，blogfield的主键参照blog的主键，字段名字和值都是相同的，操作中保持级联更新删除。
数据库是MySQL5，配置文件<因为我负责机器人部分去了，我整完框架，这部分就有另外一个同事去做了，配置文件是他写的>：
<class name="UchomeBlog" table="uchome_blog" catalog="stage_uhome">
<id name="blogid" type="java.lang.Integer">
<column name="blogid" />
<generator class="increment" />
</id>
<property name="uid" type="java.lang.Integer">
<column name="uid" not-null="true" />
</property>
<property name="username" type="java.lang.String">
<column name="username" length="15" not-null="true" />
</property>
<property name="subject" type="java.lang.String">
<column name="subject" length="80" not-null="true" />
</property>
<property name="classid" type="java.lang.Short">
<column name="classid" not-null="true" />
</property>
<property name="viewnum" type="java.lang.Integer">
<column name="viewnum" not-null="true" />
</property>
<property name="replynum" type="java.lang.Integer">
<column name="replynum" not-null="true" />
</property>
<property name="tracenum" type="java.lang.Integer">
<column name="tracenum" not-null="true" />
</property>
<property name="dateline" type="long">
<column name="dateline" not-null="true" />
</property>
<property name="pic" type="java.lang.String">
<column name="pic" length="120" not-null="true" />
</property>
<property name="picflag" type="java.lang.Byte">
<column name="picflag" not-null="true" />
</property>
<property name="noreply" type="java.lang.Byte">
<column name="noreply" not-null="true" />
</property>
<property name="friend" type="java.lang.Byte">
<column name="friend" not-null="true" />
</property>
<property name="password" type="java.lang.String">
<column name="password" length="10" not-null="true" />
</property>
<one-to-one name="blogfield"
class="UchomeBlogfield"
cascade="all"/>
</class>
<class name="UchomeBlogfield" table="uchome_blogfield" catalog="stage_uhome">
<id name="blogid" column="blogid" unsaved-value="0">
<generator class="foreign">
<param name="property">blog</param>
</generator>
</id>
<property name="uid" type="java.lang.Integer">
<column name="uid" not-null="true" />
</property>
<property name="tag" type="java.lang.String">
<column name="tag" not-null="true" />
</property>
<property name="message" type="java.lang.String">
<column name="message" length="16777215" not-null="true" />
</property>
<property name="postip" type="java.lang.String">
<column name="postip" length="20" not-null="true" />
</property>
<property name="related" type="java.lang.String">
<column name="related" length="65535" not-null="true" />
</property>
<property name="relatedtime" type="long">
<column name="relatedtime" not-null="true" />
</property>
<property name="targetIds" type="java.lang.String">
<column name="target_ids" length="65535" not-null="true" />
</property>
<one-to-one name="blog"
class="UchomeBlog"
constrained="true"/>
</class>
工程能跑起来，开始操作也正常，保存了几次之后，抛出异常：
2009-09-18 10:13:53,312 - 3056875 [pool-1-thread-1] WARN org.hibernate.util.JDBCExceptionReporter - SQL Error: 1062, SQLState: 23000
2009-09-18 10:13:53,312 - 3056875 [pool-1-thread-1] ERROR org.hibernate.util.JDBCExceptionReporter - Duplicate entry '6659' for key 'PRIMARY'
2009-09-18 10:13:53,328 - 3056891 [pool-1-thread-1] ERROR org.hibernate.event.def.AbstractFlushingEventListener - Could not synchronize database state with session
org.hibernate.exception.ConstraintViolationException: Could not execute JDBC batch update
at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:71)
at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:249)
at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:235)
at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:139)
at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:298)
at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:27)
at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1000)
at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:338)
at org.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:106)
at org.springframework.orm.hibernate3.HibernateTransactionManager.doCommit(HibernateTransactionManager.java:575)
at org.springframework.transaction.support.AbstractPlatformTransactionManager.processCommit(AbstractPlatformTransactionManager.java:651)
at org.springframework.transaction.support.AbstractPlatformTransactionManager.commit(AbstractPlatformTransactionManager.java:621)
at org.springframework.transaction.interceptor.TransactionAspectSupport.commitTransactionAfterReturning(TransactionAspectSupport.java:311)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:117)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:161)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:203)
at $Proxy5.publishBlog(Unknown Source)
at sun.reflect.GeneratedMethodAccessor65.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:304)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:172)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:139)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:107)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:161)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:203)
at $Proxy6.publishBlog(Unknown Source)
at sun.reflect.GeneratedMethodAccessor65.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:304)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:172)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:139)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:107)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:161)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:203)
at $Proxy6.publishBlog(Unknown Source)
at com.iouyou.robot.model.helper.MessageProcesser.processMsg(MessageProcesser.java:156)
at com.iouyou.robot.model.QQRobotModel.handleCommonsMessage(QQRobotModel.java:238)
at com.iouyou.robot.model.QQRobotModel.receivedCommonsMessage(QQRobotModel.java:198)
at com.iouyou.robot.model.QQRobotModel.qqEvent(QQRobotModel.java:129)
at edu.tsinghua.lumaqq.qq.QQClient.fireQQEvent(QQClient.java:1084)
at edu.tsinghua.lumaqq.qq.BasicFamilyProcessor.processReceiveIM(BasicFamilyProcessor.java:1836)
at edu.tsinghua.lumaqq.qq.BasicFamilyProcessor.packetArrived(BasicFamilyProcessor.java:275)
at edu.tsinghua.lumaqq.qq.ProcessorRouter.packetArrived(ProcessorRouter.java:64)
at edu.tsinghua.lumaqq.qq.QQClient.firePacketArrivedEvent(QQClient.java:1073)
at edu.tsinghua.lumaqq.qq.PacketEventTrigger.call(PacketEventTrigger.java:47)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
at java.util.concurrent.FutureTask.run(FutureTask.java:138)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:98)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:207)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:619)
Caused by: java.sql.BatchUpdateException: Duplicate entry '6659' for key 'PRIMARY'
at com.mysql.jdbc.PreparedStatement.executeBatchSerially(PreparedStatement.java:1669)
at com.mysql.jdbc.PreparedStatement.executeBatch(PreparedStatement.java:1085)
at sun.reflect.GeneratedMethodAccessor64.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.logicalcobwebs.proxool.ProxyStatement.invoke(ProxyStatement.java:100)
at org.logicalcobwebs.proxool.ProxyStatement.intercept(ProxyStatement.java:57)
at $java.sql.Statement$$EnhancerByProxool$$7b04b7fe.executeBatch(<generated>)
at org.hibernate.jdbc.BatchingBatcher.doExecuteBatch(BatchingBatcher.java:48)
at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:242)
... 52 more
Hibernate 我一般只是当作框架来用，很少深入框架本身里面一些东西，这个错误以前没遇见过。说是主键重复，可是到数据库查那个重复的主键，查不到数据，感觉有点奇怪，而且服务器跑起来之后，是保存了几条记录之后才出现这个问题的。
搜索了一下，于是搜索到上面转贴的帖子，大概理解了一下。于是尝试把映射文件的generator改称为native（在我用Hibernate和MySQL的经历中，从来都是用native的）映射文件如下：
<class name="UchomeBlog" table="uchome_blog" catalog="stage_uhome">
<id name="blogid" type="java.lang.Integer">
<column name="blogid" />
<generator class="native" />
</id>
<property name="uid" type="java.lang.Integer">
<column name="uid" not-null="true" />
</property>
<property name="username" type="java.lang.String">
<column name="username" length="15" not-null="true" />
</property>
<property name="subject" type="java.lang.String">
<column name="subject" length="80" not-null="true" />
</property>
<property name="classid" type="java.lang.Short">
<column name="classid" not-null="true" />
</property>
<property name="viewnum" type="java.lang.Integer">
<column name="viewnum" not-null="true" />
</property>
<property name="replynum" type="java.lang.Integer">
<column name="replynum" not-null="true" />
</property>
<property name="tracenum" type="java.lang.Integer">
<column name="tracenum" not-null="true" />
</property>
<property name="dateline" type="long">
<column name="dateline" not-null="true" />
</property>
<property name="pic" type="java.lang.String">
<column name="pic" length="120" not-null="true" />
</property>
<property name="picflag" type="java.lang.Byte">
<column name="picflag" not-null="true" />
</property>
<property name="noreply" type="java.lang.Byte">
<column name="noreply" not-null="true" />
</property>
<property name="friend" type="java.lang.Byte">
<column name="friend" not-null="true" />
</property>
<property name="password" type="java.lang.String">
<column name="password" length="10" not-null="true" />
</property>
<one-to-one name="blogfield"
class="UchomeBlogfield"
cascade="all"/>
</class>
<class name="UchomeBlogfield" table="uchome_blogfield" catalog="stage_uhome">
<id name="blogid" column="blogid" unsaved-value="0">
<generator class="foreign">
<param name="property">blog</param>
</generator>
</id>
<property name="uid" type="java.lang.Integer">
<column name="uid" not-null="true" />
</property>
<property name="tag" type="java.lang.String">
<column name="tag" not-null="true" />
</property>
<property name="message" type="java.lang.String">
<column name="message" length="16777215" not-null="true" />
</property>
<property name="postip" type="java.lang.String">
<column name="postip" length="20" not-null="true" />
</property>
<property name="related" type="java.lang.String">
<column name="related" length="65535" not-null="true" />
</property>
<property name="relatedtime" type="long">
<column name="relatedtime" not-null="true" />
</property>
<property name="targetIds" type="java.lang.String">
<column name="target_ids" length="65535" not-null="true" />
</property>
<one-to-one name="blog"
class="UchomeBlog"
constrained="true"/>
</class>
跑一下，OK。于是不停的测试，不停的发保存记录。跑到了现在几个小时过去，还是没问题。看来问题是在这里了。
但是具体的详细问题出现的原因在哪里，还不知道。现在列出hibernate3中关于主键映射到底是native还是increment的描述：
increment：用于为long, short或者int类型生成 唯一标识。只有在没有其他进程往同一张表中插入数据时才能使用。 在集群下不要使用。
native：根据底层数据库的能力选择identity, sequence 或者hilo中的一个。
关于increment的试用，Hibernate API里面说的如此清楚了，呵呵。
内容来自用户分享和网络整理，不保证内容的准确性，如有侵权内容，可联系管理员处理 
相关文章推荐
- Hibernate关系映射级别注解（一对一双向外键关联、一对一双向外键联合主键）
- 3、Hibernate一对一、一对多、多对多对应关系
- Hibernate之对象关系映射05一对一双向主键关联
- hibernate主键相同的一对一关系
- 我的hibernate之旅~一对一关系映射
- hibernate关系映射--双向一对一@OneToOne
- hibernate 一对一（级联关系）
- Hibernate 关系映射 ——双向一对一
- Hibernate关系映射 一对一双向外键关联@OneToOne Annotation方式 双向关联和单向关联的区别
- Hibernate表关系映射之一对一映射
- Hibernate关系映射（一）一对一单向外键关联@OneToOne Annotation方式
- Hibernate 一对一关系知识点。
- hibernate关系映射管理(一对多，多对一，一对一，多对多)
- hibernate一对一对应关系
- hibernate——一对一、多对一和多对多关系的比较
- hibernate级联关系 -----一对一
- 3、Hibernate一对一、一对多、多对多对应关系
- 3、Hibernate一对一、一对多、多对多对应关系
- 3、Hibernate一对一、一对多、多对多对应关系
- 3、Hibernate一对一、一对多、多对多对应关系