JPA的问题（寻求帮助，谢谢：））

Question

第一次用这个，公司里是orcal数据库。我现在用mysql，请问有哪些地方需要改的，我自己改了半天还是异常不断，一直都是生成策略异常
代码如下：请教怎么改？谢谢：）package com.hsk.db.web.pojo;import java.util.Date;import javax.persistence.Column;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Temporal;
import javax.persistence.TemporalType;@org.hibernate.annotations.Entity(selectBeforeUpdate = true, dynamicInsert = true, dynamicUpdate = true)
@javax.persistence.Entity
@javax.persistence.Table(name = "ecg_v1_data3")
 @javax.persistence.SequenceGenerator(name = "V1_DATA_CODE", initialValue = 100, sequenceName = "SEQ_ECGDATAV1", allocationSize = 1)public class Ecgdatav1 {
// V1_DATA_CODE NUMBER(20) 数据编码流水号
// V1_DATA_TIME TIMESTAMP(6) Y 数据采集时间
// V1_DATA_VALUE NUMBER(5,2) Y 数据值
// DATA_CODE NUMBER(10) 数据编码

@Id
 
 @GeneratedValue(strategy = GenerationType.IDENTITY, generator = "V1_DATA_CODE")
@Column(name="V1_DATA_CODE", unique=true, nullable=false, insertable=true, updatable=true) 
private int   v1_data_code ; 

@Temporal(TemporalType.TIMESTAMP) 
@Column(name = "V1_DATA_TIME")
private Date v1_data_time;

@Column(name = "V1_DATA_VALUE")
private int v1_data_value;
@Column(name = "DATA_CODE")
private int  data_code;
public int getV1_data_code() {
return v1_data_code;
}
public void setV1_data_code(int v1_data_code) {
this.v1_data_code = v1_data_code;
}
public Date getV1_data_time() {
return v1_data_time;
}
public void setV1_data_time(Date v1_data_time) {
this.v1_data_time = v1_data_time;
}
public int getV1_data_value() {
return v1_data_value;
}
public void setV1_data_value(int v1_data_value) {
this.v1_data_value = v1_data_value;
}
public int getData_code() {
return data_code;
}
public void setData_code(int data_code) {
this.data_code = data_code;
} 
 }

Answer 1

看下什么异常@GeneratedValue(strategy = GenerationType.AUTO) 这个式下.

Answer 2

Oracle 没有什么 IDENTITY，要用 SEQUENCE

Answer 3

原先是SEQUENCE
我用的是mysql，所以改成了IDENTITY。。
但是还是报异常

Answer 4

2010-07-24 17:31:52,750 ERROR [org.springframework.web.context.ContextLoader] - <Context initialization failed>
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sessionFactory' defined in file [D:\Program Files\apache-tomcat-6.0.18\webapps\hskdbweb\WEB-INF\classes\spring\applicationContext.xml]: Invocation of init method failed; nested exception is org.hibernate.MappingException: could not instantiate id generator
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1338)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:473)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory$1.run(AbstractAutowireCapableBeanFactory.java:409)
at java.security.AccessController.doPrivileged(Native Method)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:380)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:264)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:261)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:185)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:164)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:423)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:728)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:380)
at org.springframework.web.context.ContextLoader.createWebApplicationContext(ContextLoader.java:255)
at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:199)
at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:45)
at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:3843)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4342)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:791)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:771)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:525)
at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:926)
at org.apache.catalina.startup.HostConfig.deployDirectories(HostConfig.java:889)
at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:492)
at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1149)
at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:311)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1053)
at org.apache.catalina.core.StandardHost.start(StandardHost.java:719)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1045)
at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:443)
at org.apache.catalina.core.StandardService.start(StandardService.java:516)
at org.apache.catalina.core.StandardServer.start(StandardServer.java:710)
at org.apache.catalina.startup.Catalina.start(Catalina.java:578)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:288)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:413)
Caused by: org.hibernate.MappingException: could not instantiate id generator
at org.hibernate.id.IdentifierGeneratorFactory.create(IdentifierGeneratorFactory.java:98)
at org.hibernate.mapping.SimpleValue.createIdentifierGenerator(SimpleValue.java:152)
at org.hibernate.impl.SessionFactoryImpl.<init>(SessionFactoryImpl.java:192)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1218)
at org.hibernate.cfg.AnnotationConfiguration.buildSessionFactory(AnnotationConfiguration.java:867)
at org.springframework.orm.hibernate3.LocalSessionFactoryBean.newSessionFactory(LocalSessionFactoryBean.java:814)
at org.springframework.orm.hibernate3.LocalSessionFactoryBean.buildSessionFactory(LocalSessionFactoryBean.java:732)
at org.springframework.orm.hibernate3.AbstractSessionFactoryBean.afterPropertiesSet(AbstractSessionFactoryBean.java:211)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1369)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1335)
... 39 more
Caused by: org.hibernate.MappingException: Dialect does not support sequences
at org.hibernate.dialect.Dialect.getSequenceNextValString(Dialect.java:570)
at org.hibernate.id.SequenceGenerator.configure(SequenceGenerator.java:65)
at org.hibernate.id.IdentifierGeneratorFactory.create(IdentifierGeneratorFactory.java:94)
... 48 more
2010-7-24 17:31:52 org.apache.catalina.core.StandardContext listenerStart