一：今天遇到一个诡异的问题，就是关于hibernate3.x实现表结构自动创建，一般我们在用Struts2，Hibernate3.x，Spring3.x搭建框架，尤其在开发阶段都希望在启动Web容器时就可以根据Bean实体自动创建数据表结构，但是今天发现不行，经过查找，最终解决，现在记录一下：

二：首先是实体Bean类：这里我们以User.java为例：

User.java

package net.lampbrother.survey.domain;import java.util.Date;
import java.util.HashSet;
import java.util.Set;/*** 用户实体*/
public class User {private Integer id;private String email;private String password;private String nickName;private Date regDate = new Date();private Set<Survey> surveys = new HashSet<Survey>();public Integer getId() {return id;}public void setId(Integer id) {this.id = id;}public String getEmail() {return email;}public void setEmail(String email) {this.email = email;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}public String getNickName() {return nickName;}public void setNickName(String nickName) {this.nickName = nickName;}public Date getRegDate() {return regDate;}public void setRegDate(Date regDate) {this.regDate = regDate;}public Set<Survey> getSurveys() {return surveys;}public void setSurveys(Set<Survey> surveys) {this.surveys = surveys;}}

三：接下来是User.hbm.xml文件：

<?xml VERSION="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"><hibernate-mapping><class NAME="net.lampbrother.survey.domain.User" TABLE="USERS"><id NAME="id" TYPE="java.lang.Integer"><COLUMN NAME="USER_ID" /><generator class="native" /></id><property NAME="email" TYPE="java.lang.String"><COLUMN NAME="EMAIL" /></property><property NAME="password" TYPE="java.lang.String"><COLUMN NAME="PASSWORD" /></property><property NAME="nickName" TYPE="java.lang.String"><COLUMN NAME="NICK_NAME" /></property><property NAME="regDate" TYPE="java.util.Date"><COLUMN NAME="REG_DATE" /></property></class></hibernate-mapping>

四：接下来就是hibernate的配置文件：hibernate.cfg.xml

<?xml VERSION="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC"-//Hibernate/Hibernate Configuration DTD 3.0//EN""http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration><SESSION-factory><property NAME="show_sql">TRUE</property><property NAME="format_sql">TRUE</property><property NAME="hbm2ddl.auto">UPDATE</property><!-- 上面的这个不能自动创建表结构 --><!-- 根据Bean自动生成数据库表,MySql5.5以后要使用org.hibernate.dialect.MySQL5InnoDBDialect才能创建成功！ --><!-- <property name="dialect">org.hibernate.dialect.MySQLInnoDBDialect</property> --><property NAME="dialect">org.hibernate.dialect.MySQL5InnoDBDialect</property><property NAME="jdbc.fetch_size">200</property><property NAME="jdbc.batch_size">50</property>    <!-- 加入 Hibernate 映射文件 --><mapping resource="net/lampbrother/survey/domain/User.hbm.xml"/></SESSION-factory></hibernate-configuration>

五：究其原因是：MySQL5.5版本以后就不能用：org.hibernate.dialect.MySQLInnoDBDialect方言来实现自动建表了，必须改用：org.hibernate.dialect.MySQL5InnoDBDialect来实现自动建表。