今天在使用hibernate注解方式标明的实体类时产生数据库表示遇到了一些问题，经过搜集一些资料，最后总结了一下，如下所示：
先把我的整体的几个文件的代码贴出来吧
这是hibernate.cfg.xml文件
<?xml version='1.0' encoding='UTF-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<!-- Generated by MyEclipse Hibernate Tools. -->
<hibernate-configuration>
<session-factory>
<property>com.mysql.jdbc.Driver</property>
<property>jdbc:mysql://localhost:3306/phn_dsjava</property>
<property>root</property>
<property>123456</property>
<property>org.hibernate.dialect.MySQLDialect</property>
<property>true</property>
<property>true</property>
<property>update</property>
<mapping/>
</session-factory>
</hibernate-configuration>
这是实体类Announces.java
package com.phn.bean;
import java.util.Date;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;
/**
* @author phn
*
*/
@Entity
@Table(name = "t_announce")
public class Announces {
private Integer id;
private String announcement;
private String title;
private Date thetime;
@Id
@GeneratedValue
@Column(nullable = false)
public Integer getId() {
return this.id;
}
public void setId(Integer id) {
this.id = id;
}
@Column(length = 20000)
public String getAnnouncement() {
return this.announcement;
}
public void setAnnouncement(String announcement) {
this.announcement = announcement;
}
@Column(length = 100)
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public Date getThetime() {
return thetime;
}
public void setThetime(Date thetime) {
this.thetime = thetime;
}
}
这是测试类HibernateAnnotationTest.java
package com.phn.junitTest;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.AnnotationConfiguration;
import org.junit.Test;
import junit.framework.TestCase;
public class HibernateAnnotationTest extends TestCase {
@Test
public void testSQL() {
AnnotationConfiguration configuration = new AnnotationConfiguration();
configuration.configure();
SessionFactory sessionFactory = configuration.buildSessionFactory();
}
}
---------------------------下面是大致问题解释---------------------------
Hibernate的配置文件hibernate.cfg.xml位于src目录下。在单元测试时，执行下面代码时，会产生异常。
Configuration cfg = new Configuration();
SessionFactory sf = cfg.configure().buildSessionFactory();
异常：
org.hibernate.MappingException: An AnnotationConfiguration instance is required to use <mapping/>
Hibernate配置文件中，若带有<mapping/>，则说明映射类时，采用了Annotation方式。在初始化Configuation时，应使用AnnoationConfiguration，代码如下：
AnnotationConfiguration configuration = new AnnotationConfiguration();
configuration.configure();
SessionFactory sessionFactory = configuration.buildSessionFactory();
注意：这里使用的hibernate版本是3.3
版本低一点可能会出现下面图片这个错误，这是因为低版本的hibernate的jar包org.hibernate.engine.query.sql.NativeSQLQueryReturn类缺少，因此将其版本更新一下就行了
