hibernate+junit测试实体类生成数据库表

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 name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
		<property name="hibernate.connection.url">jdbc:mysql://localhost:3306/phn_dsjava</property>
		<property name="hibernate.connection.username">root</property>
		<property name="hibernate.connection.password">123456</property>
		<property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
		<property name="hibernate.show_sql">true</property>
		<property name="format_sql">true</property>
		<property name="hibernate.hbm2ddl.auto">update</property>

		<mapping class="com.phn.bean.Announces"/>

	</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 class="***"/>

Hibernate配置文件中，若带有<mapping class="com.phn.Users"/>，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