hibernate+junit测试实体类生成数据库表

谁践踏了优雅 2022-08-27 13:58 191阅读 0赞

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">
    
    <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

![SouthEast][]

[SouthEast]: /images/20220823/745d3b33b23b427fa3e58e75c12e3305.png