jpa 应用 创建EntityManagerFactory失败

[pbkok]

高手们快帮帮我吧

Persistence.xml

<?xml version="1.0" encoding="UTF-8"?>
<persistence xmlns="http://java.sun.com/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence
http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd"
version="1.0">

<persistence-unit name="demo" transaction-type="RESOURCE_LOCAL">
<provider>org.hibernate.ejb.HibernatePersistence</provider>
<properties>
<!-- 连接参数 -->
<property name="hibernate.dialect" value="org.hibernate.dialect.MySQL5Dialect" />
<property name="hibernate.connection.driver_class" value="com.mysql.jdbc.Driver" />
<property name="hibernate.connection.username" value="root" />
<property name="hibernate.connection.password" value="admin@123" />
<property name="hibernate.connection.url"
value="jdbc:mysql://localhost:3306/jsfjpa?useUnicode=true&characterEncoding=UTF-8" />

<!-- 数据源设置 -->
<property name="hibernate.max_fetch_depth" value="3" />
<property name="hibernate.hbm2ddl.auto" value="update" />
<property name="hibernate.jdbc.fetch_size" value="50" />
<property name="hibernate.jdbc.batch_size" value="10" />
<property name="hibernate.show_sql" value="true" />
<property name="hibernate.format_sql" value="true" />
</properties>
</persistence-unit>

</persistence>

Persion实体类

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;
@Entity  
@Table(name="persion")  
public class Persion {  
    @Id  
    @GeneratedValue(strategy = GenerationType.IDENTITY)  
    private java.lang.Long userid;  
    private java.lang.String name;  
     
     
    public java.lang.Long getUserid() {  
        return userid;  
    }  
    public void setUserid(java.lang.Long userid) {  
        this.userid = userid;  
    }  
    public java.lang.String getName() {  
        return name;  
    }  
    public void setName(java.lang.String name) {  
        this.name = name;  
    }  
      
} 

servlet类

import java.io.IOException;

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.EntityTransaction;
import javax.persistence.Persistence;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.pbk.entity.Persion;

public class Start extends HttpServlet{
	 public void doGet(HttpServletRequest request, HttpServletResponse response)  
	   throws ServletException, IOException {
		   EntityManagerFactory entityfactory = null;  
		   EntityTransaction  t=null;  
		   EntityManager em=null;  
		  try{  
		   entityfactory = Persistence.createEntityManagerFactory("demo");  
		   em=entityfactory.createEntityManager();    
		     
		     
		      t=em.getTransaction();  
		   t.begin();  
		   Persion p=new Persion();  
		   p.setName("abc");  
		   em.persist(p);  
		   t.commit();  
		  }catch(Exception e){  
		   e.printStackTrace();   
		  }  
		  em.close();  
		  entityfactory.close();  
		 }
	 
}

输入请求地址控制台报错
javax.persistence.PersistenceException: No Persistence provider for EntityManager named demo
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:56)
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:34)
at com.pbk.action.Start.doGet(Start.java:23)
...........
我又写了一个Test类
直接在main方法里运行就没错

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;

import com.pbk.entity.Persion;

public class Test {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
        try {
			EntityManagerFactory emf =  Persistence  
				.createEntityManagerFactory("demo");  
			EntityManager em = emf.createEntityManager();  
			em.getTransaction().begin();    
			Persion p=new Persion();  
			p.setName("af");
			em.persist(p);  
			em.getTransaction().commit();  
			em.close();
		} catch (Exception e) {

			e.printStackTrace();
		}
	}

}

这是什么原因啊

[pbkok]

没人解决吗，快来高手啊

[花谢尊前不敢香]

没有hibernate-entitymanager.jar包？

[forgetsam]

Persistence.xml放错地方了。

[pbkok]

有hibernate-entitymanager.jar这个包 Persistence.xml也没放错地方 我前边有一个Test类 用main方法就可以插入数据 但是通过网页访问servlet就不行啊

[神探狄仁杰]

应该是Persistence.xml这个文件，没有加载。

[pbkok]

我也很纳闷，为什么通过main方法调用就没事

[神探狄仁杰]

你是怎么引入jar的，是不是少了jar的缘故呢

[pbkok]

antlr-2.7.6.jar commons-collections-3.1.jar dom4j-1.6.1.jar ejb3-persistence.jar hibernate3.jar hibernate-annotations.jar hibernate-cglib-repack-2.1_3.jar hibernate-commons-annotations.jar hibernate-entitymanager.jar javassist-3.4.GA.jar jta-1.1.jar log4j.jar mysql-connector-java-5.1.16-bin.jar slf4j-api-1.5.2.jar slf4j-log4j12.jar 把这些包放到WEB-INF/lib下了

[pbkok]

谁能测试一下，看会不会出现同样错误

[xizhou704]

自己测试了一下，发现没出现错误

[pbkok]

[pbkok]

引用 10 楼 xizhou704 的回复:

自己测试了一下，发现没出现错误

你有没有改什么东西，直接用上面的代码吗

[GHOST64]

我也遇到这个问题。。结果发现是persistence.xml放错位置