学步园

1.jpa的环境配置  

a.导入jpa所用的jar包，根据jpa的实现框架不同，其jar包也不同  

b.新建如下配置文件src/META-INF/persistence.xml的配置文件

src下必须有一个META-INF文件夹，而且persistence.xml必须在其内,文件名必须相同。

<?xml version="1.0"?>
<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="zsm" transaction-type="RESOURCE_LOCAL">
      <properties>
         <property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect"/>
         <property name="hibernate.connection.driver_class" value="com.mysql.jdbc.Driver"/>
         <property name="hibernate.connection.username" value="root"/>
         <property name="hibernate.connection.password" value="123"/>
         <property name="hibernate.connection.url" value="jdbc:mysql://localhost:3306/eshop?useUnicode=true&characterEncoding=UTF-8"/>
         <property name="hibernate.max_fetch_depth" value="3"/>
         <property name="hibernate.hbm2ddl.auto" value="update"/>
         <property name="hibernate.show_sql" value="true"/>
	     <property name="hibernate.format_sql" value="false"/>
      </properties>
   </persistence-unit>
</persistence>

c.测试jpa环境(jpa的入口是Persistence类):

package com.bean.product;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;

@Entity
public class ProductType {
	
	private int id;
	@Id
	@GeneratedValue(strategy = GenerationType.AUTO)
	public int getId() {
		return id;
	}

	public void setId(int id) {
		this.id = id;
	}
	

}

package com.test;

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

import org.junit.BeforeClass;
import org.junit.Test;

import com.bean.product.ProductType;

public class ProdutctTest {

	@BeforeClass
	public static void setUpBeforeClass() throws Exception {
	}

	@Test
	public void test() {
		EntityManagerFactory factory = Persistence.createEntityManagerFactory("zsm");
		EntityManager em = factory.createEntityManager();
		em.getTransaction().begin();
		em.persist(new ProductType());
		em.getTransaction().commit();
		em.close();
		factory.close();
	}

}