a.导入spring所用jar包
b.新建src/beans.xml文件
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd"> <aop:aspectj-autoproxy/> <context:component-scan base-package="com"/> <!-- 使用数据源和指定persistence.xml位置的方式创建entityManagerFactory,如果使用的不是hibernate JPA实现, 需要在tomcat作一些特殊配置.具体参考手册 注意:使用该方式需要把persistence.xml中的hibernate.connection.driver_class,hibernate.connection.username,hibernate.connection.password,hibernate.connection.url配置删除 --> <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close"> <property name="driverClassName" value="com.mysql.jdbc.Driver"/> <property name="url" value="jdbc:mysql://localhost:3306/eshop?useUnicode=true&characterEncoding=UTF-8"/> <property name="username" value="root"/> <property name="password" value="123"/> <!-- 初始化时获取的连接数,取值应在minPoolSize与maxPoolSize之间。Default: 3 --> </bean> <bean id="emf" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean"> <property name="dataSource" ref="dataSource"/> <property name="persistenceXmlLocation" value="classpath:META-INF/persistence.xml"/> <property name="loadTimeWeaver"> <bean class="org.springframework.instrument.classloading.InstrumentationLoadTimeWeaver"/> </property> </bean> <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager"> <property name="entityManagerFactory" ref="emf"/> </bean> <tx:annotation-driven transaction-manager="transactionManager"/> </beans>
<?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"> <provider>org.hibernate.ejb.HibernatePersistence</provider> <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>
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.sql.DataSource; import org.junit.BeforeClass; import org.junit.Test; import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext; public class ProdutctTest { @BeforeClass public static void setUpBeforeClass() throws Exception { } @Test public void test() { ApplicationContext acx = new ClassPathXmlApplicationContext("beans.xml"); DataSource dataSource = (DataSource)acx.getBean("dataSource"); System.out.println(dataSource); } }
这里,列一些使用JPA常见的问题,算是自己的笔记,希望可以帮到你的小忙。
1、jpa包的冲突
2、事务不正常执行
3、Cannot proxy target class because CGLIB2 is not available
1、jpa包的冲突
运行 jpa 程序,却出现:
Caused by: java.lang.NoSuchMethodError: javax.persistence.spi.PersistenceUnitInfo.getValidationMode()Ljavax/persistence/ValidationMode;
这个是由于jar包的冲突了, 因为使用的是新版本的 Hibernate(这里我使用的是 Hibernate 3.6),跟 javaee.jar 里面的jpa接口冲突了
解决办法
使用 tomcat 中带的 servlet-api.jar 替换 javaee.jar
去掉 Java EE 5 Libraries
新建 user libraries 包含 jsf-api.jar jsf-impl.jar jstl-1.2.jar servlet-api.jar
就是将 MyEclipse 里面的 Java EE 5 Libraries 中的 javaee.jar 换成 servlet-api.jar
然后在工程里加入刚刚的user libraries,OK
org.gjt.mm.mysql.Driver是早期的驱动名称,后来就改名为com.mysql.jdbc.Driver,现在一般都推荐使用com.mysql.jdbc.Driver。在最新版本的mysql jdbc驱动中,为了保持对老版本的兼容,仍然保留了org.gjt.mm.mysql.Driver,但是实际上org.gjt.mm.mysql.Driver中调用了com.mysql.jdbc.Driver,因此现在这两个驱动没有什么区别。