Spring整合JPA

虽然JPA开发大多使用hibernate规范来进行，但是和spring整合这一块却存在明显的差异，先来看下spring整合jpa的重要配置

<context:annotation-config />
<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
    <property name="dataSource" ref="dataSource" />
    <property name="jpaVendorAdapter">
    <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
		<property name="showSql" value="false" /></bean>
    </property>
    <property name="jpaProperties">
	<props>
		<prop key="hibernate.hbm2ddl.auto">update</prop>
	</props>
   </property>
</bean>
<!-- 如果没有数据源可以使用如下配置 -->
<!--  <bean id="entityManager"  class="org.springframework.orm.jpa.LocalEntityManagerFactoryBean">  
        <property name="persistenceUnitName" value="mengya"></property>  
</bean> -->
<bean class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor" />
<bean id="txManager" class="org.springframework.orm.jpa.JpaTransactionManager">
	<property name="entityManagerFactory" ref="entityManagerFactory" />
</bean>
<tx:annotation-driven transaction-manager="txManager" />

<?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">
	<!-- name属性随意-->
	<persistence-unit name="springmvc" />
</persistence>

接下来就是数据源了，我习惯使用dbcp的数据源配置大致如下：

<?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:tx="http://www.springframework.org/schema/tx"
	xsi:schemaLocation="http://www.springframework.org/schema/beans
           http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
           http://www.springframework.org/schema/context
           http://www.springframework.org/schema/context/spring-context-2.5.xsd
           http://www.springframework.org/schema/tx 
           http://www.springframework.org/schema/tx/spring-tx-2.5.xsd">
           
        <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
			<property name="driverClassName" value="org.gjt.mm.mysql.Driver" />
			<property name="url" value="jdbc:mysql://localhost:3306/exercise?useUnicode=true&characterEncoding=UTF-8" />
			<property name="username" value="root" />
			<property name="password" value="123456" />
			<!-- 连接池启动时的初始值 -->
			<property name="initialSize" value="1" />
			<!-- 连接池的最大值 -->
			<property name="maxActive" value="500" />
			<!-- 最大空闲值.当经过一个高峰时间后，连接池可以慢慢将已经用不到的连接慢慢释放一部分，一直减少到maxIdle为止 -->
			<property name="maxIdle" value="2" />
			<!-- 最小空闲值.当空闲的连接数少于阀值时，连接池就会预申请去一些连接，以免洪峰来时来不及申请 -->
			<property name="minIdle" value="1" />
        </bean> 
        
</beans>

    @PersistenceContext private EntityManager entityManager = null;
	
    @Transactional(propagation=Propagation.REQUIRED)
    public void save(User u) {
    	entityManager.persist(u);	
    }
    @Transactional(propagation=Propagation.REQUIRED)
    public void updateUser(User u) {
       	entityManager.merge(u);
   		
    }

#
# Log4J Settings for log4j 1.2.x (via jakarta-commons-logging)
#
# The five logging levels used by Log are (in order):
#
#   1. DEBUG (the least serious)
#   2. INFO
#   3. WARN
#   4. ERROR
#   5. FATAL (the most serious)


# Set root logger level to WARN and append to stdout
log4j.rootLogger=DEBUG, stdout
#info
#DEBUG
#ERROR

log4j.appender.stdout=org.apache.log4j.ConsoleAppender

#log4j.appender.stdout=org.apache.log4j.FileAppender
#log4j.appender.stdout.File=d:\\logs.log 
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout

# Pattern to output the caller's file name and line number.
log4j.appender.stdout.layout.ConversionPattern=%d %5p (%c:%L) - %m%n

# Print only messages of level ERROR or above in the package noModule.
log4j.logger.noModule=ERROR

# OpenSymphony Stuff
log4j.logger.com.opensymphony=ERROR
log4j.logger.freemarker=ERROR
log4j.logger.org.hibernate.jdbc=DEBUG

#org.hibernate.SQL  
#org.hibernate.type   
#org.hibernate.tool.hbm2ddl  
#org.hibernate.pretty   
#org.hibernate.cache   
#org.hibernate.transaction  
#org.hibernate.jdbc    
#org.hibernate.hql.AST   
#org.hibernate.secure

# Spring Stuff
log4j.logger.org.springframework=ERROR

Spring整合JPA

原文：http://blog.csdn.net/walkcode/article/details/39267783