1:C3P0数据源的配置、sessionFactory托管给SPRING的配置。
由于C3P0使用比较广泛,下面介绍C3P0在spring和hibernate3配置中的一些常用配置项,首先先把配置文件贴出来先,配置的文件名为dbContext.xml
<?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"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.1.xsd http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-2.0.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.1.xsd">
<context:annotation-config/>
<context:component-scan base-package="cn.bb.entity"/>
<!-- 配置数据源 -->
<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
<!--当连接池中的连接耗尽的时候c3p0一次同时获取的连接数。Default: 3 -->
<property name="acquireIncrement" value="3"></property>
<!--两次连接中间隔时间,单位毫秒。Default: 1000 -->
<property name="acquireRetryDelay" value="1000"/>
<!--连接关闭时默认将所有未提交的操作回滚。Default: false -->
<property name="autoCommitOnClose" value="false"/>
<!--c3p0将建一张名为Test的空表,并使用其自带的查询语句进行测试。如果定义了这个参数那么
属性preferredTestQuery将被忽略。你不能在这张Test表上进行任何操作,它将只供c3p0测试
使用。Default: null-->
<property name="automaticTestTable" value="Test"/>
<!--获取连接失败将会引起所有等待连接池来获取连接的线程抛出异常。但是数据源仍有效
保留,并在下次调用getConnection()的时候继续尝试获取连接。如果设为true,那么在尝试
获取连接失败后该数据源将申明已断开并永久关闭。Default: false-->
<property name="breakAfterAcquireFailure" value="false"/>
<!--当连接池用完时客户端调用getConnection()后等待获取新连接的时间,超时后将抛出
SQLException,如设为0则无限期等待。单位毫秒。Default: 0 -->
<property name="checkoutTimeout" value="0"/>
<!--通过实现ConnectionTester或QueryConnectionTester的类来测试连接。类名需制定全路径。
Default: com.mchange.v2.c3p0.impl.DefaultConnectionTester-->
<!--<property name="connectionTesterClassName" value="cn.bb.entity.Test"></property>-->
<!--指定c3p0 libraries的路径,如果(通常都是这样)在本地即可获得那么无需设置,默认null即可
Default: null-->
<property name="factoryClassLocation" value="null"/>
<!--Strongly disrecommended. Setting this to true may lead to subtle and bizarre bugs.
(文档原文)作者强烈建议不使用的一个属性-->
<property name="forceIgnoreUnresolvedTransactions" value="false"/>
<!--每60秒检查所有连接池中的空闲连接。Default: 0 -->
<property name="idleConnectionTestPeriod" value="60"/>
<!--初始化时获取三个连接,取值应在minPoolSize与maxPoolSize之间。Default: 3 -->
<property name="initialPoolSize" value="3"/>
<!--最大空闲时间,60秒内未使用则连接被丢弃。若为0则永不丢弃。Default: 0 -->
<property name="maxIdleTime" value="60"/>
<!--连接池中保留的最大连接数。Default: 15 -->
<property name="maxPoolSize" value="15"/>
<!--JDBC的标准参数,用以控制数据源内加载的PreparedStatements数量。但由于预缓存的statements
属于单个connection而不是整个连接池。所以设置这个参数需要考虑到多方面的因素。
如果maxStatements与maxStatementsPerConnection均为0,则缓存被关闭。Default: 0-->
<property name="maxStatements" value="100"/>
<!--maxStatementsPerConnection定义了连接池内单个连接所拥有的最大缓存statements数。Default: 0 -->
<property name="maxStatementsPerConnection" value="5"/>
<!--c3p0是异步操作的,缓慢的JDBC操作通过帮助进程完成。扩展这些操作可以有效的提升性能
通过多线程实现多个操作同时被执行。Default: 3-->
<property name="numHelperThreads" value="3"/>
<property name="password" value="postgres"/>
<property name="user" value="postgres"/>
<!--定义所有连接测试都执行的测试语句。在使用连接测试的情况下这个一显著提高测试速度。注意:
测试的表必须在初始数据源的时候就存在。Default: null-->
<!--<property name="preferredTestQuery" value="select id from test where id = 1"></property>-->
<!--用户修改系统配置参数执行前最多等待300秒。Default: 300 -->
<property name="propertyCycle" value="300"/>
<!--因性能消耗大请只在需要的时候使用它。如果设为true那么在每个connection提交的
时候都将校验其有效性。建议使用idleConnectionTestPeriod或automaticTestTable
等方法来提升连接测试的性能。Default: false -->
<property name="testConnectionOnCheckout" value="false"/>
<!--如果设为true那么在取得连接的同时将校验连接的有效性。Default: false -->
<property name="testConnectionOnCheckin" value="true"/>
<!-- postgres jdbc-->
<property name="driverClass" value="org.postgresql.Driver"/>
<property name="jdbcUrl" value="jdbc:postgresql://localhost:5432/testTMP"/>
</bean>
<!--配置sessionFactory-->
<bean id="sessionFactory" class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
<property name="dataSource" ref="dataSource"/>
<!--annotatedPackages 使用annotatedPackages 不生效,使用packagesToScan生效-->
<property name="packagesToScan">
<list>
<value>cn.bb.entity</value>
</list>
</property>
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">org.hibernate.dialect.PostgreSQLDialect</prop>
<prop key="show_sql">true</prop>
<prop key="hibernate.hbm2ddl.auto">update</prop>
</props>
</property>
</bean>
<!--hibernateTemplate已经不推荐使用-->
<!--<bean id="hibernateTemplate" class="org.springframework.orm.hibernate3.HibernateTemplate">-->
<!--<property name="sessionFactory" ref="sessionFactory"/>-->
<!--</bean>-->
</beans>
<context:annotation-config/>
<context:component-scan base-package="cn.bb.entity"/>
这是描述是扫描Entity包的类,也就是我们所说的domain类,orm框架中户数据对于的类
<!--annotatedPackages 使用annotatedPackages 不生效,使用packagesToScan生效-->
<property name="packagesToScan">
<list>
<value>cn.bb.entity</value>
</list>
</property>
这里描述的是采用packagesToScan参数扫描entity,生成数据表。
2:DAO的配置
为了避免框架的侵入,spring不推荐使用hibernateTemplate作为数据访问的入库,而是使用hibernate框架自身的SessionFactory,该SessionFactory在上面dbContext.xml已经配置对应的类是:org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean(具体怎么注入有待研究)。这样在DAO的java代码中只有hibernate框架的代码,而没有spring框架的代码,这样就避免了框架的侵入,职责的单一原则。
package cn.bb.dao;
import cn.bb.entity.Good;
import org.hibernate.SessionFactory;
import java.util.List;
/**
* Created with IntelliJ IDEA.
* User: John
* Date: 14-7-1
* Time: 上午12:52
* To change this template use File | Settings | File Templates.
*/
public class GoodDao {
private SessionFactory sessionFactory;
public SessionFactory getSessionFactory() {
return sessionFactory;
}
public void setSessionFactory(SessionFactory sessionFactory) {
this.sessionFactory = sessionFactory;
}
public List<Good> list() {
return this.sessionFactory.getCurrentSession()
.createCriteria(Good.class)
.list();
}
public void save(Good good) {
this.sessionFactory.getCurrentSession().save(good);
}
public void update(Good good) {
this.sessionFactory.getCurrentSession().update(good);
}
}
上面代码中可以发现数据库操作获取hibernatesession的操作都是采用this.sessionFactory.getCurrentSession(),这是Spring官方推荐的,可以提高性能和控制事务。
3:事务控制
采用以上DAO的编码方式必须引入事务控制,因为this.sessionFactory.getCurrentSession()是在当前绑定事务中获取session,当事务不存在时就会保存,如:
org.hibernate.HibernateException: No Hibernate Session bound to thread, and configuration does not allow creation of non-transactional one here
采用aop配置事务方式为:applicationContext.xml
<?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: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.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd">
<import resource="dbContext.xml"/>
<!--<import resource="security-config.xml"/>-->
<bean id="goodDao" class="cn.bb.dao.GoodDao">
<property name="sessionFactory" ref="sessionFactory"/>
</bean>
<bean id="goodService" class="cn.bb.service.GoodService">
<property name="goodDao" ref="goodDao"/>
</bean>
<bean id="transactionManager" class="org.springframework.orm.hibernate3.HibernateTransactionManager">
<property name="sessionFactory" ref="sessionFactory"/>
</bean>
<aop:config>
<aop:pointcut id="goodServiceMethods" expression="execution(* cn.bb.service.GoodService.*(..))"/>
<aop:advisor advice-ref="txAdvice" pointcut-ref="goodServiceMethods"/>
</aop:config>
<tx:advice id="txAdvice" transaction-manager="transactionManager">
<tx:attributes>
<tx:method name="increasePrice*" propagation="REQUIRED"/>
<tx:method name="save*" propagation="REQUIRED"/>
<tx:method name="*" propagation="SUPPORTS" read-only="true"/>
</tx:attributes>
</tx:advice>
</beans>
这样就对GoodService进行了事务控制
GoodService的代码如下:
package cn.bb.service;
import cn.bb.dao.GoodDao;
import cn.bb.entity.Good;
import java.util.List;
public class GoodService {
private GoodDao goodDao;
public void setGoodDao(GoodDao goodDao) {
this.goodDao = goodDao;
}
public void increasePriceOfAllGood() {
}
public List<Good> getAllGood() {
return goodDao.list();
}
public void saveGood(Good good) {
goodDao.save(good);
}
public void saveGoodBatch(List<Good> goodList) throws Exception{
for(Good good : goodList) {
saveGood(good);
// goodDao.save(good); //都行
}
// throw new Exception("sss"); //不会回滚
throw new RuntimeException("aa"); //会回滚
}
}
在测试用,发现在saveGoodBatch抛出 new Exception 不会产生回滚,抛出 RuntimeException时会发生回滚。
4:注意的东西
事务应该控制到service层,在dao和service中不应该捕获异常,也就是出现try..catch..语句,所有异常都在web层进行处理,这样可以让service层的事务进行回滚,从而避免了数据的不一致。
5:pom.xml
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>SpringTransaction</groupId>
<artifactId>SpringTransaction</artifactId>
<packaging>war</packaging>
<version>1.0-SNAPSHOT</version>
<name>SpringTransaction Maven Webapp</name>
<url>http://maven.apache.org</url>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>jstl</groupId>
<artifactId>jstl</artifactId>
<version>1.2</version>
</dependency>
<!--servlet-->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>servlet-api</artifactId>
<version>2.5</version>
</dependency>
<!--postgresql jdbc-->
<dependency>
<groupId>postgresql</groupId>
<artifactId>postgresql</artifactId>
<version>9.1-901.jdbc4</version>
</dependency>
<!--c3p0-->
<dependency>
<groupId>c3p0</groupId>
<artifactId>c3p0</artifactId>
<version>0.9.0</version>
</dependency>
<!-- Hibernate framework -->
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-nop</artifactId>
<version>1.5.2</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>3.3.2.GA</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-annotations</artifactId>
<version>3.4.0.GA</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-commons-annotations</artifactId>
<version>3.3.0.ga</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-entitymanager</artifactId>
<version>3.4.0.GA</version>
</dependency>
<!-- Hibernate library dependecy start -->
<dependency>
<groupId>dom4j</groupId>
<artifactId>dom4j</artifactId>
<version>1.6.1</version>
</dependency>
<dependency>
<groupId>commons-logging</groupId>
<artifactId>commons-logging</artifactId>
<version>1.1.1</version>
</dependency>
<dependency>
<groupId>commons-collections</groupId>
<artifactId>commons-collections</artifactId>
<version>3.2.1</version>
</dependency>
<dependency>
<groupId>antlr</groupId>
<artifactId>antlr</artifactId>
<version>2.7.7</version>
</dependency>
<dependency>
<groupId>javassist</groupId>
<artifactId>javassist</artifactId>
<version>3.12.1.GA</version>
</dependency>
<!-- Hibernate library dependecy end -->
<!-- Spring 3 dependencies -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-test</artifactId>
<version>3.1.2.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>3.1.2.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>3.1.2.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-web</artifactId>
<version>3.1.2.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>3.1.2.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-orm</artifactId>
<version>3.1.2.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.security</groupId>
<artifactId>spring-security-web</artifactId>
<version>3.1.6.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.security</groupId>
<artifactId>spring-security-config</artifactId>
<version>3.1.6.RELEASE</version>
</dependency>
<!-- QuartzJobBean in spring-context-support.jar -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context-support</artifactId>
<version>3.1.2.RELEASE</version>
</dependency>
<!-- Spring + Quartz need transaction -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-tx</artifactId>
<version>3.1.2.RELEASE</version>
</dependency>
<!-- Quartz framework -->
<dependency>
<groupId>org.quartz-scheduler</groupId>
<artifactId>quartz</artifactId>
<version>1.8.6</version>
</dependency>
<!--commons-net ftpclient-->
<dependency>
<groupId>commons-net</groupId>
<artifactId>commons-net</artifactId>
<version>3.3</version>
</dependency>
<!--log4j-->
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.16</version>
</dependency>
<!-- velocity-->
<dependency>
<groupId>org.apache.velocity</groupId>
<artifactId>velocity</artifactId>
<version>1.5</version>
</dependency>
<!--httpclient-->
<dependency>
<groupId>commons-httpclient</groupId>
<artifactId>commons-httpclient</artifactId>
<version>3.1</version>
</dependency>
<!--spring aop-->
<!--<dependency>-->
<!--<groupId>org.aspectj</groupId>-->
<!--<artifactId>aspectjlib</artifactId>-->
<!--<version>1.6.12</version>-->
<!--</dependency>-->
<dependency>
<groupId>org.aspectj</groupId>
<artifactId>aspectjrt</artifactId>
<version>1.6.12</version>
</dependency>
<dependency>
<groupId>org.aspectj</groupId>
<artifactId>aspectjweaver</artifactId>
<version>1.6.12</version>
</dependency>
</dependencies>
<build>
<finalName>SpringTransaction</finalName>
</build>
</project>