1:C3P0數據源的配置、sessionFactory託管給SPRING的配置。
由於C3P0使用比較廣泛,下面介紹C3P0在spring和hibernate3配置中的一些常用配置項,首先先把配置文件貼出來先,配置的文件名爲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"/> <!-- 配置數據源 --> <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource"> <!--當連接池中的連接耗盡的時候c3p0一次同時獲取的連接數。Default: 3 --> <property name="acquireIncrement" value="3"></property> <!--兩次連接中間隔時間,單位毫秒。Default: 1000 --> <property name="acquireRetryDelay" value="1000"/> <!--連接關閉時默認將所有未提交的操作回滾。Default: false --> <property name="autoCommitOnClose" value="false"/> <!--c3p0將建一張名爲Test的空表,並使用其自帶的查詢語句進行測試。如果定義了這個參數那麼 屬性preferredTestQuery將被忽略。你不能在這張Test表上進行任何操作,它將只供c3p0測試 使用。Default: null--> <property name="automaticTestTable" value="Test"/> <!--獲取連接失敗將會引起所有等待連接池來獲取連接的線程拋出異常。但是數據源仍有效 保留,並在下次調用getConnection()的時候繼續嘗試獲取連接。如果設爲true,那麼在嘗試 獲取連接失敗後該數據源將申明已斷開並永久關閉。Default: false--> <property name="breakAfterAcquireFailure" value="false"/> <!--當連接池用完時客戶端調用getConnection()後等待獲取新連接的時間,超時後將拋出 SQLException,如設爲0則無限期等待。單位毫秒。Default: 0 --> <property name="checkoutTimeout" value="0"/> <!--通過實現ConnectionTester或QueryConnectionTester的類來測試連接。類名需制定全路徑。 Default: com.mchange.v2.c3p0.impl.DefaultConnectionTester--> <!--<property name="connectionTesterClassName" value="cn.bb.entity.Test"></property>--> <!--指定c3p0 libraries的路徑,如果(通常都是這樣)在本地即可獲得那麼無需設置,默認null即可 Default: null--> <property name="factoryClassLocation" value="null"/> <!--Strongly disrecommended. Setting this to true may lead to subtle and bizarre bugs. (文檔原文)作者強烈建議不使用的一個屬性--> <property name="forceIgnoreUnresolvedTransactions" value="false"/> <!--每60秒檢查所有連接池中的空閒連接。Default: 0 --> <property name="idleConnectionTestPeriod" value="60"/> <!--初始化時獲取三個連接,取值應在minPoolSize與maxPoolSize之間。Default: 3 --> <property name="initialPoolSize" value="3"/> <!--最大空閒時間,60秒內未使用則連接被丟棄。若爲0則永不丟棄。Default: 0 --> <property name="maxIdleTime" value="60"/> <!--連接池中保留的最大連接數。Default: 15 --> <property name="maxPoolSize" value="15"/> <!--JDBC的標準參數,用以控制數據源內加載的PreparedStatements數量。但由於預緩存的statements 屬於單個connection而不是整個連接池。所以設置這個參數需要考慮到多方面的因素。 如果maxStatements與maxStatementsPerConnection均爲0,則緩存被關閉。Default: 0--> <property name="maxStatements" value="100"/> <!--maxStatementsPerConnection定義了連接池內單個連接所擁有的最大緩存statements數。Default: 0 --> <property name="maxStatementsPerConnection" value="5"/> <!--c3p0是異步操作的,緩慢的JDBC操作通過幫助進程完成。擴展這些操作可以有效的提升性能 通過多線程實現多個操作同時被執行。Default: 3--> <property name="numHelperThreads" value="3"/> <property name="password" value="postgres"/> <property name="user" value="postgres"/> <!--定義所有連接測試都執行的測試語句。在使用連接測試的情況下這個一顯著提高測試速度。注意: 測試的表必須在初始數據源的時候就存在。Default: null--> <!--<property name="preferredTestQuery" value="select id from test where id = 1"></property>--> <!--用戶修改系統配置參數執行前最多等待300秒。Default: 300 --> <property name="propertyCycle" value="300"/> <!--因性能消耗大請只在需要的時候使用它。如果設爲true那麼在每個connection提交的 時候都將校驗其有效性。建議使用idleConnectionTestPeriod或automaticTestTable 等方法來提升連接測試的性能。Default: false --> <property name="testConnectionOnCheckout" value="false"/> <!--如果設爲true那麼在取得連接的同時將校驗連接的有效性。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已經不推薦使用--> <!--<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"/>
這是描述是掃描Entity包的類,也就是我們所說的domain類,orm框架中戶數據對於的類
<!--annotatedPackages 使用annotatedPackages 不生效,使用packagesToScan生效-->
<property name="packagesToScan">
<list>
<value>cn.bb.entity</value>
</list>
</property>
這裏描述的是採用packagesToScan參數掃描entity,生成數據表。
2:DAO的配置
爲了避免框架的侵入,spring不推薦使用hibernateTemplate作爲數據訪問的入庫,而是使用hibernate框架自身的SessionFactory,該SessionFactory在上面dbContext.xml已經配置對應的類是:org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean(具體怎麼注入有待研究)。這樣在DAO的java代碼中只有hibernate框架的代碼,而沒有spring框架的代碼,這樣就避免了框架的侵入,職責的單一原則。
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); } }
上面代碼中可以發現數據庫操作獲取hibernatesession的操作都是採用this.sessionFactory.getCurrentSession(),這是Spring官方推薦的,可以提高性能和控制事務。
3:事務控制
採用以上DAO的編碼方式必須引入事務控制,因爲this.sessionFactory.getCurrentSession()是在當前綁定事務中獲取session,當事務不存在時就會保存,如:
org.hibernate.HibernateException: No Hibernate Session bound to thread, and configuration does not allow creation of non-transactional one here
採用aop配置事務方式爲: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>
這樣就對GoodService進行了事務控制
GoodService的代碼如下:
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"); //不會回滾 throw new RuntimeException("aa"); //會回滾 } }
在測試用,發現在saveGoodBatch拋出 new Exception 不會產生回滾,拋出 RuntimeException時會發生回滾。
4:注意的東西
事務應該控制到service層,在dao和service中不應該捕獲異常,也就是出現try..catch..語句,所有異常都在web層進行處理,這樣可以讓service層的事務進行回滾,從而避免了數據的不一致。
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>