Spring AOP Schema aop:config、tx:advice

Spring AOP Schema  aop:config、tx:advice

一、      利用aop:config标签实现AOP

首先看个例子，如下

接口代码：

package com.lei.demo.aop.schema;public interface IHello {    public void sayHello();}

 

接口实现：

package com.lei.demo.aop.schema;public class HelloService implements IHello {    public void sayHello() {        System.out.println("-----Hello World!-----");    }}

接下来我们要实现AOP，即调用sayHello方法时切入通知。

1.      第一种方法aop:config中配置aop:pointcut和aop:aspect

定义一个切面支持类HelloAspect.java

package com.lei.demo.aop.schema;/* * 切面支持类 */public class HelloAspect {    //前置通知      public void beforeAdvice() {          System.out.println("===========before advice");      }        //后置最终通知      public void afterFinallyAdvice() {          System.out.println("===========after finally advice");    }}

 

Xml配置：Spring-AOP-Schema.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"          xsi:schemaLocation="             http://www.springframework.org/schema/beans             http://www.springframework.org/schema/beans/spring-beans-3.2.xsd             http://www.springframework.org/schema/aop             http://www.springframework.org/schema/aop/spring-aop-3.2.xsd">               <!-- 目标类 -->    <bean id="helloService" class="com.lei.demo.aop.schema.HelloService" />        <bean id="helloAspect" class="com.lei.demo.aop.schema.HelloAspect" />            <!-- 配置切面 -->    <!-- aop:advisor，是有顺序的，必须放在aop:pointcut之后 -->    <aop:config>        <aop:pointcut id="helloPointcut" expression="execution(* com.lei.demo.aop.schema..*.*(..))" />                <aop:aspect ref="helloAspect">            <!—以下使用了两种方法定义切入点  pointcut-ref和pointcut-->            <aop:before pointcut-ref="helloPointcut" method="beforeAdvice" />            <aop:after pointcut="execution(* com.lei.demo.aop.schema..*.*(..))" method="afterFinallyAdvice" />        </aop:aspect>                    </aop:config></beans>

以上配置中method="beforeAdvice"、method="afterFinallyAdvice"对应helloAspect中的方法

 

测试，App.java

package com.lei.demo.aop.schema;import org.springframework.context.ApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext;public class App {    private static ApplicationContext ctx;    public static void main(String[] args) {                ctx = new ClassPathXmlApplicationContext("Spring-AOP-Schema.xml");                IHello helloService = ctx.getBean("helloService",IHello.class);                helloService.sayHello();    }}

 

运行App.java，结果如下：

===========before advice

-----Hello World!-----

===========after finally advice

 

2.      第二种方法aop:config中配置aop:pointcut和aop:advisor

实现org.aopalliance.intercept.MethodInvocation接口，

HelloAroundAdvice.java如下：

package com.lei.demo.aop.schema;import java.lang.reflect.Method;import org.aopalliance.intercept.MethodInterceptor;import org.aopalliance.intercept.MethodInvocation;public class HelloAroundAdvice implements MethodInterceptor {    public Object invoke(MethodInvocation arg0) throws Throwable {        System.out.println("++++++before advice");        arg0.proceed();        System.out.println("++++++after advice");                return null;    }}

 

Xml配置：Spring-AOP-Schema.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"          xsi:schemaLocation="             http://www.springframework.org/schema/beans             http://www.springframework.org/schema/beans/spring-beans-3.2.xsd             http://www.springframework.org/schema/aop             http://www.springframework.org/schema/aop/spring-aop-3.2.xsd">               <!-- 目标类 -->    <bean id="helloService" class="com.lei.demo.aop.schema.HelloService" />        <bean id="helloAspect" class="com.lei.demo.aop.schema.HelloAspect" />        <bean id="helloArroundAdvice" class="com.lei.demo.aop.schema.HelloAroundAdvice" />        <!-- 配置切面 -->    <aop:config>        <aop:pointcut id="helloPointcut" expression="execution(* com.lei.demo.aop.schema..*.*(..))" />        <aop:advisor advice-ref="helloArroundAdvice" pointcut-ref="helloPointcut"/>            </aop:config></beans>

 

仍然运行App.java，结果如下：

++++++before advice

-----Hello World!-----

++++++after advice

 

 

二、      AOP中加入事务，引入tx:advice

集成Hibernate时，需要引入事务，以下配置引用Spring 4.0.3和Hibernate 4.3.5

Spring-hibernate.xml如下：

<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http://www.springframework.org/schema/beans"    xmlns:context="http://www.springframework.org/schema/context"    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"    xmlns:tx="http://www.springframework.org/schema/tx"    xmlns:aop="http://www.springframework.org/schema/aop"    xsi:schemaLocation="        http://www.springframework.org/schema/beans             http://www.springframework.org/schema/beans/spring-beans-4.0.xsd        http://www.springframework.org/schema/context        http://www.springframework.org/schema/context/spring-context-4.0.xsd        http://www.springframework.org/schema/aop        http://www.springframework.org/schema/aop/spring-aop-4.0.xsd        http://www.springframework.org/schema/tx        http://www.springframework.org/schema/tx/spring-tx-4.0.xsd        ">    <!-- Hibernate4 -->    <!-- 加载资源文件  其中包含变量信息，必须在Spring配置文件的最前面加载，即第一个加载-->    <context:property-placeholder location="classpath:persistence-mysql.properties" />        <bean id="sessionFactory"         class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">        <property name="dataSource" ref="dataSource" />        <property name="packagesToScan">            <list>                <!-- 可以加多个包 -->                <value>com.lei.demo.entity</value>            </list>        </property>        <property name="hibernateProperties">            <props>                <prop key="hibernate.hbm2ddl.auto">${hibernate.hbm2ddl.auto}</prop>                <prop key="hibernate.dialect">${hibernate.dialect}</prop>                <prop key="hibernate.show_sql">${hibernate.show_sql}</prop>            </props>        </property>    </bean>        <!-- 数据库映射 -->    <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">      <property name="driverClassName" value="${jdbc.driverClassName}" />      <property name="url" value="${jdbc.url}" />      <property name="username" value="${jdbc.user}" />      <property name="password" value="${jdbc.pass}" />   </bean>       <!-- 配置Hibernate事务管理器 -->    <bean id="transactionManager"        class="org.springframework.orm.hibernate4.HibernateTransactionManager">      <property name="sessionFactory" ref="sessionFactory" />   </bean>      <!-- 配置事务异常封装 -->   <bean id="persistenceExceptionTranslationPostProcessor"        class="org.springframework.dao.annotation.PersistenceExceptionTranslationPostProcessor" />      <!--  声明式容器事务管理 ,transaction-manager指定事务管理器为transactionManager-->    <tx:advice id="txAdvice" transaction-manager="transactionManager">        <tx:attributes>            <tx:method name="add*" propagation="REQUIRED" />            <tx:method name="get*" propagation="REQUIRED" />            <tx:method name="*" read-only="true" />        </tx:attributes>    </tx:advice>        <aop:config expose-proxy="true">        <!-- 只对业务逻辑层实施事务 -->        <aop:pointcut id="txPointcut" expression="execution(* com.lei.demo.service..*.*(..))" />        <!-- Advisor定义，切入点和通知分别为txPointcut、txAdvice -->        <aop:advisor pointcut-ref="txPointcut" advice-ref="txAdvice"/>            </aop:config>    </beans>

 

重点看一下tx:advice的配置

<tx:advice id="txAdvice" transaction-manager="transactionManager">    <tx:attributes>        <tx:method name="add*" propagation="REQUIRED" />        <tx:method name="get*" propagation="REQUIRED" />        <tx:method name="*" read-only="true" />    </tx:attributes></tx:advice>

意思是说，这个事务advice的管理者为transactionManager，而这个advice中规定了匹配add*、get*方法的传输方式为required，也就是说没有sessionFactory的时候会自动建立，有的时候就不会建立了。当然这只是规定了一个advice，你还需要指定一个aop:pointcut去引用它，例如下边的aop:config配置节。这样，这个advice就被织入到txPointcut这个pointcut上了。