Spring AOP之Advice
前置通知:即代码被执行之前被调用
后置通知:即代码执行之后进行调用
环绕通知:即代码执行前后进行调用
这两种方式的实现方式用到了动态代理的思想来完成的,
总结不想说废话:
首先是Spring1.x对Advice的支持:
public interface IHello {
public void sayHello1() ;
public void sayHello2() ;
public void sayHello3() ;
public void sayHello4() ;
}
然后就是类的实现:
package com.spring.test;
public class Hello implements IHello{
public void sayHello1() {
System.out.println("111111111111");
}
public void sayHello2() {
System.out.println("222222222222");
}
public void sayHello3() {
System.out.println("333333333333");
}
public void sayHello4() {
System.out.println("444444444444");
}
}
然后是负责前置通知的类,要实现MethodBeforeAdvice接口:
public class AdviceBeforeHello implements MethodBeforeAdvice {
@Override
public void before(Method arg0, Object[] arg1, Object arg2)
throws Throwable {
System.out.println("验证用户。。。。");
}
}
然后是负责后置通知的类,要实现AfterReturningAdvice接口:
public class AdviceAfterHello implements AfterReturningAdvice{
@Override
public void afterReturning(Object arg0, Method arg1, Object[] arg2,
Object arg3) throws Throwable {
System.out.println("方法执行完毕");
}
}
配置项: <bean id="beforeHello" class="com.spring.advice.AdviceBeforeHello" /> <bean id="afterHello" class="com.spring.advice.AdviceAfterHello"></bean> <bean id="hello" class="com.spring.test.Hello"></bean> <!-- 注册代理类 --> <bean id="proxy" class="org.springframework.aop.framework.ProxyFactoryBean"> <property name="proxyInterfaces"> <value>com.spring.test.IHello</value> </property> <!-- 目标对象,即Hello对象 --> <property name="target" ref="hello"></property> <!-- 应用的前置通知,拦截器名称 --> <property name="interceptorNames"> <list> <value>beforeHello</value> <value>afterHello</value> </list> </property> </bean>
测试方法:
ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");
IHello hello = (IHello) context.getBean("proxy");
hello.sayHello1();
hello.sayHello2();
hello.sayHello3();
hello.sayHello4();
结果:
下面是环绕通知:
public class AdviceAroundHello implements MethodInterceptor{
@Override
public Object invoke(MethodInvocation arg0) throws Throwable {
Object object=null;
System.out.println("验证用户");
try {
object=arg0.proceed();
} finally{
System.out.println("方法执行完毕");
}
return object;
}
}
然后配置beans.xml:
<bean id="aroundHello" class="com.spring.advice.AdviceAroundHello"></bean> <bean id="hello" class="com.spring.test.Hello"></bean> <!-- 注册代理类 --> <bean id="proxy" class="org.springframework.aop.framework.ProxyFactoryBean"> <property name="proxyInterfaces"> <value>com.spring.test.IHello</value> </property> <!-- 目标对象,即Hello对象 --> <property name="target" ref="hello"></property> <!-- 应用的前置通知,拦截器名称 --> <property name="interceptorNames"> <list> <value>aroundHello</value> </list> </property> </bean>
以上是Spring1.x对AOP的支持,,Spring2.x除了支持Spring1.x外,还提供了两种实现AOP的方式:
1.基于XML的配置,使用基于Schema的XML配置来完成AOP而且Advice也不用再实现任何其他特定接口。
2.使用JDK5的注释来完成AOP的实现,只需要一个简单的标签就可以完成AOP的整个过程。
基于XML Schema的前置通知配置如下:
编写通知的逻辑代码:
public class AdviceBeforeHello {
public void beforeHello(){
System.out.println("验证用户。。。。");
}
}
在beans.xml中进行配置:
<?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-2.5.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.5.xsd"> <!-- 注册接口实现类 --> <bean id="hello" class="com.spring.test.Hello"></bean> <aop:config> <!-- --> <aop:pointcut id="beforePointCut" expression="execution(* com.spring.test.IHello.*(..))" /> <aop:aspect id="before" ref="beforeAdvice"> <aop:before method="beforeHello" pointcut-ref="beforePointCut" /> </aop:aspect> </aop:config> <bean id="beforeAdvice" class="com.spring.advice.AdviceBeforeHello"></bean> </beans>
其他不变。。。。
2.基于Annotation的前置通知:
切面类:
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
@Aspect
public class AdviceBeforeHello {
@Before("execution(* com.spring.test.IHello.*(..))")
public void beforeHello(){
System.out.println("验证用户。。。。");
}
}
beans.xml配置:
<?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-2.5.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.5.xsd"> <!-- 注册接口实现类 --> <aop:aspectj-autoproxy></aop:aspectj-autoproxy> <bean id="hello" class="com.spring.test.Hello"></bean> <bean id="beforeAdvice" class="com.spring.advice.AdviceBeforeHello"></bean> </beans>
基于XML和Annotation的后置通知和前置通知类似。下面是基于XML的环绕通知:
import org.aspectj.lang.ProceedingJoinPoint;
public class AdviceAroundHello {
public Object around(ProceedingJoinPoint joinPoint) throws Throwable {
System.out.println("验证用户");
//执行连接点的方法
Object object = joinPoint.proceed();
System.out.println("方法执行完毕");
return object;
}
}
beans.xml配置:
<?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-2.5.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.5.xsd"> <!-- 注册接口实现类 --> <bean id="hello" class="com.spring.test.Hello"></bean> <aop:config> <aop:pointcut id="aroundPointcut" expression="execution(* com.spring.test.IHello.*(..))" /> <aop:aspect id="around" ref="aroundAdvice"> <aop:around method="around" pointcut-ref="aroundPointcut" /> </aop:aspect> </aop:config> <bean id="aroundAdvice" class="com.spring.advice.AdviceAroundHello"></bean> </beans>
其他不变。
-------------------------------------------------------------------------------------------------------------------------------
基于Annotation的环绕通知:
package com.spring.advice;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
@Aspect
public class AdviceAroundHello {
@Around("execution(* com.spring.test.IHello.*(..))")
public Object around(ProceedingJoinPoint joinPoint) throws Throwable {
System.out.println("验证用户");
// 执行连接点的方法
Object object = joinPoint.proceed();
System.out.println("方法执行完毕");
return object;
}
}
beans.xml配置:
<?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-2.5.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.5.xsd"> <!-- 注册接口实现类 --> <aop:aspectj-autoproxy></aop:aspectj-autoproxy> <bean id="hello" class="com.spring.test.Hello"></bean> <bean id="aroundAdvice" class="com.spring.advice.AdviceAroundHello"></bean> </beans>
完成!!