一个简单的Spring的AOP例子

经过这段日子的学习和使用Spring,慢慢地体会到Spring的优妙之处，正在深入地吸收Spring的精华，呵呵。现在写的这个只是个简单AOP例子,包括前置通知，后置通知,环绕通知,和目标对象。写这个例子的主要目标只是想让想学AOP的能更快地入门，了解一下如何去配置AOP里面的东东。

目标对象的接口:IStudent.java

package com.dragon.study;
public interface IStudent {
public void addStudent(String name);
}

目标类:StudentImpl.java

package com.dragon.study.Impl;

import com.dragon.study.IStudent;

public class StudentImpl implements IStudent {

public void addStudent(String name) {

System.out.println( " 欢迎 " + name + " 你加入Spring家庭! " );

}

}

前置通知:BeforeAdvice.java

package com.dragon.Advice;
import java.lang.reflect.Method;
import org.springframework.aop.MethodBeforeAdvice;
public class BeforeAdvice implements MethodBeforeAdvice{
public void before(Method method,Object[] args, Object target) throws Throwable {
System.out.println( " 这是BeforeAdvice类的before方法. " );
}
}

后置通知:AfterAdvice.java

package com.dragon.Advice;
import java.lang.reflect.Method;


import org.springframework.aop.AfterReturningAdvice;
public class AfterAdvice implements AfterReturningAdvice{
public void afterReturning(Object returnValue ,Method method, Object[] args,Object target) throws Throwable{
System.out.println("这是AfterAdvice类的afterReturning方法.");
}
}

环绕通知:CompareInterceptor.java

package com.dragon.Advice;
import org.aopalliance.intercept.MethodInterceptor;
import org.aopalliance.intercept.MethodInvocation;
public class CompareInterceptor implements MethodInterceptor{
public Object invoke(MethodInvocation invocation) throws Throwable{
Object result = null;
String stu_name = invocation.getArguments()[0].toString();
if ( stu_name.equals("dragon")){
//如果学生是dragon时,执行目标方法,
result= invocation.proceed();
} else{
System.out.println("此学生是"+stu_name+"而不是dragon,不批准其加入.");
}
return result;
}
}

配置文件applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">


<beans>


<bean id="beforeAdvice" class="com.dragon.Advice.BeforeAdvice"></bean>


<bean id="afterAdvice" class="com.dragon.Advice.AfterAdvice"></bean>


<bean id="compareInterceptor" class="com.dragon.Advice.CompareInterceptor"></bean>


<bean id="studenttarget" class="com.dragon.study.Impl.StudentImpl"></bean>




<bean id="student" class="org.springframework.aop.framework.ProxyFactoryBean">


<property name="proxyInterfaces">


<value>com.dragon.study.IStudent</value>


</property>


<property name="interceptorNames">


<list>


<value>beforeAdvice</value>


<value>afterAdvice</value>


<value>compareInterceptor</value>


</list>


</property>


<property name="target">


<ref bean="studenttarget"/>


</property>
</bean>
</beans>

现在开始写测试类,Test.java

package com;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.FileSystemXmlApplicationContext;
import com.dragon.study.IStudent;
public class Test {
public static void main(String[] args) {
// TODO Auto-generated method stub
ApplicationContext ctx = new FileSystemXmlApplicationContext("/com/dragon/applicationContext.xml");
IStudent person = (IStudent)ctx.getBean("student");
person.addStudent("dragon");
// person.addStudent("javadragon");
}

}