基于@Aspect 注解

基于@Aspect 注解的AOP开发主要需要目标类、切面、配置文件。
调用关系如图：

首先引入jar包：
下载jar
目标类（HelloWorld）：

package com.demo.spring.aop;

public class Helloworld {
    protected String message;//定义String 类型变量

    public String getMessage() {
        return message;
    }

    public void setMessage(String message) {
        this.message = message;
    }

    public void execute(){
        System.out.println("Hello"+getMessage()+"!");
    }

}

切面：

package com.demo.spring.aop;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.annotation.Pointcut;

@Aspect
public class MyAspect {

    /** * 定义切入点函数 */
    @Pointcut("execution(* com.demo.spring.aop.*.execute*(..))")
    void pointcut(){

    }
    /** * 使用@Before声明前置通知 * @param thisJoinPoint */
    @Before("pointcut()")
    public void beforeExecute(JoinPoint thisJoinPoint){
        System.out.println("start to say:");
    }
    /** * 使用@Around 注解声明环绕通知 * @param thisJoinPoint * @return * @throws Throwable */
    @Around("pointcut()")
    public Object userOperate(ProceedingJoinPoint thisJoinPoint) throws Throwable{
        System.out.println("before 之前");
        Object va=thisJoinPoint.proceed();
        System.out.println("after 之前");
        return va;
    }
    /** * 使用@After 注解声明后置通知 * @param thisJoinPoint */
    @After("pointcut()")
    public void afterExecute(JoinPoint thisJoinPoint){
        System.out.print("end!");
    }
}

applicationContext.xml配置文件：

<?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-2.0.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.0.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.0.xsd">
    <bean id="Helloworld" class="com.demo.spring.aop.Helloworld">
        <property name="message">
            <value>World</value>    
        </property>
    </bean>
    <aop:aspectj-autoproxy></aop:aspectj-autoproxy>
    <bean id="myAspect" class="com.demo.spring.aop.MyAspect"></bean>

</beans>

客户端调用：
package com.demo.spring.aop;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.FileSystemXmlApplicationContext;

public class Test {

public static void main(String[] args) {
    ApplicationContext ctx=new FileSystemXmlApplicationContext("WebRoot/WEB-INF/applicationContext.xml");
    Helloworld hello=(Helloworld) ctx.getBean("Helloworld");
    hello.execute();
}

}
这中方式主要是用Spring的注解方式开发AOP，还有一种是通过Schema(xml)的方式

基于Schema(xml)

与@Aspect注解相比不同之处主要在切面类与配置文件上，切面类不再用注解，而是在配置文件中配置增强
切面类：

package com.demo.spring.aop;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Aspect;

/** * 切面类 * @author dandan * */
@Aspect
public class MyAspect {
    /** * 前置通知 * @param thisJoinPoint */
    public void beforeExecute(JoinPoint thisJoinPoint){
        System.out.println("start to say：");
    }
    /** * 环绕通知类 * @param thisJoinPoint * @return * @throws Throwable */
    public Object userOperate(ProceedingJoinPoint thisJoinPoint) throws Throwable{
        return thisJoinPoint.proceed();
    }
    /** * 后置通知类 * @param thisJoinPoint */
    public void  afterExecute(JoinPoint thisJoinPoint){
        System.out.println("end!");
    }
}

配置文件：

<?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-2.0.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.0.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.0.xsd">
    <bean id="HelloWorld" class="com.demo.spring.aop.HelloWorld">
        <property name="message">
            <value>World</value>
        </property>
    </bean>
    <bean id="myAspect" class="com.demo.spring.aop.MyAspect"></bean>
    <aop:config>
        <!-- 定义切面 -->
        <aop:aspect id="aopAspect" ref="myAspect">
            <!-- 定义切点 -->
            <aop:pointcut id="pointcut" expression="execution(* execute(..)) and target(com.demo.spring.aop.HelloWorld)"/>
            <!-- 定义通知 -->
            <aop:before pointcut-ref="pointcut" method="beforeExecute"/>
            <aop:around pointcut-ref="pointcut" method="userOperate"/>
            <aop:after pointcut-ref="pointcut" method="afterExecute"/>
        </aop:aspect>
    </aop:config>
</beans>