深入理解Sping——AOP的试水

最新推荐文章于 2025-09-10 22:21:01 发布

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最新推荐文章于 2025-09-10 22:21:01 发布

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文章标签： java python

原文链接：https://my.oschina.net/xjt2014/blog/830729

本文通过定义接口和实现类，结合Spring AOP配置，演示了如何使用AspectJ进行前置和后置增强，展示了如何通过XML配置文件指定切入点和通知，以及不同切面的执行顺序。

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深入理解Sping——AOP的试水

定义接口

public interface HelloWorld {
    void printHelloWorld();

    void doPrint();
}

定义接口的实现

public class HelloWorldImpl1 implements HelloWorld {

    public void printHelloWorld() {
        System.out.println("Enter HelloWorldImpl1.printHelloWorld()");
    }

    public void doPrint() {
        System.out.println("Enter HelloWorldImpl1.doPrint()");
        return;
    }
}

public class HelloWorldImpl2 implements HelloWorld {

    public void printHelloWorld() {
        System.out.println("Enter HelloWorldImpl2.printHelloWorld()");
    }

    public void doPrint() {
        System.out.println("Enter HelloWorldImpl2.doPrint()");
        return;
    }
}

定义Handler

public class LogHandler {

    public void LogBefore() {
        System.out.println("Log before method");
    }

    public void LogAfter() {
        System.out.println("Log after method");
    }
}

public class TimeHandler {

    public void printTime() {
        System.out.println("CurrentTime = " + System.currentTimeMillis());
    }
}

定义XML配置

//spring-context-aop.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-4.2.xsd
        http://www.springframework.org/schema/aop
        http://www.springframework.org/schema/aop/spring-aop-4.2.xsd">

    <bean id="helloWorldImpl1" class="com.melon.spring.aop.helloworld.HelloWorldImpl1"/>
    <bean id="helloWorldImpl2" class="com.melon.spring.aop.helloworld.HelloWorldImpl2"/>
    <bean id="timeHandler" class="com.melon.spring.aop.helloworld.TimeHandler"/>
    <bean id="logHandler" class="com.melon.spring.aop.helloworld.LogHandler"/>

    <!--proxy-target-class 为true，基于类代理；为false，基于接口代理-->
    <aop:config>
        <!--
        （1）aspect里面有一个order属性，order属性的数字就是横切关注点的顺序
        （2）把logHandler定义在timeHandler前面，Spring默认以aspect的定义顺序作为织入顺序
        -->
        <aop:aspect id="time" ref="timeHandler">
            <aop:pointcut id="addAllMethod" expression="execution(* com.melon.spring.aop.helloworld.HelloWorld.*(..))"/>
            <aop:before method="printTime" pointcut-ref="addAllMethod"/>
            <aop:after method="printTime" pointcut-ref="addAllMethod"/>
        </aop:aspect>
        <aop:aspect id="log" ref="logHandler" order="2">
            <aop:pointcut id="printLog" expression="execution(* com.melon.spring.aop.helloworld.HelloWorld.*(..))"/>
            <aop:before method="LogBefore" pointcut-ref="printLog"/>
            <aop:after method="LogAfter" pointcut-ref="printLog"/>
        </aop:aspect>
    </aop:config>
</beans>

定义测试类

@Log4j2
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = {"classpath:spring/spring-context-test.xml"})
@WebAppConfiguration
public class AopTest {
    @Test
    public void testHelloWorld() {

        HelloWorld hw1 = (HelloWorld) SpringContextHolder.getBean("helloWorldImpl1");
        HelloWorld hw2 = (HelloWorld) SpringContextHolder.getBean("helloWorldImpl2");
        hw1.printHelloWorld();
        System.out.println();
        hw1.doPrint();

        System.out.println();
        hw2.printHelloWorld();
        System.out.println();
        hw2.doPrint();
    }
}

执行结果：

Log before method
CurrentTime = 1485690199071
Enter HelloWorldImpl1.printHelloWorld()
CurrentTime = 1485690199079
Log after method

Log before method
CurrentTime = 1485690199079
Enter HelloWorldImpl1.doPrint()
CurrentTime = 1485690199079
Log after method

Log before method
CurrentTime = 1485690199079
Enter HelloWorldImpl2.printHelloWorld()
CurrentTime = 1485690199085
Log after method

Log before method
CurrentTime = 1485690199085
Enter HelloWorldImpl2.doPrint()
CurrentTime = 1485690199085
Log after method

转载于:https://my.oschina.net/xjt2014/blog/830729