spring切面编程

 xml配置实现

先写三个类

public String amethod(String s) {
  System.out.println("This is AAAAAAAAAAAAAAAA");
  return "This is A return :"+s;
 }
public class B {
    public void bmethod() {
        System.out.println("This is BBBBBBBBBBBBBBBBBBBBB ");
    }
}
//这个类实现了spring里的接口，在配置文件中配置advisor的bean

public class C implements AfterReturningAdvice{

 @Override
 public void afterReturning(Object returnValue, Method method, Object[] args, Object target) throws Throwable {

  System.out.println("This is returnValue:"+returnValue.toString());
  System.out.println("This is method:"+method.getName());
  for (Object arg : args) {
   System.out.println("This is args:"+arg.toString());
  }
  System.out.println("This is target:"+target);
 }
}

spring配置文件内容

<bean id="a" class="com.hehe.aop.A" />
 <bean id="b" class="com.hehe.aop.B" />

 <bean id="c" class="com.hehe.aop.C" />
 <aop:config>
  <aop:pointcut id="p" expression="execution(* com.hehe.aop.A.*(..))" />

  <!-- advicor 要实现spring里的接口 -->
  <aop:advisor advice-ref="c" pointcut-ref="p" />

  <!-- 切面，普通类，b的bmethod方法切入定义好的切点位置 -->
  <aop:aspect ref="b">
   <!-- 切点可以写表达式，也可以引用定义好的，下面两种效果一样 -->
   <!-- <aop:before method="bmethod" pointcut="execution(* com.hehe.aop.A.*(..))" /> -->
   <aop:before method="bmethod" pointcut-ref="p" />
  </aop:aspect>
 </aop:config>

写个执行方法

public static void main(String[] args) {
  ApplicationContext context = new ClassPathXmlApplicationContext("spring-aop.xml");
  A a =  (A) context.getBean("a");
  a.amethod("Hello world");
 }

执行结果：

This is BBBBBBBBBBBBBBBBBBBBB        //切点类之前执行
This is AAAAAAAAAAAAAAAA                     //切点类
This is returnValue:This is A return :Hello world //下面语句是切点类之后执行结果
This is method:amethod
This is args:Hello world
This is target:com.hehe.aop.A@7fa98a66

注解实现

先写俩类

public class A {
    public String amethod(String s) {
        System.out.println("This is AAAAAAAAAAAAAAAA");
        return "This is A return :"+s;
    }
}

@Component
@Aspect
public class D {

    @AfterReturning(value = "execution(* com.hehe.aop.A.*(..))",returning="returnValue")
    public void dmethod(JoinPoint j,Object returnValue) {
        System.out.println(returnValue.toString());
        String name = j.getSignature().getName();
        System.out.println(name);
    }
}

//好几个joinpoint，用这个：import org.aspectj.lang.JoinPoint;

配置文件

<context:component-scan base-package="com.hehe.aop" />
    <aop:aspectj-autoproxy/>//这个必须要有，没有还不报错。
    <bean id="a" class="com.hehe.aop.A" />

测试类

public class Main {
    public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("spring-aop.xml");
        A a =  (A) context.getBean("a");
        a.amethod("Hello world");
    }
}

测试结果

This is AAAAAAAAAAAAAAAA
This is A return :Hello world
amethod