基于注解的AOP配置

Posted 2021-02-28 aitiknowledge

基于注解的AOP配置（一定要要参考上一篇的“基于xml文件的AOP配置”）

• 主要是将上面的xml文件的内容替换掉，以下是xml文件所有内容，环绕通知的内容就是替换四种通知即可

  <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.xsd
          http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd">
      
      <bean id="wordsService" class="com.mypro.service.impl.WordsServiceImpl"></bean>
      
      <bean id="logger" class="com.mypro.service.impl.WordsServiceImpl"></bean>
  <aop:config>
      <aop:aspect id="loggerAdvice" ref="logger">
          <aop:pointcut id="pt1" expression="execution(* com.mypro.service.impl.*.*(..))"></aop:point>
          <aop:before method="beforeInfo" pointcut-ref="pt1"></aop:before>
          <aop:after-returning method="afterReturningInfo" pointcut-ref="pt1"></aop:after-returning>
          <aop:after-throwing method="afterThrowingInfo" pointcut-ref="pt1"></aop:after-throwing>
          <aop:after method="afterInfo" pointcut-ref="pt1"></aop:after>
      </aop:aspect>
  </aop:config>
  </beans>

• 首先我们需要配置我们扫描的包，将xml文件的Bean对象替换成注解，即在我们实现类上方添加注解。在此之前，还需要添加xmlns:context依赖

  <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:context="http://www.springframework.org/schema/context"
         xsi:schemaLocation="
          http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
          http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd
          http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
      <!-- 代替xml文件的两个Bean对象的配置 -->
      <context:component-scan base-package="com.mypro"></context:component-scan>
  </beans>

• 开启Spring支持的AOP配置

  <aop:aspectj-autoproxy></aop:aspectj-autoproxy>

• 修改通知类的代码，注意实现五种通知标签的功能

  package com.mypro.utils;
  ?
  import org.aspectj.lang.ProceedingJoinPoint;
  import org.aspectj.lang.annotation.*;
  import org.springframework.stereotype.Component;
  ?
  /**
   * 用于记录日志的工具类，里面提供公共的代码
   */
  // 代替xml文件的<aop:config><aop:aspect id="loggerAdvice" ref="logger"></aop:aspect></aop:config>
  @Component("logger")
  @Aspect                      
  public class Logger {
      
      // 代替切入点的配置
      @Pointcut("execution(* com.mypro.service.impl.*.*(..))")
      public void pt1(){}
  ?
      @Before("pt1()")
      public void beforeInfo(){
          System.out.println("前置通知");
      }
      @AfterReturning("pt1()")
      public void totalInfo(){
          System.out.println("后置通知");
      }
      @AfterThrowing("pt1()")
      public void expectInfo(){
          System.out.println("异常通知");
      }
      @After("pt1()")
      public void afterInfo(){
          System.out.println("最终通知");
      }
      
      @Around("pt1()")
      public Object aroundInfo(){
          Object rtValue = null;
          try{
              System.out.println("前置通知");
              // 得到方法执行时所需的参数
              Object[] args = pjp.getArgs();
              // 明确调用业务层方法（切入点方法）
              rtValue = pjp.proceed(args);
              System.out.println("后置通知");
              return rtValue;
          }catch(Throwable t){      // 必须是用Throwable捕捉异常
              System.out.println("异常通知");
              throw new RuntimeException(t);
          }finally{
              System.out.println("最终通知");
          }
      }
  ?
  }
  ?