Analysis of around enhancement implementation method of spring AOP

This paper describes the implementation method of around enhancement of spring AOP. Share with you for your reference, as follows:

One configuration

<?xml version="1.0" encoding="GBK"?>
<beans xmlns="http://www.springframework.org/schema/beans"
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xmlns:context="http://www.springframework.org/schema/context"
   xmlns:aop="http://www.springframework.org/schema/aop"
   xsi:schemaLocation="http://www.springframework.org/schema/beans
   http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
   http://www.springframework.org/schema/context
   http://www.springframework.org/schema/context/spring-context-4.0.xsd
   http://www.springframework.org/schema/aop
   http://www.springframework.org/schema/aop/spring-aop-4.0.xsd">
   <!-- 指定自动搜索Bean组件、自动搜索切面类 -->
   <context:component-scan
      base-package="org.crazyit.app.service,org.crazyit.app.aspect">
      <context:include-filter type="annotation"
        expression="org.aspectj.lang.annotation.Aspect" />
   </context:component-scan>
   <!-- 启动@AspectJ支持 -->
   <aop:aspectj-autoproxy />
</beans>

Two section class

package org.crazyit.app.aspect;
import org.aspectj.lang.annotation.*;
import org.aspectj.lang.*;
// 定义一个切面
@Aspect
public class TxAspect
{
  // 匹配org.crazyit.app.service.impl包下所有类的、
  // 所有方法的执行作为切入点
  @Around("execution(* org.crazyit.app.service.impl.*.*(..))")
  public Object processTx(ProceedingJoinPoint jp)
    throws java.lang.Throwable
  {
    System.out.println("执行目标方法之前，模拟开始事务...");
    // 获取目标方法原始的调用参数
    Object[] args = jp.getArgs();
    if(args != null && args.length > 1)
    {
      // 修改目标方法的第一个参数
      args[0] = "【增加的前缀】" + args[0];
    }
    // 以改变后的参数去执行目标方法，并保存目标方法执行后的返回值
    Object rvt = jp.proceed(args);
    System.out.println("执行目标方法之后，模拟结束事务...");
    // 如果rvt的类型是Integer，将rvt改为它的平方
    if(rvt != null && rvt instanceof Integer)
      rvt = (Integer)rvt * (Integer)rvt;
    return rvt;
  }
}

Three interfaces

Hello

package org.crazyit.app.service;
public interface Hello {
   // 定义一个简单方法，模拟应用中的业务逻辑方法
   void foo();
   // 定义一个addUser()方法，模拟应用中的添加用户的方法
   int addUser(String name,String pass);
}

World

package org.crazyit.app.service;
public interface World {
   // 定义一个简单方法，模拟应用中的业务逻辑方法
   public void bar();
}

Four implementation classes

HelloImpl

package org.crazyit.app.service.impl;
import org.springframework.stereotype.Component;
import org.crazyit.app.service.*;
@Component("hello")
public class HelloImpl implements Hello {
  // 定义一个简单方法，模拟应用中的业务逻辑方法
  public void foo() {
    System.out.println("执行Hello组件的foo()方法");
  }
  // 定义一个addUser()方法，模拟应用中的添加用户的方法
  public int addUser(String name,String pass) {
    System.out.println("执行Hello组件的addUser添加用户：" + name);
    return 20;
  }
}

WorldImpl

package org.crazyit.app.service.impl;
import org.springframework.stereotype.Component;
import org.crazyit.app.service.*;
@Component("world")
public class WorldImpl implements World {
  // 定义一个简单方法，模拟应用中的业务逻辑方法
  public void bar() {
    System.out.println("执行World组件的bar()方法");
  }
}

Five test categories

package lee;
import org.springframework.context.*;
import org.springframework.context.support.*;
import org.crazyit.app.service.*;
public class BeanTest {
  public static void main(String[] args) {
    // 创建spring容器
    ApplicationContext ctx = new ClassPathXmlApplicationContext("beans.xml");
    Hello hello = ctx.getBean("hello",Hello.class);
    hello.foo();
    hello.addUser("孙悟空","7788");
    World world = ctx.getBean("world",World.class);
    world.bar();
  }
}

Vi. test results

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