spring-AOP（面向切面编程)-注解方式配置

2018-10-24 08:46:16来源：博客园阅读 ()

项目结构：

增强（切面）类：

package edu.nf.ch12.service.aspect;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.*;
import org.springframework.stereotype.Component;

/**
 * @author wangl
 * @date 2018/10/24
 */
@Aspect //这个注解标识当前的类为一个切面
@Component //标识容器受管的Bean对象
public class UserServiceAspect {

    /**
     * 声明一个切入点,并编写切入点表达式
     */
    @Pointcut("execution(* edu.nf.ch12.service.*.*(..))")
    public void pointcut(){
    }

    /**
     * 前置通知,指定切入点函数
     * 也可在注解中自定义不同的切入点表达式
     * @Before("execution(...)")
     *
     */
    @Before("pointcut()")
    public void before(JoinPoint joinPoint){
        System.out.println("前置通知..."+joinPoint.getArgs()[0]);
    }

    /**
     * 后置通知
     */
    @AfterReturning(value = "pointcut()", returning = "returnVal")
    public void afterReturn(String returnVal){
        System.out.println("后置通知..." + returnVal);
    }

    /**
     * 环绕通知
     */
    @Around("pointcut()")
    public Object around(ProceedingJoinPoint pjp) throws Throwable {
        System.out.println("环绕通知前...");
        Object returnVal = pjp.proceed();
        System.out.println("环绕通知后...");
        return returnVal;
    }

    /**
     * 异常通知
     * 通过pointcut指定切入点
     */
    @AfterThrowing(pointcut = "pointcut()", throwing = "e")
    public void throwableAdvice(Throwable e){
        System.out.println("异常通知..." + e.getMessage());
    }

    /**
     * 最终通知
     */
    @After("pointcut()")
    public void after(){
        System.out.println("最终通知...");
    }

}

配置类AppConfig：

package edu.nf.ch12.service.config;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.EnableAspectJAutoProxy;

/**
 * @author wangl
 * @date 2018/10/24
 */
@ComponentScan("edu.nf.ch12") //启用包扫描
@EnableAspectJAutoProxy //启用AspectJ注解自动配置,proxyTargetClass用于指定是否强制使用cglib代理
public class AppConfig {
}

接口类：

package edu.nf.ch12.service;

/**
 * @author wangl
 * @date 2018/10/24
 */
public interface UserService {

    /**
     * 查询用户
     * @param uid
     * @return
     */
    String getUserNameById(String uid);
}

接口实现类：

package edu.nf.ch12.service.impl;

import edu.nf.ch12.service.UserService;
import org.springframework.stereotype.Service;

/**
 * @author wangl
 * @date 2018/10/24
 */
@Service("userService")
public class UserServiceImpl implements UserService {

    @Override
    public String getUserNameById(String uid) {
        System.out.println("查询用户..."+uid);
        return "user1";
    }
}

程序测试类：

package edu.nf.ch12.test;

import edu.nf.ch12.service.UserService;
import edu.nf.ch12.service.config.AppConfig;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

/**
 * @author wangl
 * @date 2018/10/24
 */
public class UserServiceTest {

    @Test
    public void testGetUser(){
        //ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
        ApplicationContext context = new AnnotationConfigApplicationContext(AppConfig.class);
        UserService service = context.getBean("userService", UserService.class);
        service.getUserNameById("1001");
    }
}

如果半注解半配置文件实现的话， new ClassPathXmlApplicationContext("applicationContext.xml");实例然后再配置一个xml

applicationContext：

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

    <!-- 启用包扫描 -->
    <context:component-scan base-package="edu.nf.ch12"/>
    <!-- 启用AspectJ注解自动配置,proxy-target-class是否强制使用cglib动态代理，true表示强制-->
    <aop:aspectj-autoproxy/>

</beans>