Spring 註解&XML 實現 AOP（面向切面編程）、Spring 純註解實現 AOP

一、Spring 註解&XML 實現 AOP

第一步：新建持久層（dao）接口以及實現類

package cn.lemon.dao;

public interface IAccountDao {
    void in(Float money);

    void out(Float money);
}

package cn.lemon.dao.impl;

import cn.lemon.dao.IAccountDao;
import org.springframework.stereotype.Repository;

@Repository
public class AccountDaoImpl implements IAccountDao {
    @Override
    public void in(Float money) {
        System.out.println("成功轉入" + money + "元錢");
    }

    @Override
    public void out(Float money) {
        System.out.println("成功轉出" + money + "元錢");
    }
}

第二步：新建業務層（service）接口以及實現類

package cn.lemon.service;

public interface IAccountServcie {
    void transfer(Float money);
}

package cn.lemon.service.impl;

import cn.lemon.dao.IAccountDao;
import cn.lemon.service.IAccountServcie;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class AccountServiceImpl implements IAccountServcie {
    @Autowired
    private IAccountDao iAccountDao;

    @Override
    public void transfer(Float money) {
        iAccountDao.in(money);
        iAccountDao.out(money);
    }
}

第三步：新建配置文件 applicationContext.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: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/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">
    <!-- 告知 spring，在創建容器時要掃描的包 -->
    <context:component-scan base-package="cn.lemon"></context:component-scan>
    <!--開啓 Spring 註解對 AOP 的支持
        # proxy-target-class="true" 使用 CGLib 代理
    -->
    <aop:aspectj-autoproxy proxy-target-class="true"></aop:aspectj-autoproxy>
</beans>

第四步：新建註解

package cn.lemon.annotation;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/**
 * @Target說明了Annotation所修飾的對象範圍：Annotation可被用於 packages、types（類、接口、枚舉、Annotation類型）、
 * 類型成員（方法、構造方法、成員變量、枚舉值）、方法參數和本地變量（如循環變量、catch參數）
 * 取值(ElementType.METHOD   用於描述方法
 * RetentionPolicy.RUNTIME：註解不僅被保存到class文件中，jvm加載class文件之後，仍然存在；
 */
@Target({ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
public @interface MyAnnotaiton {

}

第五步：新建增強類 LoggerAdvice.java
第一種寫法

package cn.lemon.advice;

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

@Component
@Aspect//表明當前類是一個切面類（或者說是一個增強類）
public class LoggerAdvice {
    @Before("execution(* cn.lemon.service.impl.*.*(..))")//切入點表達式
    public void before(JoinPoint joinPoint) {
        System.out.println("前置增強，方法爲：" + joinPoint.getSignature().getName());
    }

    @AfterReturning(value = "execution(* cn.lemon.service.impl.*.*(..))", returning = "result")//切入點表達式
    public void afterReturning(JoinPoint joinPoint, Object result) {
        System.out.println("後置增強，方法爲：" + joinPoint.getSignature().getName() + "返回值：" + result);
    }

    @Around("execution(* cn.lemon.service.impl.*.*(..))")//切入點表達式
    public Object around(ProceedingJoinPoint proceedingJoinPoint) throws Throwable {
        System.out.println("環繞前置增強.......");
        Object result = proceedingJoinPoint.proceed();//執行業務方法
        System.out.println("環繞後置增強。。。。。");
        return result;
    }

    @AfterThrowing(value = "execution(* cn.lemon.service.impl.*.*(..))", throwing = "e")//切入點表達式
    public void afterTrowing(JoinPoint joinPoint, Exception e) {
        System.out.println("異常增強，方法名：" + joinPoint.getSignature().getName() + "，異常信息爲：" + e.getMessage());
    }

    @After("execution(* cn.lemon.service.impl.*.*(..))")//切入點表達式
    public void after(JoinPoint joinPoint) {
        System.out.println("最終增強，方法名：" + joinPoint.getSignature().getName());
    }
}

第二種寫法

package cn.lemon.advice;

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

@Component
@Aspect//表明當前類是一個切面類（或者說是一個增強類）
public class LoggerAdvice {
    /**
     * 由於 "execution(* cn.lemon.service.impl.*.*(..))"  切入點表達式在下面多次出現，可以定義一個方法
     */
    @Pointcut("execution(* cn.lemon.service.impl.*.*(..))")
    private void myPointCut() {

    }

    @Before("myPointCut()")//切入點表達式
    public void before(JoinPoint joinPoint) {
        System.out.println("前置增強，方法爲：" + joinPoint.getSignature().getName());
    }

    @AfterReturning(value = "myPointCut()", returning = "result")//切入點表達式
    public void afterReturning(JoinPoint joinPoint, Object result) {
        System.out.println("後置增強，方法爲：" + joinPoint.getSignature().getName() + "返回值：" + result);
    }

    @Around("myPointCut()")//切入點表達式
    public Object around(ProceedingJoinPoint proceedingJoinPoint) throws Throwable {
        System.out.println("環繞前置增強.......");
        Object result = proceedingJoinPoint.proceed();//執行業務方法
        System.out.println("環繞後置增強。。。。。");
        return result;
    }

    @AfterThrowing(value = "myPointCut()", throwing = "e")//切入點表達式
    public void afterTrowing(JoinPoint joinPoint, Exception e) {
        System.out.println("異常增強，方法名：" + joinPoint.getSignature().getName() + "，異常信息爲：" + e.getMessage());
    }

    @After("myPointCut()")//切入點表達式
    public void after(JoinPoint joinPoint) {
        System.out.println("最終增強，方法名：" + joinPoint.getSignature().getName());
    }
}

第六步：新建測試類

package cn.lemon.service.impl;

import cn.lemon.service.IAccountServcie;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = "classpath:/applicationContext.xml")
public class AccountServiceImplTest {
    @Autowired
    private IAccountServcie iAccountServcie;

    @Test
    public void transfer() {
        iAccountServcie.transfer(100f);
    }
}

二、Spring 純註解實現 AOP（修改上面的代碼）

第一步：刪掉配置文件 applicationContext.xml，新建配置類 SpringConfiguration.java

package cn.config;

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

@Configuration//表示是一個配置類
@ComponentScan("cn.lemon")//搜索有註解的包
@EnableAspectJAutoProxy(proxyTargetClass = true)
public class SpringConfiguration {
}

第二步：修改測試類
替換註解@ContextConfiguration(locations = "classpath:/applicationContext.xml")

修改爲：@ContextConfiguration(classes = SpringConfiguration.class)