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目录
环绕通知必须依赖形参ProceedingJoinPoint才能实现对原始方法的调用,进而实现原始方法调用前后同时添加通知
通知中如果未使用ProceedingJoinPoint对原始方法进行调用将跳过原始方法的执行
对原始方法的调用可以不接收返回值,通知方法设置成void即可,如果接收返回值,最好设定为Object类型
原始方法的返回值如果是void类型,通知方法的返回值类型可以设置成void,也可以设置成Object
由于无法预知原始方法运行后是否会抛出异常,因此环绕通知方法必须要处理Throwable异常
介绍完这么多种通知类型,具体该选哪一种呢?
我们可以通过一些案例加深下对通知类型的学习。
- @Around("pt2()")
- public Object aroundSelect(ProceedingJoinPoint pjp) throws Throwable {
- System.out.println("around before advice ...");
- //表示对原始操作的调用
- Object ret = pjp.proceed();
- System.out.println("around after advice ...");
- return ret;
- }
案例设定:测算接口执行效率,但是这个案例稍微复杂了点,我们对其进行简化。
简化设定:在方法执行前输出当前系统时间。
对于SpringAOP的开发有两种方式,XML 和 ==注解==,我们使用哪个呢?
因为现在注解使用的比较多,所以本次课程就采用注解完成AOP的开发。
总结需求为:使用SpringAOP的注解方式完成在方法执行的前打印出当前系统时间。
需求明确后,具体该如何实现,都有哪些步骤,我们先来分析下:
1.导入坐标(pom.xml)
2.制作连接点(原始操作,Dao接口与实现类)
3.制作共性功能(通知类与通知)
4.定义切入点
5.绑定切入点与通知关系(切面)
- <?xml version="1.0" encoding="UTF-8"?>
- <project xmlns="http://maven.apache.org/POM/4.0.0"
- xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
- xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
- <modelVersion>4.0.0</modelVersion>
-
- <groupId>org.example</groupId>
- <artifactId>SpringAop</artifactId>
- <version>1.0-SNAPSHOT</version>
- <dependencies>
- <dependency>
- <groupId>org.springframework</groupId>
- <artifactId>spring-context</artifactId>
- <version>5.2.10.RELEASE</version>
- </dependency>
- <dependency>
- <groupId>org.aspectj</groupId>
- <artifactId>aspectjweaver</artifactId>
- <version>1.9.4</version>
- </dependency>
- <dependency>
- <groupId>org.springframework</groupId>
- <artifactId>spring-test</artifactId>
- <version>5.2.10.RELEASE</version>
- </dependency>
- </dependencies>
-
- <properties>
- <maven.compiler.source>8</maven.compiler.source>
- <maven.compiler.target>8</maven.compiler.target>
- </properties>
-
- </project>
- package com.itheima.dao;
-
- public interface book {
- public void save();
- public void update();
- }
-
-
- package com.itheima.dao.impl;
-
- import com.itheima.dao.book;
- import org.springframework.stereotype.Repository;
-
- @Repository
- public class bookimpl implements book {
- @Override
- public void save() {
- System.out.println("方法1");
- }
-
- @Override
- public void update() {
- System.out.println("方法2");
-
- }
-
- @Override
- public int select() {
- System.out.println("save()方法执行成功!");
- return 100;
- }
-
- }
- package com.itheima.SpringConfig;
-
- import org.springframework.context.annotation.ComponentScan;
- import org.springframework.context.annotation.EnableAspectJAutoProxy;
- import org.springframework.stereotype.Component;
-
- @Component
- @ComponentScan("com.itheima")
- @EnableAspectJAutoProxy
- public class SpringConfig {
- }
- package com.itheima.aop;
-
- import org.aspectj.lang.ProceedingJoinPoint;
- import org.aspectj.lang.annotation.Around;
- import org.aspectj.lang.annotation.Aspect;
- import org.aspectj.lang.annotation.Before;
- import org.aspectj.lang.annotation.Pointcut;
- import org.springframework.stereotype.Component;
-
- @Component
- @Aspect
- public class bookaop {
-
- //绑定连接点
- @Pointcut("execution(int *com.itheima.*.*book.select(..))")
- private void aa(){};
- @Pointcut("execution(void *com.itheima.*.*book.update(..))")
- private void bb(){};
- //绑定切面
- @Before("bb()")
- //创建通知
- public void kk(){
- System.out.println("郭浩康加油");
- }
-
- //@Before("aa()")
- // public void before() {
- // System.out.println("before advice ...");
- // }
- //@After("aa()")
- // public void after() {
- // System.out.println("after advice ...");
- // }
- @Around("aa()")
- public Object around(ProceedingJoinPoint pjp) throws Throwable {
- System.out.println("around before advice ...");
- Object proceed = pjp.proceed();
-
- System.out.println("around after advice ...");
- return proceed;
- }
-
- public void afterReturning() {
- System.out.println("afterReturning advice ...");
- }
-
- public void afterThrowing() {
- System.out.println("afterThrowing advice ...");
- }
- }
- package com.itheima;
-
- import com.itheima.SpringConfig.SpringConfig;
- import com.itheima.dao.book;
- import org.springframework.context.ApplicationContext;
- import org.springframework.context.annotation.AnnotationConfigApplicationContext;
-
- public class APP {
- public static void main(String[] args) {
- ApplicationContext ctx=new AnnotationConfigApplicationContext(SpringConfig.class);
- book book = ctx.getBean(book.class);
- book.save();
-
- }
- }
- package com.itheima;
-
- import com.itheima.SpringConfig.SpringConfig;
- import com.itheima.dao.book;
- 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(classes = SpringConfig.class)
- public class test {
- @Autowired
- private book bk;
-
- @Test
- public void testsave(){
- bk.update();
- }
- @Test
- public void testselect(){
- int select = bk.select();
- System.out.println(select);
- }
- }
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