aop（面向切面编程）入门开发

AOP面向切面编程

使用注解

---

MyAdvice

package dang.aop;

import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.annotation.Pointcut;
import org.springframework.stereotype.Component;
//通知类必须配置成Spring管理的bean
@Component
//设置当前类为切面类类
@Aspect
public class MyAdvice {
    //设置切入点，要求配置在方法上方
    @Pointcut("execution(void dang.dao.BookDao.update())")
    private void pt(){}

    //设置在切入点pt()的前面运行当前操作（前置通知）
     @Before("pt()")

    public void method(){
        System.out.println(System.currentTimeMillis());
    }
}

---

SpringConfig

package com.itheima.config;

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

@Configuration
@ComponentScan("com.itheima")
//开启注解开发AOP功能
@EnableAspectJAutoProxy
public class SpringConfig {
}

---

BookDaoImpl

package dang.dao.impl;

import dang.dao.BookDao;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Repository;

@Repository
public class BookDaoImpl implements BookDao {

    public void save() {
        System.out.println(System.currentTimeMillis());
        System.out.println("book dao save ...");
    }

    public void update(){
        System.out.println("book dao update ...");
    }
}

---

App

package dang;

import dang.config.SpringConfig;
import dang.dao.BookDao;
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);
        BookDao bookDao = ctx.getBean(BookDao.class);
        bookDao.update();
//        System.out.println(bookDao);
//        System.out.println(bookDao.getClass());

    }
}