Spring知识点（使用注解实现5种通知）

1. 组件的注解(使用这个注解可以向容器注册bean)

   • repository
   • service
   • controller
   • component

2. 导入jar
   

   建立一个dao包

package dao;

public interface SayDao {
  String SayAWord();
}

建立daoimpl包

package daoimpl;

import org.springframework.stereotype.Repository;

import dao.SayDao;
//往applicationContent注册bean
@Repository("say")
public class Say implements SayDao {
   
	public String SayAWord() {
		
		return "你好aop";
	}
}

建立Service包

package service;

import org.springframework.stereotype.Service;


public interface PeopleDao {
	
  String PeopleSay();
	
}

建立ServiceImpl包

package serviceimpl;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import dao.SayDao;
import daoimpl.Say;
import service.PeopleDao;

@Service("people")
public class People implements PeopleDao {
   
   @Autowired
   private SayDao say;
   
   public String PeopleSay() {
	   return this.say.SayAWord();
   }

public SayDao getSay() {
	return say;
}

public void setSay(Say say) {
	this.say = say;
}
   
   
}

建立测试类：

package test;

import java.lang.reflect.Proxy;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import service.PeopleDao;
import serviceimpl.People;

public class test {
public static void main(String[] args) {
	ApplicationContext applicationContext=new ClassPathXmlApplicationContext("applicationContent.xml");
	PeopleDao people=(PeopleDao)applicationContext.getBean("people");
	System.out.println(people.PeopleSay());
	
	
	
}
}

注意看关键的一句

//使用这用写法的aop会使用Jdk原生的动态代理
PeopleDao people=(PeopleDao)applicationContext.getBean("people");

//产生一个代理类
	PeopleDao people1=(PeopleDao)Proxy.newProxyInstance(test.class.getClassLoader(), new Class[] {PeopleDao.class} ,new InvocationHandler() {

		@Override
		public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
			   
			System.out.println("死");
			return null;
		}
		
	});
	
	
people1.PeopleSay();

另外一种写法

//使用这用写法的aop会使用CGLIB代理
People people=(People)applicationContext.getBean("people");

关于@Asprect注解的使用

package aop;



import java.util.Arrays;

import org.apache.log4j.Logger;
import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.AfterReturning;
import org.aspectj.lang.annotation.AfterThrowing;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.springframework.stereotype.Component;
//声明是切面
@Aspect
public class UseServiceLog {
  private Logger logger=Logger.getLogger(UseServiceLog.class);
  
  //织入前置通知
  @Before("execution(public String PeopleSay())")
  public void before(JoinPoint p) {
	 logger.info("-----调用了"+p.getTarget()+"的"+p.getSignature().getName()+"方法"); 
	 System.out.println("前置");
  }
  
 /* @After("execution(public String PeopleSay())") 
  public void after(JoinPoint p) {
	  logger.info("-----调用了"+p.getTarget()+"的"+p.getSignature().getName()+"方法");
	  System.out.println("后置");
  }
  
  
  @AfterReturning("execution(public String PeopleSay())") 
  public void afterreturn(JoinPoint p,Object result) {
	  logger.info("-----调用了"+p.getTarget()+"的"+p.getSignature().getName()+"方法"
			  +result.toString()
			  );
	  System.out.println("返回通知");
  }
  
  @AfterThrowing("execution(public String PeopleSay())") 
  //添加异常通知方法
  public void afterthrowing(JoinPoint p,RuntimeException exception) {
	  logger.info("-----调用了"+p.getTarget()+"的"+p.getSignature().getName()+"方法"
			  +exception.toString()
			  );
	  System.out.println("异常通知");
  }
  
  @Around("execution(public String PeopleSay())") 
  //环绕通知
  public Object around(ProceedingJoinPoint pjd) {

         Object result = null;//返回值
         String methodName = pjd.getSignature().getName();//得到方法名
         
         try {
             //前置通知
             System.out.println("The method " + methodName + " begins with " + Arrays.asList(pjd.getArgs()));
             result = pjd.proceed();//执行方法 //返回通知
             System.out.println("The method " + methodName + " ends with " + result);
         } catch (Throwable e) {
             //异常通知
             System.out.println("The method " + methodName + " occurs exception:" + e);
             throw new RuntimeException(e);
         }
         //后置通知
         System.out.println("The method " + methodName + " ends");
         return result;
  }*/
  
  

  
  
}