語言蒼白無力,我們直接代碼說話
package com.example.demo.aspect;
import org.springframework.stereotype.Component;
@Component
public class AtithmeticCalulator {
public int add(int a,int b){
return a+b;
}
public int sub(int a,int b){
return a-b;
}
public int mul(int a,int b){
return a*b;
}
public int div(int a,int b){
return a/b;
}
}
這是一個類,以方法add為例,當我們想在每一個方面前面添加一個告訴自己方法名和參數的時候,你會怎麼寫?
public int add(int a,int b){
System.out.println("method mane:add 參數["+a+","+b+"]");
return a+b;
}
有沒有感覺很麻煩,如果我四個方法都要用,你就要寫4遍
這個時候AOP派上用場
package com.example.demo.aspect;
import java.util.Arrays;
import java.util.List;
import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.springframework.stereotype.Component;
@Component//将元件加載到ioc容器,必須寫,否則加載不到ioc容器
@Aspect//告訴ioc容器這是一個切面類,裡面有切面方法
public class MyAspect {
//切面表達式public int com.example.demo.aspect.AtithmeticCalulator.*(int,int)
//包com.example.demo.aspect下的AtithmeticCalulator類所是public ,傳回值是int,參數是(int,int)的方法
@Before("execution(public int com.example.demo.aspect.AtithmeticCalulator.*(int,int))")
public void before(JoinPoint joinPoint) {
String name=joinPoint.getSignature().getName();
List<Object> args=Arrays.asList(joinPoint.getArgs());
System.out.println("----the method "+name +" is begin:"+args);
}
@After("execution(public int com.example.demo.aspect.AtithmeticCalulator.*(int,int))")
public void after(JoinPoint joinPoint) {
String name=joinPoint.getSignature().getName();
List<Object> args=Arrays.asList(joinPoint.getArgs());
System.out.println("----the method "+name +" is close:"+args);
}
}