第一步：添加依賴

        <dependency>  
            <groupId>org.springframework.boot</groupId>  
            <artifactId>spring-boot-starter-aop</artifactId>  
        </dependency>  

第二步：定義一個切面類

package com.example.demo.aop;


import java.lang.reflect.Method;
import java.util.Arrays;

 
import javax.servlet.http.HttpServletRequest;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.*;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;
 
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;

import static com.sun.xml.internal.ws.dump.LoggingDumpTube.Position.Before;

@Component
@Aspect // 將一個java類定義為切面類
@Order(-1)//如果有多個aop,這裏可以定義優先級,越小級別越高
public class
 
 LogDemo {
    private static final Logger LOG = LoggerFactory.getLogger(LogDemo.class);

    @Pointcut("execution(* com.example.demo.test.TestController.test(..))")//兩個..代表所有子目錄，最後括號裏的兩個..代表所有參數
    public void logPointCut() {
    }

    @Before("logPointCut()")
    public void doBefore(JoinPoint joinPoint) throws Throwable {
        // 接收到請求，記錄請求內容
        ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
        HttpServletRequest request = attributes.getRequest();
        System.out.println("before");

    }

    @After(value = "logPointCut()")
    public void after(JoinPoint joinPoint) {
        System.out.println("after");
    }


    @AfterReturning(returning = "ret", pointcut = "logPointCut()")// returning的值和doAfterReturning的參數名一致
    public void doAfterReturning(Object ret) throws Throwable {
        System.out.println("AfterReturning");
    }

    @Around("logPointCut()")
    public void doAround(ProceedingJoinPoint pjp) throws Throwable {
        System.out.println("around1");
        Object ob = pjp.proceed();//環繞通知的進程方法不能省略，否則可能導致無法執行
        System.out.println("around2");
    }
}

註意：

如果同一個 切面類，定義了定義了兩個 @Before，那麽這兩個 @Before的執行順序是無法確定的

對於@Around，不管它有沒有返回值，但是必須要方法內部，調用一下 pjp.proceed();否則，Controller 中的接口將沒有機會被執行，從而也導致了 @Before不會被觸發

測試的controller如下：

package com.example.demo.test;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;


@Controller
public class TestController {

    @RequestMapping(value = "test",method = RequestMethod.GET)
    @ResponseBody
    public String test(String name){
        System.out.println("============method");
        return name;
    }
}

配置完成，看看效果，輸出如下：

around1
before
============method
around2
after
AfterReturning

可以看到，切面方法的執行如下：

around-->before-->method-->around-->after-->AfterReturning

如果配置了@AfterThrowing,當有異常時，執行如下：

around-->before-->method-->around-->after-->AfterThrowing

springboot aop使用介紹