AOP学习

package com.zyp.aspect;

import com.zyp.common.NoLogin;
import lombok.extern.slf4j.Slf4j;
import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.*;
import org.aspectj.lang.reflect.MethodSignature;
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 javax.servlet.http.HttpServletRequest;
import java.lang.reflect.Method;

/**
 * 通知的执行顺序  环绕通知(around)-->前置通知(before)--->
 * 成功返回通知(afterReturning)/失败通知(afterThrowing)--->后置通知(after)--->环绕通知
 * @author syl
 * @description TODO
 * @since 2022/6/23
 */
//定义一个切面
@Aspect
//交给springr容器管理
@Component
//多个切面时,定义切面的执行顺序，数字越小顺序越靠前
@Order(2)
@Slf4j
public class AopTest {

    /**
     * 定义切入点
     */
    @Pointcut("execution(public * com.zyp.controller..*.*(..))")
    public void pointCut(){}


    @Before("pointCut()")
    public void before(){
        log.info("前置通知");
    }

    @After("pointCut()")
    public void after(){
        log.info("后置通知");
    }

    /**
     * ProceedingJoinPoint是环绕通知特有的对象
     * @param joinPoint
     * @return
     * @throws Throwable
     */
    @Around("pointCut()")
    public Object around(ProceedingJoinPoint joinPoint) throws Throwable {
        log.info("环绕通知");
        //获取目标方法参数
        Object[] args = joinPoint.getArgs();
        //获取目标方法的方法签名
        MethodSignature methodSignature = (MethodSignature) joinPoint.getSignature();
        //获取目标方法的方法对象
        Method method = methodSignature.getMethod();
        NoLogin annotation = method.getAnnotation(NoLogin.class);
        if (annotation != null) {
            log.info("免密登录");
        }else{
            //获取请求上下文
            ServletRequestAttributes servletRequestAttributes =
                    (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
            HttpServletRequest request = servletRequestAttributes.getRequest();
            request.getHeader("token");
        }
        //获取目标方法的返回值对象
        Class returnType = methodSignature.getReturnType();
        //执行目标方法并接收返回结果
        Object result = joinPoint.proceed();
        log.info("环绕通知");
        return result;
    }

    @AfterReturning("pointCut()")
    public void afterReturning(JoinPoint joinPoint) throws Throwable {
        log.info("成功返回通知");
    }

    @AfterThrowing("pointCut()")
    public void afterThrowing(JoinPoint joinPoint){
        log.info("异常通知");
    }
}
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