Java面试题 P43：框架篇：Spring-什么是AOP，你们项目中有没有使用AOP

 

 

 

 

 引入切面类依赖

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

 

Log.class

 

import java.lang.annotation.*;
@Target({ElementType.PARAMETER,ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface Log {
    /**
     * 模块名称
     * @return
     */
    public String name() default "";
}

 

 

package com.atguigu.aop;

import com.atguigu.annotation.Log;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.Signature;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Pointcut;
import org.aspectj.lang.reflect.MethodSignature;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.annotation.RequestAttribute;
import org.springframework.web.context.request.RequestAttributes;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;

import javax.servlet.http.HttpServletRequest;
import java.lang.reflect.Method;
import java.util.Date;

@Component
@Aspect //切面类
public class SysAspect {
    /**
     * 切入点
     */
    @Pointcut("@annotation(com.atguigu.annotation.Log)")
    private void pointcut()
    {

    }

    /**
     * 连接点 环绕通知
     * @param joinPoint
     * @return
     * @throws Throwable
     */
    @Around("pointcut()")
    public Object around(ProceedingJoinPoint joinPoint) throws Throwable{
        //获取用户名

        //获取被增强类和方法的信息
        Signature signature=joinPoint.getSignature();
        MethodSignature methodSignature=(MethodSignature) signature;
        //获取被增强的方法对象
        Method method=methodSignature.getMethod();
        //从方法中解析注解
        if(method!=null)
        {
            Log logAnnotation=method.getAnnotation(Log.class);
            System.out.println(logAnnotation.name());
        }
        //方法名
        String name=method.getName();
        System.out.println(name);
        //通过工具类获取Request对象
        RequestAttributes reqa= RequestContextHolder.getRequestAttributes();
        ServletRequestAttributes sra=(ServletRequestAttributes) reqa;
        HttpServletRequest request=sra.getRequest();
        //访问的url
        String url=request.getRequestURI().toString();
        System.out.println(url);
        //请求方式
        String methodName=request.getMethod();
        System.out.println(methodName);

        //登录IP
        String ipAddr="";
        System.out.println(ipAddr);

        System.out.println(new Date());

        return joinPoint.proceed();
    }
} 

结果：