package com.rzyc.advice;

import com.github.pagehelper.PageHelper;
import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.annotation.Pointcut;
import org.springframework.stereotype.Component;

import java.lang.reflect.Field;

/**
 * @Author jilin
 * @Date 2021/11/09 11:57
 * 分页aop
 * 注解写在mapper上，aop代理方式需为jdk代理，cglib代理无法aop mapper
 **/
@Aspect
@Component
public class PageAspect {
    @Pointcut("@annotation(com.rzyc.advice.PageOperation)execution(* com.rzyc..*.*(..))")
    public void page() {}

    @Before("page()")
    public void pageOperation(JoinPoint joinPoint) throws IllegalAccessException, NoSuchFieldException {
        Object[] args = joinPoint.getArgs();
        Class clazz = args[0].getClass();
        Field page = clazz.getDeclaredField("page");
        page.setAccessible(true);
        Field pageSize = clazz.getDeclaredField("pageSize");
        pageSize.setAccessible(true);
        PageHelper.startPage((Integer) page.get(args[0]),(Integer) pageSize.get(args[0]));
    }
}