aop记录日志出现的问题

我遇到的问题是 保存方法执行完成之前 又执行了一个findAll(Integer currentPage,Integer pageSize）方法 ，就是下面这个controller方法
由于之前没写 currentPage=1&pageSize=5没写这个参数 ，一直报classes[i]= args[i].getClass();这个地方空指针异常。

也就是下面加粗的地方没写
@RequestMapping(value = “/save.do”,method = RequestMethod.POST)
public String save(Product product){
//productService.save(product);
return “redirect:findAll.do?currentPage=1&pageSize=5”;
}

package com.smx.ssm.controller;

import com.smx.ssm.domain.Product;
import com.smx.ssm.domain.SysLog;
import com.smx.ssm.service.LogAopService;
import com.sun.xml.internal.bind.v2.model.core.ID;
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.beans.factory.annotation.Autowired;
import org.springframework.security.core.context.SecurityContext;
import org.springframework.security.core.context.SecurityContextHolder;
import org.springframework.security.core.userdetails.User;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.annotation.RequestMapping;
import javax.servlet.http.HttpServletRequest;
import java.lang.reflect.Method;
import java.util.Date;

@Component
@Aspect
public class LogAop {
private Date visitTime;
private Class clazz;
private Method method;

@Autowired
private HttpServletRequest request;
@Autowired
private LogAopService logAopService;
//前置通知
@Before("execution(* com.smx.ssm.controller.*.*(..))")
public void doBefore(JoinPoint joinPoint) throws NoSuchMethodException {
    visitTime=new Date();
    clazz=joinPoint.getTarget().getClass();//得到访问的类
    String name = clazz.getName();
    if ("com.smx.ssm.controller.SysLogController".equals(name)){
        return;
    }else {
        String methodName = joinPoint.getSignature().getName();//得到访问的方法名
        Object[] args=null;
        args=joinPoint.getArgs();//得到方法参数
        if (args==null||0==args.length){
            method=clazz.getMethod(methodName);
        }else {
            Class[] classes=new Class[args.length];
            for (int i = 0; i <args.length; i++) {
                //if (args[i].getClass()==)
                classes[i]=  args[i].getClass();// 如果强转的话 会报java.lang.Integer cannot be cast to java.lang.Class 要得到数组的字节码文件
            }
            //Product product=new Product();
            method=clazz.getMethod(methodName,classes);//Class<?>... parameterTypes 接受一个class类型的数组 String.class
        }
    }

}
//后置通知
@After("execution(* com.smx.ssm.controller.*.*(..))")
public void doAfter(JoinPoint joinPoint){
    Long executionTime=new Date().getTime()-visitTime.getTime();//获取访问时长
    String url=null;
    if (clazz!=null&&method!=null&&clazz!=LogAop.class){
        RequestMapping classAnnotation = (RequestMapping) clazz.getAnnotation(RequestMapping.class);
        if (classAnnotation!=null){
            String[] classValue = classAnnotation.value();
            RequestMapping methodAnnotation = method.getAnnotation(RequestMapping.class);
            if (methodAnnotation!=null){
                String[] methodValue = methodAnnotation.value();
                url=classValue[0]+methodValue[0];//获取url
                //获取ip
                String ip=request.getRemoteAddr();
                //获取当前用户
                SecurityContext context = SecurityContextHolder.getContext();//request.getSession().getAttribute("SPRING_SECURITY_CONTEXT")
                User user = (User) context.getAuthentication().getPrincipal();//获取当前登录的用户
                String username = user.getUsername();
                SysLog sysLog=new SysLog();
                sysLog.setVisitTime(visitTime);
                sysLog.setMethod("[类名 ]"+clazz.getName()+"[方法名 ]"+method.getName());
                sysLog.setExecutionTime(executionTime);
                sysLog.setIp(ip);
                sysLog.setUrl(url);
                sysLog.setUsername(username);
                String name = clazz.getName();
                //logAopService.saveLog(sysLog);
            }
        }

    }

}

}