老师这个是什么错误

HTTP Status 404 – 未找到

Type Status Report

消息 /sm/department/../department_list.jsp

描述 源服务器未能找到目标资源的表示或者是不愿公开一个已经存在的资源表示。

Apache Tomcat/8.5.47

老师这个是什么问题 

package com.zy.sm.controller;

import com.zy.sm.entity.Department;
import com.zy.sm.service.DepartmentService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.List;

/**
 * @author zhangyi
 */
@Controller("departmentController")
public class DepartmentController {
    @Autowired
    private DepartmentService departmentService;

    /**
     * /department/list.do   /department_list.jsp
     * @param request
     * @param response
     */
    public void list(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        List<Department> list = departmentService.getAll();
        request.setAttribute("List", list);
        request.getRequestDispatcher("../department_list.jsp").forward(request,response);
    }
}