org.apache.jasper.JasperException: An exception occurred processing JSP page /Admin/admin_main.jsp

List list = (List)request.getAttribute("list");
1.建议在此句之后 打印出 list 对象,看看是否为null,应该是你request.setAttribute("list",list);这里的list就是个null
2.一点建议:用list之前先判断以下 if(list!=null){才做相应的处理}