JSP分页时报空指针异常

walkman_22 2016-09-23 06:02:17

浏览器报500
[code=html
type Exception report

message

description The server encountered an internal error that prevented it from fulfilling this request.

exception

java.lang.NullPointerException
com.myweb.servlet.PageServlet.doGet(PageServlet.java:67)
javax.servlet.http.HttpServlet.service(HttpServlet.java:622)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
note The full stack trace of the root cause is available in the Apache Tomcat/8.0.36 logs.

][/code]

servlet代码



else if (dataSource.equals("cpu")) {

		    List<Cpu> list = new ArrayList<Cpu>();

		    list = new PageServlet().getAllCpuData(Integer.parseInt(cur));

		    int totalPage = new PageServlet().getTotalPage(dataSource);

		    request.setAttribute("tests", list);

		    request.setAttribute("totalPage", totalPage);

			//  MyWeb4 2016-9-11 updated 增加内存数据展示 end 

		   RequestDispatcher rd = request.getRequestDispatcher("../displayCPU.jsp");

		   rd.forward(request, response);

		}

displayCPU.jsp(文件名和位置都没有问题，只是传值的时候就出问题了。)



<ul>

    <c:forEach items="${requestScope.tests}" var="p">

      <li>名称：${p.cpuName}</li>

      <li>品牌：${p.cpuBrand}</li>

      <li>频率：${p.cpuFrequency}</li>

      <li>缓存：${p.cpuLevelThreeCache}</li>

      <li>接口：${p.cpuInterface}</li>

      <li>----------------------</li>

    </c:forEach>

    

  </ul>



  <c:if test="${param.cur == 1}">

    <a>首页</a>

    <a>上一页</a>

  </c:if>

  

  <c:if test="${param.cur != 1}">

    <a href="PageServlet?cur=1&dataSource=cpu">首页</a>

    <a href="PageServlet?cur=${param.cur - 1}&dataSource=cpu">上一页</a>

  </c:if>

  

  <c:if test="${param.cur == requestScope.totalPage}">

    <a>下一页</a>

    <a>尾页</a>

  </c:if>

  

  <c:if test="${param.cur != requestScope.totalPage}">

    <a href="PageServlet?cur=${param.cur + 1}&dataSource=cpu">下一页</a>

    <a href="PageServlet?cur=${requestScope.totalPage}&dataSource=cpu">尾页</a>

  </c:if>

  

  <p>

    当前第${param.cur}页       总共${requestScope.totalPage}页

  </p>