我將bean對象從servlet傳遞給jsp文件,並且想要如下使用bean值,但會引發運行時錯誤。我究竟做錯了什麼?如何在jsp文件中使用從servlet傳遞的bean值
<%@ page import = "beans.UserInfo" %>
<%
UserInfo userInfo = (UserInfo)session.getAttribute("userInfo");
String userName = userInfo.getUserName();
%>
Exeption如下:
例外
org.apache.jasper.JasperException:顯示java.lang.NullPointerException org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java :491) org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:419) org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313) org.apache.jasper.servlet。 JspServlet.service(JspServlet.java:2 60) javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
根源
顯示java.lang.NullPointerException org.apache.jsp.Login_jsp._jspService(Login_jsp.java:60 ) org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70) javax.servlet.http.HttpServlet.service(HttpServlet.java:717) org.apache.jasper.servlet.JspServletWrapper.service( JspServletWrapper.java:377) org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313) org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260) javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
note注意Apache Tomcat/6.0.28日誌中提供了根本原因的完整堆棧跟蹤。
您應該*包含異常堆棧跟蹤。 – adatapost