请高手帮忙看下！急！！！

[twtygah3617]

请问，这样的信息提示，一般是什么问题？
type Exception report

message

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

exception

org.apache.jasper.JasperException
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:512)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:395)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)


root cause

java.lang.NullPointerException
org.apache.jsp.login_jsp._jspService(login_jsp.java:72)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:334)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)


note The full stack trace of the root cause is available in the Apache Tomcat/5.5.20 logs.

[lblxiaoyu]

java.lang.NullPointerException
空指针异常


login_jsp.java:72)
看看这里写的什么

不行把代码贴出来

[twtygah3617]

下面是login.jsp，帮忙看下什么问题
<%@ page contentType="text/html;charset=gb2312" language="java"%>
<%@ page import="java.io.*,java.sql.*"%>
<jsp:useBean id="rst" scope="page" class="com.mingri.dbconn.DBResult"/>
<jsp:useBean id="calendar" scope="page" class="com.mingri.showtime.ShowTime"/>
<%
request.setCharacterEncoding("gb2312");//对请求进行统一编码，能正常接受到中文
String username=request.getParameter("username"); //接收表单中的username属性
String password=request.getParameter("password");//接收表单中的password属性
String str="select * from tb_user where "+
"username='"+username+"' and password='"+password+"'";
ResultSet rs=rst.getResult(str);//执行SQL语句获得结果集对象
session.setAttribute("isLog",new String("0"));//判断用户是否登陆，当isLog的属性为0时，说明用户并没有登陆
if(!rs.next())//结果集没有找到所要查找的行
{
out.println("<script language='javascript'>alert('用户名或密码错误');"+
"parent.location.href='login.html';</script>");
}
else
{
session.setAttribute("username",rs.getString("username"));//保存登录信息到session对象中
session.setAttribute("password",rs.getString("password"));
session.setAttribute("isLog",new String("1"));//将isLog属性设置为1
//获得用户上次登陆系统的时间
session.setAttribute("userLastLogTime",rs.getString("userLastLogTime"));
String strsql=calendar.getDate();
int id=rs.getInt("ID");
//将该用户本次登陆系统的时间在用户信息表中更新
String strUpdate="update tb_user set userLastLogTime='"+strsql+"' where ID="+id+"";
rst.getResult(strUpdate);//执行SQL语句
response.sendRedirect("chat.jsp");//登陆成功后转到系统主页面
}
%>

[lblxiaoyu]

<%@ page contentType="text/html;charset=gb2312" language="java"%> 
<%@ page import="java.io.*,java.sql.*"%> 
<jsp:useBean id="rst" scope="page" class="com.mingri.dbconn.DBResult"/> 
<jsp:useBean id="calendar" scope="page" class="com.mingri.showtime.ShowTime"/> 
<% 
	try{
	   request.setCharacterEncoding("gb2312");//对请求进行统一编码，能正常接受到中文 
	   String username=request.getParameter("username"); //接收表单中的username属性 
	   String password=request.getParameter("password");//接收表单中的password属性 
	   String str="select * from tb_user where "+ 
	               "username='"+username+"' and password='"+password+"'"; 
	   System.out.println("rst:"+rst);
	   System.out.println("str:"+str);
	   ResultSet rs=rst.getResult(str);//执行SQL语句获得结果集对象 
	   System.out.println("rs:"+rs);
	   session.setAttribute("isLog",new String("0"));//判断用户是否登陆，当isLog的属性为0时，说明用户并没有登陆 
	   if(rs.next()) {
		   System.out.println("gogogogog");
		 session.setAttribute("username",rs.getString("username"));//保存登录信息到session对象中 
	     session.setAttribute("password",rs.getString("password")); 
	     session.setAttribute("isLog",new String("1"));//将isLog属性设置为1 
	     //获得用户上次登陆系统的时间 
	     session.setAttribute("userLastLogTime",rs.getString("userLastLogTime")); 
	     String strsql=calendar.getDate(); 
	     int id=rs.getInt("ID"); 
	     //将该用户本次登陆系统的时间在用户信息表中更新 
	     String strUpdate="update tb_user set userLastLogTime='"+strsql+"' where ID="+id+""; 
	     rst.getResult(strUpdate);//执行SQL语句 
	     response.sendRedirect("chat.jsp");//登陆成功后转到系统主页面 	   
	   } else { 
		   out.println(" <script language='javascript'>alert('用户名或密码错误');"+ 
           "parent.location.href='login.html'; </script>"); 
	   } 
	} catch (Exception e) {
		System.out.println("Exception-e:"+e.getMessage());
	}
%> 

[lblxiaoyu]

试试这个 ，把打印出来的信息给我看看

[老紫竹]

楼主不知道
login_jsp.java
这个文件在哪里吗？

在你的 tomcat/works/catalina 下面的一个很深的子目录里面，搜索看看，
看看72行写的是啥？

[twtygah3617]

login_jsp.java:


package org.apache.jsp;

import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.jsp.*;
import java.io.*;
import java.sql.*;

public final class login_jsp extends org.apache.jasper.runtime.HttpJspBase
implements org.apache.jasper.runtime.JspSourceDependent {

private static java.util.List _jspx_dependants;

public Object getDependants() {
return _jspx_dependants;
}

public void _jspService(HttpServletRequest request, HttpServletResponse response)
throws java.io.IOException, ServletException {

JspFactory _jspxFactory = null;
PageContext pageContext = null;
HttpSession session = null;
ServletContext application = null;
ServletConfig config = null;
JspWriter out = null;
Object page = this;
JspWriter _jspx_out = null;
PageContext _jspx_page_context = null;


try {
_jspxFactory = JspFactory.getDefaultFactory();
response.setContentType("text/html;charset=gb2312");
pageContext = _jspxFactory.getPageContext(this, request, response,
null, true, 8192, true);
_jspx_page_context = pageContext;
application = pageContext.getServletContext();
config = pageContext.getServletConfig();
session = pageContext.getSession();
out = pageContext.getOut();
_jspx_out = out;

out.write('\n');
out.write('\n');
com.mingri.dbconn.DBResult rst = null;
synchronized (_jspx_page_context) {
rst = (com.mingri.dbconn.DBResult) _jspx_page_context.getAttribute("rst", PageContext.PAGE_SCOPE);
if (rst == null){
rst = new com.mingri.dbconn.DBResult();
_jspx_page_context.setAttribute("rst", rst, PageContext.PAGE_SCOPE);
}
}
out.write('\n');
com.mingri.showtime.ShowTime calendar = null;
synchronized (_jspx_page_context) {
calendar = (com.mingri.showtime.ShowTime) _jspx_page_context.getAttribute("calendar", PageContext.PAGE_SCOPE);
if (calendar == null){
calendar = new com.mingri.showtime.ShowTime();
_jspx_page_context.setAttribute("calendar", calendar, PageContext.PAGE_SCOPE);
}
}
out.write('\n');

request.setCharacterEncoding("gb2312");//对请求进行统一编码，能正常接受到中文
String username=request.getParameter("username"); //接收表单中的username属性
String password=request.getParameter("password");//接收表单中的password属性
String str="select * from tb_user where "+
"username='"+username+"' and password='"+password+"'";
ResultSet rs=rst.getResult(str);//执行SQL语句获得结果集对象
session.setAttribute("isLog",new String("0"));//判断用户是否登陆，当isLog的属性为0时，说明用户并没有登陆
if(!rs.next())//结果集没有找到所要查找的行
{
out.println("<script language='javascript'>alert('用户名或密码错误');"+
"parent.location.href='login.html';</script>");
}
else
{
session.setAttribute("username",rs.getString("username"));//保存登录信息到session对象中
session.setAttribute("password",rs.getString("password"));
session.setAttribute("isLog",new String("1"));//将isLog属性设置为1
//获得用户上次登陆系统的时间
session.setAttribute("userLastLogTime",rs.getString("userLastLogTime"));
String strsql=calendar.getDate();
int id=rs.getInt("ID");
//将该用户本次登陆系统的时间在用户信息表中更新
String strUpdate="update tb_user set userLastLogTime='"+strsql+"' where ID="+id+"";
rst.getResult(strUpdate);//执行SQL语句
response.sendRedirect("chat.jsp");//登陆成功后转到系统主页面
}

out.write("\n");
out.write("\n");
out.write("\n");
out.write("\n");
out.write("\n");
out.write("\n");
out.write("\n");
out.write("\n");
out.write("\n");
out.write("\n");
out.write("\n");
out.write("\n");
out.write("\n");
out.write("\n");
out.write("\n");
out.write("\n");
out.write("\n");
out.write("\n");
out.write("\n");
} catch (Throwable t) {
if (!(t instanceof SkipPageException)){
out = _jspx_out;
if (out != null && out.getBufferSize() != 0)
out.clearBuffer();
if (_jspx_page_context != null) _jspx_page_context.handlePageException(t);
}
} finally {
if (_jspxFactory != null) _jspxFactory.releasePageContext(_jspx_page_context);
}
}
}

[twtygah3617]

打印出来的信息没有变化！

[lblxiaoyu]

if(!rs.next())
就是这个 哈哈
这个结果集 应该没有取到东西

[lblxiaoyu]

楼主去查一下 看看
如果你的rs==null的时候你用rs.next() 就会报异常了啊

[twtygah3617]

那说明什么问题？要怎么修正呢？

[lblxiaoyu]

ResultSet rs=rst.getResult(str);//执行SQL语句获得结果集对象

看看这个后 rs 是否==null

如果这个为空

那你就要检查rst.getResult（）了，这个代码我也看不到阿 不知道你里边怎么实现的

类似问题解决方法：
1，检查数据库连接是否正确；
2，检查结果集是否取道了；
3，检查有没有关闭数据库连接后又使用结果集了

[太乙]

一般用 的时候都用
if(rs==null||!rs.next())
{

}