求助:jsp登陆出现错误,源码和错误如下,请指点.OK马上给分.多谢

[luoxingke]

chk-user.jsp
<%@ page contentType="text/html;charset=gb2312" %>
<jsp:useBean id="mybean" scope="page" class="dbbag.db"/>
<%
user_name=(String)(request.getParameter("user_name"));
user_pwd=(String)(request.getParameter("user_pwd"));
String sSql="select * from tb_user where user_name='" + user_name + "' ";
String str="";
String user_xm="";
int user_id;
String role_id="";
mybean.sqlDriver();
mybean.sqlQuery(sSql);
if(!mybean.rs.next())
{
response.sendRedirect("default.jsp");
}
else
{
if(mybean.rs.getString("user_sta").equals("0"))
{
if(!mybean.rs.getString("user_pwd").equals(user_pwd))
{
response.sendRedirect("default.jsp");
}
else
{
user_id=mybean.rs.getInt("user_id");
user_xm=mybean.rs.getString("user_xm");
role_id=mybean.rs.getString("role_id");
session.setAttribute("user_id",String.valueOf(user_id));
session.setAttribute("user_xm",user_xm);
session.setAttribute("role_id",role_id);
response.sendRedirect("index.jsp");
}
}
else
{
response.sendRedirect("default.jsp");
}

}
%>
错误信息:
HTTP Status 500 -

--------------------------------------------------------------------------------

type Exception report

message

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

exception

org.apache.jasper.JasperException: Unable to compile class for JSP

An error occurred at line: 2 in the jsp file: /chk-user.jsp

Generated servlet error:
[javac] Compiling 1 source file

D:\Tomcat\work\Standalone\localhost\examples\chk_0002duser_jsp.java:58: cannot resolve symbol
symbol : variable user_name
location: class org.apache.jsp.chk_0002duser_jsp
user_name=(String)(request.getParameter("user_name"));
^



An error occurred at line: 2 in the jsp file: /chk-user.jsp

Generated servlet error:
D:\Tomcat\work\Standalone\localhost\examples\chk_0002duser_jsp.java:59: cannot resolve symbol
symbol : variable user_pwd
location: class org.apache.jsp.chk_0002duser_jsp
user_pwd=(String)(request.getParameter("user_pwd"));
^



An error occurred at line: 2 in the jsp file: /chk-user.jsp

Generated servlet error:
D:\Tomcat\work\Standalone\localhost\examples\chk_0002duser_jsp.java:60: cannot resolve symbol
symbol : variable user_name
location: class org.apache.jsp.chk_0002duser_jsp
String sSql="select * from tb_user where user_name='" + user_name + "' ";
^



An error occurred at line: 2 in the jsp file: /chk-user.jsp

Generated servlet error:
D:\Tomcat\work\Standalone\localhost\examples\chk_0002duser_jsp.java:75: cannot resolve symbol
symbol : variable user_pwd
location: class org.apache.jsp.chk_0002duser_jsp
if(!mybean.rs.getString("user_pwd").equals(user_pwd))
^
4 errors

[jkit]

user_name和user_pwd没有定义。
在前面加上String user_name = null; String user_pwd = null;

[wangwd]

哈哈，你的user_name user_pwd没有定义呀。
你改成
String user_name=(String)(request.getParameter("user_name"));
String user_pwd=(String)(request.getParameter("user_pwd"));

[pleonheart]

String user_name=(String)request.getParameter("user_name");
String user_pwd=(String)request.getParameter("user_pwd");
楼上好快

[seaman0916]

哈哈,user_name ,user_pwd 未定义!

JSP 的编译器 的出错提示信息挺好的呀!
你怎么不研究研究出错信息 ? 对于一个程序员,能迅速找到出错问题的所在,也是一项很重要的素质! 我是这么认为的!

愚见! 海涵!

[timtin0361]

String user_name=request.getParameter("user_name");
String user_pwd=request.getParameter("user_pwd");

[hotsu]

seaman0916(沙漠孤鹰) 的意见的确不错，你要加油研究问题哦。：）

[wfeng007]

难道楼主是asp转来的？。。。。。。。嘿嘿。。。

[kingssman]

既然大家已经把正确答案说出来了，我就不再画蛇添足了。十分赞成seaman0916(沙漠孤鹰) 的意见~~~~~~~~~

[xqi8]

seaman0916(沙漠孤鹰) 说的没错！

[luoxingke]

错误又来了!!
HTTP Status 500 -
type Exception report

message

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

exception

org.apache.jasper.JasperException
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:248)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:295)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:241)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:247)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:260)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:493)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at org.apache.catalina.core.StandardContext.invoke(StandardContext.java:2415)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:180)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
at org.apache.catalina.valves.ErrorDispatcherValve.invoke(ErrorDispatcherValve.java:170)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:172)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:174)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at org.apache.coyote.tomcat4.CoyoteAdapter.service(CoyoteAdapter.java:223)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:432)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:386)
at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:534)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:530)
at java.lang.Thread.run(Thread.java:536)


root cause

java.lang.NullPointerException
at org.apache.jsp.chk_0002duser_jsp._jspService(chk_0002duser_jsp.java:67)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:137)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:204)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:295)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:241)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:247)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:260)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:493)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at org.apache.catalina.core.StandardContext.invoke(StandardContext.java:2415)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:180)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
at org.apache.catalina.valves.ErrorDispatcherValve.invoke(ErrorDispatcherValve.java:170)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:172)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:174)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at org.apache.coyote.tomcat4.CoyoteAdapter.service(CoyoteAdapter.java:223)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:432)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:386)
at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:534)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:530)
at java.lang.Thread.run(Thread.java:536)

[luoxingke]

这个页面昨天晚上已经调好通过了的,但是下午就不行了.其实开始我就是按照大哥们指点的那样做的,昨天好好的,今天就出问题了,好怪.不知道是不是tomcat的问题???

[pleonheart]

java.lang.NullPointerException
空指针异常，哪个变量没赋值，但被执行了
看chk_0002duser_jsp代码的第67行