疯了 疯了! 快来救小弟我~

疯了 疯了!!!~~~ 快来救我~~~~~~
exception  

org.apache.jasper.JasperException:   Exception   in   JSP:   /chklogin.jsp:11

8:   String   sql   =   "SELECT   *   FROM   userpassword   WHERE   USER_ID= ' "+userid+ " '   AND   USER_PASSWORD= ' "+password+ " ' ";
9:     DBSQLManager   dbsm   =   new   DBSQLManager();
10:     dbsm.setsqlstr(sql);
11:     dbsm.executequery();
12:   ResultSet   rs   =     dbsm.getrs();
13:   if   (!rs.next())  
14:           {


Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:467)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:389)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:315)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)


root   cause  

java.lang.NullPointerException
shell.DBSQLManager.executequery(DBSQLManager.java:59)
org.apache.jsp.chklogin_jsp._jspService(chklogin_jsp.java:84)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:98)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:328)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:315)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)


下面是相关的文件.
package   shell;


import   java.sql.*;
import   shell.*;
public   class   DBSQLManager
{
protected   Connection   conn=null;
protected   Statement   stmt=null;
protected   ResultSet   rs=null;
protected   String   sqlstr;

public   DBSQLManager()
{
try
{
sqlstr= " ";

DBConnectionManager   dcm=new   DBConnectionManager();
conn=dcm.getconnection();
stmt=conn.createStatement();


}  
catch   (Exception   e)
{
e.printStackTrace();
}
}

public   Statement   getstmt()
{
return   stmt;
}

public   Connection   getconn()
{
return   conn;
}

public   ResultSet   getrs()
{
return   rs;
}

public   void   setsqlstr(String   newsqlstr)
{
this.sqlstr=newsqlstr;
}

public   String   getsqlstr()
{
return   sqlstr;
}

public   void   executequery()   throws   Exception
{

rs=stmt.executeQuery(sqlstr);


}

public   void   execeteupdate()   throws   Exception
{
stmt.executeUpdate(sqlstr);
}

public   void   close()   throws   SQLException
{
if(stmt!=   null)
{
stmt.close();
stmt=null;
}
conn.close();
conn=null;
}

}


下面是chklogin.jsp
<%@page   contentType= "text/html;charset=gb2312 "%>
<%@   include   file= "incoming/common.jsp "%>

<%

String   userid   =   new   String(request.getParameter( "userid ").trim().getBytes( "ISO-8859-1 "));
String   password   =   new   String(request.getParameter( "password ").trim().getBytes( "ISO-8859-1 "));
 
String   sql   =   "SELECT   *   FROM   userpassword   WHERE   USER_ID= ' "+userid+ " '   AND   USER_PASSWORD= ' "+password+ " ' ";
  DBSQLManager   dbsm   =   new   DBSQLManager();
  dbsm.setsqlstr(sql);
  dbsm.executequery();
ResultSet   rs   =     dbsm.getrs();
if   (!rs.next())  
        {
    String   errmsg= "error1 ";
    response.sendRedirect( "login.jsp?errmsg= "+errmsg);
    return;
        }  
       
request.getSession(true);
String   chk= "true ";
session.setAttribute( "Enter ",chk);
session.setAttribute( "userid ",userid);
response.sendRedirect( "booklist.jsp ");
%>




[解决办法]
DBSQLManager.java:59行

stmt没有创建成功吧
[解决办法]
在chklogin.jsp中加入
<% page import= "*/DBSQLManager "%> 即DBSQLManager婁路徑
[解决办法]
DBConnectionManager 类代码发下看
[解决办法]
可以在控制台打印跟踪的啊！
[解决办法]
eclipse怎么调试还要教啊？大哥。
如果你是发布到tomcat的话，你设个断点。走到那儿，它就停下了。
你要是想通过控制台的话也可以。写个main函数，运行调试一下有main函数的文件。