JSP出错问题

JSP出错问题

import java.io.*;
import java.sql.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class ShowServlet extends HttpServlet{
@Override
public void init(ServletConfig config)throws ServletException{
super.init(config);
}

@Override
public void doPost(HttpServletRequest request,HttpServletResponse response) throws ServletException,IOException{
ConnectDB cont=new ConnectDB();
ShowCheck showcheck=new ShowCheck();
String s=(String) request.getAttribute("gname");
String str="select * from infotable where username='"+s+"'";
cont.executeQuery(str);
showcheck.setResultSet(cont.getResultSet());
try{
boolean s1=showcheck.getResultSet().next();
if(s1){response.sendRedirect("login.jsp");}
}catch(SQLException e){System.out.print(e);}
cont.close();
RequestDispatcher c_dispatcher=request.getRequestDispatcher("show.jsp");
c_dispatcher.forward(request, response);
}
@Override
public void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException,IOException{
doPost(request,response);
}
}

出现以下错误：
org.apache.jasper.JasperException: java.lang.NullPointerException
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:522)
org.apache.jasper.servlet.JspServletWrapper.service(

root cause

java.lang.NullPointerException
bean.ShowCheck.getString(ShowCheck.java:35)
org.apache.jsp.show_jsp._jspService(show_jsp.java:74)
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:374)
org.apache.jasper.servlet.JspServlet.serviceJspFile
try{
while(rs.next()){ //35行
for(int i=0;i<5;i++){
buffer.append("<tr>");
buffer.append("<th>"+rs.getString(i)+"</th>");
buffer.append("</tr>");
}
buffer.append("<th><Input type=checkbox name=ch value=");
buffer.append(j);
buffer.append(" </th>");
j=j+1;
}
}catch(SQLException e1){System.out.print(e1);}

您可能感兴趣问答

Collapsible

热门标签

热点问答