输入用户密码，会转入空页面，什么反映也没有。
当进入新用户注册页面后，所有信息填写完成，会出现下面的错误。
type Exception report

message

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

exception

org.apache.jasper.JasperException: An exception occurred processing JSP page /regist_config.jsp at line 24

21:  String question=request.getParameter("question");
22:     CountTime time=new CountTime();
23:        String str="select Name from tb_customer where Name='"+name+"'";
24:  ResultSet rs=connection.executeQuery(str);
25:  if(rs.next()){
26: %>
27: <script language="javascript">


Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:521)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:430)
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)

root cause

java.lang.NullPointerException
com.wy.JDBConnection.executeQuery(JDBConnection.java:27)
org.apache.jsp.regist_005fconfig_jsp._jspService(regist_005fconfig_jsp.java:88)
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:388)
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)