求助！大神给看看这是什么情况？tomcat运行一个基于BS的学生成绩管理系统时出的状况
type Exception reportmessage
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 /checkLogin.jsp at line 21
18: if(rs==null)
19: System.out.println("rs==null");
20: try{
21: rs.next();
22: rowCount=1;
23: }catch(SQLException e){}
24: if(rowCount!=0&&certCode.equals((String)session.getAttribute("certCode"))){
Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:515)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:426)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:320)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:266)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
root cause
java.lang.NullPointerException
org.apache.jsp.checkLogin_jsp._jspService(checkLogin_jsp.java:75)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:384)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:320)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:266)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
note The full stack trace of the root cause is available in the Apache Tomcat/6.0.10 logs.
--------------------------------------------------------------------------------
tomcat exception report null --------------------编程问答-------------------- 18: if(rs==null)
19: System.out.println("rs==null");
20: try{
21: rs.next();
22: rowCount=1;
23: }catch(SQLException e){}
24: if(rowCount!=0&&certCode.equals((String)session.getAttribute("certCode"))){
如果rs为null,你再调用rs.next()方法肯定报空指针异常 --------------------编程问答-------------------- 那该如何修改呢？ --------------------编程问答-------------------- 之前我用rs里数据的时候 是用while循环的
--------------------编程问答--------------------
很久没这么直接用rs了
--------------------编程问答--------------------
大神能把修改后的语句发给我么？麻烦了~
--------------------编程问答--------------------
我修改了几次都不成功
--------------------编程问答--------------------
if(rs==null)19: {
System.out.println("rs==null");
return ;//增加退出
}
20: try{
21: rs.next();
22: rowCount=1;
23: }catch(SQLException e){}
24: if(rowCount!=0&&certCode.equals((String)session.getAttribute("certCode"))){
补充：Java , Eclipse
