Question

java项目出现500错误是什么原因

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: An exception occurred processing JSP page /deletexuan.jsp at line 56

53: <%
54: String s="select * from xuan";
55: ResultSet rs=Li.getRs(s);
56: while(rs.next()){
57: out.print("<form action='DelScoreServlet'>");
58: String ss=rs.getString("xname");
59: out.print("<tr><td>"+ss+"</td><td>");

Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:505)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:416)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:337)
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.deletexuan_jsp._jspService(deletexuan_jsp.java:121)
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:374)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:337)
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/6.0.16 logs.
Apache Tomcat/6.0.16

Answer 1

54: String s="select * from xuan";
55: ResultSet rs=Li.getRs(s);
56: while(rs.next()){

检查下Li和rs是不是为空

追问

那个DBHandler里面设的rs就是为空，改了是不是就好了？Li是jsp:useBean的id啊，不是空啊