Java开发网 - 菜鸟问题，希望大虾们帮助

Topic: 菜鸟问题，希望大虾们帮助

1.菜鸟问题，希望大虾们帮助

Posted by: J2EE1982
Posted on: 2005-08-16 07:42

jsp:源程序

<%@ page language = "java" contentType = "text/html;charset=ISO-8859-1" %>
<%@ page import = "java.sql.*" %>
<jsp:useBean id="mysql" scope="page" class="com.Mysql" />
<%
ResultSet rs = mysql.executeQuery("select * from stsnews");
while(rs.next()) {
out.println(rs.getString("title"));
}
%>

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
  org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:372)
  org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:292)
  org.apache.jasper.servlet.JspServlet.service(JspServlet.java:236)
  javax.servlet.http.HttpServlet.service(HttpServlet.java:802)

root cause

java.lang.NullPointerException
  org.apache.jsp.index_jsp._jspService(index_jsp.java:59)
  org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:94)
  javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
  org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:324)
  org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:292)
  org.apache.jasper.servlet.JspServlet.service(JspServlet.java:236)
  javax.servlet.http.HttpServlet.service(HttpServlet.java:802)

2.Re:菜鸟问题，希望大虾们帮助 [Re: J2EE1982]	Copy to clipboard
Posted by: chengbd Posted on: 2005-08-17 01:12 java.lang.NullPointerException 这是运行时错误了，没看到你的DB连接代码，应该是rs是个null值，却执行rs.next()，就出错了。应该 ResultSet rs = mysql.executeQuery("select * from stsnews"); if(rs==null){ } else { while(rs.next()) { out.println(rs.getString("title")); } }