大家帮我看看问题怎么解决啊,初学,多谢!
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:103)
root cause
java.lang.NullPointerException
org.apache.jsp.TestServer1_jsp._jspService(TestServer1_jsp.java:73)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:94)
javax.servlet.http.HttpServlet.service(HttpServlet.java:103)
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:103)
note The full stack trace of the root cause is available in the Apache Tomcat/5.0.30 logs.
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空指针异常，源码呢？
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jsp里抛出来的是瓦
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<!-导入程序所需的相应的包packages,一般jsp中进行数据库操作都可以引入这些类包->
<%@ page info="database handler"%>
<%@ page import="java.io.*"%>
<%@ page import="java.util.*"%>
<%@ page import="java.sql.*"%>
<%@ page import="javax.servlet.*"%>
<%@ page import="javax.servlet.http.*"%>
<html>
<head>
<title>信息查询</title>
</head>
<body>
<% String kind="";
String keyword="";
request.setCharacterEncoding("GB2312");
kind=request.getParameter("kind");
keyword=request.getParameter("keyword");%>
<% String attribute="";
if(kind.equals("职工号")) attribute="职工号";
else if(kind.equals("姓名")) attribute="姓名";
else if(kind.equals("性别")) attribute="性别";
else if(kind.equals("参加工作")) attribute="参加工作";%>
<% try{
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver").newInstance();
String url="jdbc:odbc:employees";
Connection conn=DriverManager.getConnection(url,"","");
Statement smt=conn.createStatement();
String sql="Select * from worker where "+attribute+" like'"+keyword+"'";
ResultSet rs=smt.executeQuery(sql);
out.print("<TABLE BORDER>");
out.print("<CAPTION><H2>本次浏览数据库的结果如下</CAPTION>");
out.print("<TR align=center>");%>
<%
out.print("<TD>职工号</TD><TD>姓名</TD><TD>性别</TD><TD>参加工作</TD></TR>");
while(rs.next()){
out.print("<TR>");
for(int i=1;i<=rs.getMetaData().getColumnCount();i++){
out.print("<TD>");
out.print(rs.getObject(i)+"\t");
out.print("</TD>");}
out.print("<TD><A href=http://>请点击这里</A></TD>");
out.println("</TR>");}
out.print("</TABLE>");
rs.close();
smt.close();
conn.close();
}catch(Exception e){out.println(e.toString());}
%>
</body>
</html>
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你可以去TOMACT的WORK目录下面找到 你这个项目的文件 然后查看一下
TestServer1_jsp._jspService(TestServer1_jsp.java:73)
这句是什么，然后跟着这个查吧
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<% String kind="";
String keyword="";
request.setCharacterEncoding("GB2312");
kind=request.getParameter("kind");
keyword=request.getParameter("keyword");%>
这是你的代码,如果你还有另外一个JSP页面的话,上面的两个红色的变量名如果在另外一个页面没有的话,
request.getParameter将返回一个Null,同时你这个Servlet中的kind和keyword也将会被设置为Null,在下
面的代码中你必须判断是否为Null,并且做出处理.所以会给你报出一个空指针的异常!
LZ我具体也不知道你别的页面的代码,所以猜测了一下,不知道对不对.
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还有,如果你就这一个页面的话，错误肯定是我刚才说的那里,第一次onload你的页面的时候,request.getParameter就开始工作了,结果肯定是Null
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我明白了!多谢!
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呵呵，不客气!
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我找到了TestServer1_jsp 但又出现了问题!
Exception report
message
description The server encountered an internal error () that prevented it from fulfilling this request.
exception
org.apache.jasper.JasperException: Unable to compile class for JSP
An error occurred at line: 24 in the jsp file: /textsql.jsp
Generated servlet error:
C:\Program Files\Apache Software Foundation\Tomcat 5.0\work\Catalina\localhost\_\org\apache\jsp\textsql_jsp.java:78: "try" ??? "catch" ? "finally"
try{
^
1 ??
org.apache.jasper.compiler.DefaultErrorHandler.javacError(DefaultErrorHandler.java:84)
org.apache.jasper.compiler.ErrorDispatcher.javacError(ErrorDispatcher.java:332)
org.apache.jasper.compiler.Compiler.generateClass(Compiler.java:437)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:497)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:476)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:464)
org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:511)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:295)
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:103)
note The full stack trace of the root cause is available in the Apache Tomcat/5.0.30 logs.
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