太奇怪的问题！我的最后30分奉上！虽有点少！但我有诚意！

yunrong 2002-05-22 04:55:22

这个程序昨天用还好使
为什么今天就有这样的错误！

表单提交的代码如下<%@ page language="java" import="java.sql.*"%>
<%@ page import ="java.util.*"%>
<%@ page contentType="text/html;charset=gb2312"%>
<html>
<head>
<title>user register</title>
</head>
<body>
<%
String userid=request.getParameter("userid");
String password=request.getParameter("password");
String confirm_password=request.getParameter("confirm_password");
String question=request.getParameter("question");
String answer=request.getParameter("answer");
String name=request.getParameter("name");
String sex=request.getParameter("sex");
String literacy=request.getParameter("literacy");
String mail=request.getParameter("mail");
String aihao=request.getParameter("aihao");
byte[] tmpbyte=userid.getBytes("ISO8859_1");
userid=new String(tmpbyte);
tmpbyte=password.getBytes("ISO8859_1");
password=new String(tmpbyte);
tmpbyte=confirm_password.getBytes("ISO8859_1");
confirm_password=new String(tmpbyte);
tmpbyte=question.getBytes("ISO8859_1");
question=new String(tmpbyte);
tmpbyte=answer.getBytes("ISO8859_1");
answer=new String(tmpbyte);
tmpbyte=name.getBytes("ISO8859_1");
name=new String(tmpbyte);
tmpbyte=literacy.getBytes("ISO8859_1");
literacy=new String(tmpbyte);
tmpbyte=aihao.getBytes("ISO8859_1");
aihao=new String(tmpbyte);
%>
<%
if((userid.length()==0)||(password.length()==0)||(confirm_password.length()==0))
out.println("登录名，密码，及密码校验不能为空！");
else if ((question.length()==0)||(answer.length()==0))
out.println("密码遗失提示问题及答案不能为空！");
else if (!password.equals(confirm_password))
out.println("密码与确认密码不一致！");
else if( mail.length()==0)
out.println("E-MAIL不能为空！");
else if(mail.indexOf('@')<=0)
out.println("EMAIL 地址有错误！");
else{
try{
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
String url="jdbc:odbc:nn";
Connection con=DriverManager.getConnection(url);
PreparedStatement select_stm=con.prepareStatement("select password from nn where userid=?");
select_stm.setString(1,userid);
ResultSet result=select_stm.executeQuery();
String temp_password=null;
if(result.next())
temp_password=result.getString(1);
result.close();

if (temp_password!=null)
out.println("这个用户名已存在，请再换一个名字注册！");
else
{ String sqlstr="select *from nn";
Statement stmt=con.createStatement();
sqlstr="insert into nn(userid,password,confirm_password,question,answer,name,sex,mail,literacy,aihao) values('"+userid+"','"+password+"','"+confirm_password+"', '"+question+"','"+answer+"','"+name+"','"+sex+"','"+mail+"','"+literacy+"','"+aihao+"')";
stmt.executeUpdate(sqlstr);
stmt.close();
}

%>
<%@ include file="succeed.jsp" %>
<%
}catch (Exception e){out.println(e);}
}
%>
</body>
</html>
****************************************************************************
错误是

500 Internal Server Error
/kk/register_action.jsp:

null
java.lang.NullPointerException
at jrun__kk__register_action2ejsp17._jspService(jrun__kk__register_action2ejsp17.java:69)
at allaire.jrun.jsp.HttpJSPServlet.service(HttpJSPServlet.java:40)
at allaire.jrun.servlet.JRunSE.service(JRunSE.java:1013)
at allaire.jrun.servlet.JRunSE.runServlet(JRunSE.java:925)
at allaire.jrun.servlet.JRunNamedDispatcher.forward(JRunNamedDispatcher.java:34)
at allaire.jrun.jsp.JSPServlet.service(JSPServlet.java:174)
at allaire.jrun.servlet.JRunSE.service(JRunSE.java:1013)
at allaire.jrun.servlet.JRunSE.runServlet(JRunSE.java:925)
at allaire.jrun.servlet.JRunRequestDispatcher.forward(JRunRequestDispatcher.java:88)
at allaire.jrun.servlet.JRunSE.service(JRunSE.java:1131)
at allaire.jrun.servlet.JvmContext.dispatch(JvmContext.java:330)
at allaire.jrun.http.WebEndpoint.run(WebEndpoint.java:107)
at allaire.jrun.ThreadPool.run(ThreadPool.java:267)
at allaire.jrun.WorkerThread.run(WorkerThread.java:74)

***********************************************************************
哪位高手帮帮忙！
感激万分！

...全文

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7 条回复

切换为时间正序

当前发帖距今超过3年，不再开放新的回复

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yunrong 2002-05-23

不愧是高手们
我找到问题所在了
是对空对象进行了操作，谢谢啦！
虽然分不多，请别见怪！

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可乐加水 2002-05-22

null
java.lang.NullPointerException基本上就是对空对象进行了操作,
所以在取得对象的时候应该先判断一下是不是为空的,按照Andrawu(Andrawu)的方法应该可以了

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Andrawu 2002-05-22

to weidegong(weidegong)
哪里哪里

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weidegong 2002-05-22

to Andrawu(Andrawu)
太敬业了

to yunrong (云容)
分不够？送你900分好了。。

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jspxnet 2002-05-22

有空

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wjfxiao 2002-05-22

如果userid是null，
user.length()肯定会报
java.lang.NullPointerException
用楼上的方法吧，应该没问题！

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Andrawu 2002-05-22

String userid=request.getParameter("userid")==null?"":request.getParameter("userid");
String password=request.getParameter("password")==null?"":request.getParameter("password");
String confirm_password=request.getParameter("confirm_password")==null?"":request.getParameter("confirm_password");
String question=request.getParameter("question")==null?"":request.getParameter("question");
String answer=request.getParameter("answer")==null?"":request.getParameter("answer");
String name=request.getParameter("name")==null?"":request.getParameter("name");
String sex=request.getParameter("sex")==null?"":request.getParameter("sex");
String literacy=request.getParameter("literacy")==null?"":request.getParameter("literacy");
String mail=request.getParameter("mail")==null?"":request.getParameter("mail");
String aihao=request.getParameter("aihao")==null?"":request.getParameter("aihao");

试试：
如果不行用
try{
.....
}catch(Exception se) {
se.printStackTrace(System.err);
}
得到错误的信息看看,还可以用out.println("aaa") ;一步一步的跟踪。