空指针有关问题`高手快来`
日期：2014-05-18 浏览次数：20867 次
空指针问题``高手快来``
这个程序那里有问题吗?
<%@ page contentType= "text/html;charset=gb2312 "%>
<%@ page import= "java.sql.* "%>
<%@ page import= "javax.sql.* "%>
<%@ page import= "javax.naming.* "%>
<html>
<head> <title> jsp登录页面 </title> </head>
<body>
<center>
<%
request.setCharacterEncoding( "gb2312 ");
String name=request.getParameter( "name ");
String password=request.getParameter( "password ");
Connection conn=null;
Statement stmt=null;
PreparedStatement pstmt=null;
ResultSet rs=null;
String sql=null;
%>
<%
sql= " select * from zhuce where name=? ";
Context ctx =new InitialContext();
DataSource ds=(DataSource)ctx.lookup( "java:comp/env/jdbc/luntan ");
conn=ds.getConnection();
rs=stmt.executeQuery(sql);
if(!rs.next())
{
try{
pstmt=conn.prepareStatement( "insert into zhuce(name,password)values(?,?) ");
pstmt.setString(1,name);
pstmt.setString(2,password);
pstmt.executeQuery();
out.println(name);
out.println(password);
}
catch(Exception e)
{e.printStackTrace();}
%>
<jsp:forward page= "success.jsp "/>
<%
rs.close();
pstmt.close();
conn.close();
}
else
{
%>
<jspj:forward page= "failure.jsp "/>
<%
}
%>
</center>
</body>
</html>
<%@ page contentType= "text/html;charset=gb2312 "%>
<html>
<head>
<title> 注册页面 </title>
</head>
<body>
<center>
<h1> 注册页面 </h1> <br>
<hr>
<br>
<br>
<br>
<form action= "judge.jsp " method= "post ">
<table>
<tr>
<td> 用户名: </td>
<td> <input type= "text " name= "name "/> </td>
</tr>
<tr>
<td> 密  码 </td>
<td> <input type= "password " name= "password "/> </td>
</tr>
<tr>
<td> <input type= "submit " value= "注册 "/> </td>
<td> <input type= "reset " value= "重置 "/
这个程序那里有问题吗?
<%@ page contentType= "text/html;charset=gb2312 "%>
<%@ page import= "java.sql.* "%>
<%@ page import= "javax.sql.* "%>
<%@ page import= "javax.naming.* "%>
<html>
<head> <title> jsp登录页面 </title> </head>
<body>
<center>
<%
request.setCharacterEncoding( "gb2312 ");
String name=request.getParameter( "name ");
String password=request.getParameter( "password ");
Connection conn=null;
Statement stmt=null;
PreparedStatement pstmt=null;
ResultSet rs=null;
String sql=null;
%>
<%
sql= " select * from zhuce where name=? ";
Context ctx =new InitialContext();
DataSource ds=(DataSource)ctx.lookup( "java:comp/env/jdbc/luntan ");
conn=ds.getConnection();
rs=stmt.executeQuery(sql);
if(!rs.next())
{
try{
pstmt=conn.prepareStatement( "insert into zhuce(name,password)values(?,?) ");
pstmt.setString(1,name);
pstmt.setString(2,password);
pstmt.executeQuery();
out.println(name);
out.println(password);
}
catch(Exception e)
{e.printStackTrace();}
%>
<jsp:forward page= "success.jsp "/>
<%
rs.close();
pstmt.close();
conn.close();
}
else
{
%>
<jspj:forward page= "failure.jsp "/>
<%
}
%>
</center>
</body>
</html>
<%@ page contentType= "text/html;charset=gb2312 "%>
<html>
<head>
<title> 注册页面 </title>
</head>
<body>
<center>
<h1> 注册页面 </h1> <br>
<hr>
<br>
<br>
<br>
<form action= "judge.jsp " method= "post ">
<table>
<tr>
<td> 用户名: </td>
<td> <input type= "text " name= "name "/> </td>
</tr>
<tr>
<td> 密  码 </td>
<td> <input type= "password " name= "password "/> </td>
</tr>
<tr>
<td> <input type= "submit " value= "注册 "/> </td>
<td> <input type= "reset " value= "重置 "/
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