<%@ page language="java" import="java.util.*,java.sql.*,com.FamilyEducation.db.*" pageEncoding="gb2312"%>
<%
response.setContentType("text/xml");
response.setHeader("Cache-Control","no-store");
response.setHeader("pragma","no-cache");
response.setDateHeader("Expirse",0); String name = request.getParameter("username");
out.print(name);
DBConn dbcn = new DBConn();
Connection conn = dbcn.getConn();
String sql = "select * from teacherreg where id = '"+name+"' ";
Statement stmt=conn.createStatement();
ResultSet rs=stmt.executeQuery(sql);
if(rs.next()==true)
response.getWriter().write("用户名已存在");
else
response.getWriter().write("可用");
%>
这个是我的check.jsp页面的代码,作用是进行验证,我知道String name = request.getParameter("username");
这句有问题。是不是,没有进行刷新跳转,就不能用这个语句。
解释:username是文本框的name,
出现问题:
通过数据库一直查查询不到数据,通过alert,发现out.print(name);返回去的值是null,所以sql语句不起作用。
小弟想在check.jsp该页面取到前一页面user_reg.jsp的文本框name="username"的值.
希望各位大哥帮帮小弟!!
<%
response.setContentType("text/xml");
response.setHeader("Cache-Control","no-store");
response.setHeader("pragma","no-cache");
response.setDateHeader("Expirse",0); String name = request.getParameter("username");
out.print(name);
DBConn dbcn = new DBConn();
Connection conn = dbcn.getConn();
String sql = "select * from teacherreg where id = '"+name+"' ";
Statement stmt=conn.createStatement();
ResultSet rs=stmt.executeQuery(sql);
if(rs.next()==true)
response.getWriter().write("用户名已存在");
else
response.getWriter().write("可用");
%>
这个是我的check.jsp页面的代码,作用是进行验证,我知道String name = request.getParameter("username");
这句有问题。是不是,没有进行刷新跳转,就不能用这个语句。
解释:username是文本框的name,
出现问题:
通过数据库一直查查询不到数据,通过alert,发现out.print(name);返回去的值是null,所以sql语句不起作用。
小弟想在check.jsp该页面取到前一页面user_reg.jsp的文本框name="username"的值.
希望各位大哥帮帮小弟!!
var req;
function check_name(){
var str=document.getElementById("userid");
var url="check.jsp?id="+num;
if (window.XMLHttpRequest) {
req = new XMLHttpRequest();
}
else if (window.ActiveXObject) {
req= new ActiveXObject("Microsoft.XMLHTTP");
}
req.open("GET",url,true);
req.onreadystatechange=callback;
req.send(null);
}
function callback(){
if(req.readyState==4)
if(req.status==200)
{
alert(req.responseText);
document.getElementById('ckname').innerHTML="<font color='green'>"+req.responseText+"</font>";
}
}
function check_name(){
var str=document.getElementById("userid");
var url="check.jsp?id="+num;
if (window.XMLHttpRequest) {
req = new XMLHttpRequest();
}
else if (window.ActiveXObject) {
req= new ActiveXObject("Microsoft.XMLHTTP");
}
req.open("GET",url,true);
req.onreadystatechange=callback;
req.send(null);
}
function callback(){
if(req.readyState==4)
if(req.status==200)
{
alert(req.responseText);
document.getElementById('ckname').innerHTML="<font color='green'>"+req.responseText+"</font>";
}
}
var str=document.getElementById("userid");
var url="check.jsp?id="+name;
根本没看见你在JS中定义name,不要把JS的变量跟JSP的变量搞混,修改为:
var str=document.getElementById("userid").value;
var url="check.jsp?id="+str;
alert(url); // 自己先检查下这个URL是否如你所料。
check?id=xxxx所以跟你的参数名保持一致:
String name = request.getParameter("id");
String name = request.getParameter("id");获取之后,需要判空,不然容易报null。<%@ page language="java" import="java.util.*,java.sql.*,com.FamilyEducation.db.*" pageEncoding="gb2312"%>
<%
response.setContentType("text/xml");
response.setHeader("Cache-Control","no-store");
response.setHeader("pragma","no-cache");
response.setDateHeader("Expirse",0);String name = request.getParameter("username");DBConn dbcn = new DBConn();
Connection conn = dbcn.getConn();
String sql = "select * from teacherreg where id = '"+ name +"' ";
Statement stmt=conn.createStatement();
ResultSet rs=stmt.executeQuery(sql);if(rs.next())
response.getWriter().write("用户名已存在");
else
response.getWriter().write("可用");
%>