求教一个问题 问题是这样的:在一个用户名框失去输入焦点的时候自动进行用户名(自动连接到数据库)检测? 解决方案 » 免费领取超大流量手机卡,每月29元包185G流量+100分钟通话, 中国电信官方发货 js就行 onblur触发一个action ajax 可以实现,如下所示:login.jsp<%@ page contentType="text/html;charset=GB2312" language="java" %><head> <META http-equiv=Content-Type content="text/html; charset=GB2312"> <style> span{ color:red; font-size:12px; text-indent:2em; } </style></head><script language="javascript"> var XMLHttpReq = false; //创建XMLHttpRequest对象 function createXMLHttpRequest() { if(window.XMLHttpRequest) { //Mozilla 浏览器 XMLHttpReq = new XMLHttpRequest(); } else if (window.ActiveXObject) { // IE浏览器 try { XMLHttpReq = new ActiveXObject("Msxml2.XMLHTTP"); } catch (e) { try { XMLHttpReq = new ActiveXObject("Microsoft.XMLHTTP"); } catch (e) {} } } } //发送请求函数 function sendRequest(url) { createXMLHttpRequest(); XMLHttpReq.open("GET", url, true); XMLHttpReq.onreadystatechange = processResponse;//指定响应函数 XMLHttpReq.send(null); // 发送请求 } // 处理返回信息函数 function processResponse() { if (XMLHttpReq.readyState == 4) { // 判断对象状态 if (XMLHttpReq.status == 200) { // 信息已经成功返回,开始处理信息 var res=XMLHttpReq.responseXML.getElementsByTagName("res")[0].firstChild.data; document.getElementById("cn").innerHTML=res; } } } // 身份验证函数 function checkUsername() { var username=document.getElementById("username").value; var url="CheckUsername?username="+ username; sendRequest(url);}</script><body vLink="#006666" link="#003366" bgColor="#E0F0F8"><form action="" method="post" name="form">用户名: <input size="15" type="text" name="username"onblur="checkUsername()" onkeypress="checkUsername()" onkeyup="checkUsername()" onkeydown="checkUsername()" /><span id="cn"></span><p>密 码: <input type="password" size="15" name="psw"><p><input type="button" value="登录" onclick="checkUsername()" ></form>CheckUsername.javapackage com.sum;import java.io.IOException;import java.io.PrintWriter;import javax.servlet.ServletConfig;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;public class CheckUsername extends HttpServlet { public void init(ServletConfig config) throws ServletException { } /* * 处理<GET> 请求方法. */ protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //设置接收信息的字符集 request.setCharacterEncoding("UTF-8"); //接收浏览器端提交的信息 String username = request.getParameter("username"); //设置输出信息的格式及字符集 response.setContentType("text/xml; charset=UTF-8"); response.setHeader("Cache-Control", "no-cache"); //创建输出流对象 PrintWriter out = response.getWriter(); //依据验证结果输出不同的数据信息 out.println("<response>"); if(username.equals("jenny")){ out.println("<res>" + "热烈的欢迎您!" + "</res>"); }else{ out.println("<res>" + "对不起,登录失败!" + "</res>"); } out.println("</response>"); out.close(); } /* * 处理<POST> 请求方法. */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); }} 为什么spring的事务管理要放到服务层?小弟一直不明,请举例子说明一下!谢谢! 【【tomcat客户端请求链接2个疑问 ???】】 关于联动的问题请教各位高手 求助java.net.URLEncoder.encode解码 问一个<jsp:include />的问题 请问:如何在一个Tomcat下运行两个系统? 通过域名访问从session中得不到信息,但通过ip地址就可以,有遇到过的么 JSP怎样配合Velocity 模板引擎动态生成HTML? struts2标签相关的问题? java问题,在函数体内执行的过程中,有两条语句直接跳过,为什么? 求助??谢谢了 谁能给份梅花雪的树型控件?
login.jsp
<%@ page contentType="text/html;charset=GB2312" language="java" %>
<head>
<META http-equiv=Content-Type content="text/html; charset=GB2312">
<style>
span{
color:red;
font-size:12px;
text-indent:2em;
}
</style>
</head>
<script language="javascript">
var XMLHttpReq = false;
//创建XMLHttpRequest对象
function createXMLHttpRequest() {
if(window.XMLHttpRequest) { //Mozilla 浏览器
XMLHttpReq = new XMLHttpRequest();
}
else if (window.ActiveXObject) { // IE浏览器
try {
XMLHttpReq = new ActiveXObject("Msxml2.XMLHTTP");
} catch (e) {
try {
XMLHttpReq = new ActiveXObject("Microsoft.XMLHTTP");
} catch (e) {}
}
}
}
//发送请求函数
function sendRequest(url) {
createXMLHttpRequest();
XMLHttpReq.open("GET", url, true);
XMLHttpReq.onreadystatechange = processResponse;//指定响应函数
XMLHttpReq.send(null); // 发送请求
}
// 处理返回信息函数
function processResponse() {
if (XMLHttpReq.readyState == 4) { // 判断对象状态
if (XMLHttpReq.status == 200) { // 信息已经成功返回,开始处理信息
var res=XMLHttpReq.responseXML.getElementsByTagName("res")[0].firstChild.data;
document.getElementById("cn").innerHTML=res;
}
}
}
// 身份验证函数
function checkUsername() {
var username=document.getElementById("username").value;
var url="CheckUsername?username="+ username;
sendRequest(url);
}</script><body vLink="#006666" link="#003366" bgColor="#E0F0F8">
<form action="" method="post" name="form">
用户名: <input size="15" type="text" name="username"onblur="checkUsername()" onkeypress="checkUsername()" onkeyup="checkUsername()" onkeydown="checkUsername()" />
<span id="cn"></span><p>
密 码: <input type="password" size="15" name="psw"><p>
<input type="button" value="登录" onclick="checkUsername()" >
</form>CheckUsername.javapackage com.sum;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class CheckUsername extends HttpServlet {
public void init(ServletConfig config) throws ServletException {
}
/*
* 处理<GET> 请求方法.
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//设置接收信息的字符集
request.setCharacterEncoding("UTF-8");
//接收浏览器端提交的信息
String username = request.getParameter("username");
//设置输出信息的格式及字符集
response.setContentType("text/xml; charset=UTF-8");
response.setHeader("Cache-Control", "no-cache");
//创建输出流对象
PrintWriter out = response.getWriter();
//依据验证结果输出不同的数据信息
out.println("<response>");
if(username.equals("jenny")){
out.println("<res>" + "热烈的欢迎您!" + "</res>");
}else{
out.println("<res>" + "对不起,登录失败!" + "</res>");
}
out.println("</response>");
out.close();
}
/*
* 处理<POST> 请求方法.
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}