servlet:
public class Login extends HttpServlet {
/**
*
*/
private static final long serialVersionUID = 1L; public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException { this.doPost(request, response);
} public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException { response.setContentType("text/html");
PrintWriter out = response.getWriter();
String logined[]={"admin","lihai"};
String name=request.getParameter("username");
String responseContext="true";
for(int i=0;i<logined.length;i++){
if(name.equals(logined[i]))
responseContext="false";
}
request.setAttribute("login",responseContext);
out.flush();
out.close();
}}
index.jsp
<script type="text/javascript">
var xmlHttp;
function createXMLHttpRequest(){
if(window.ActiveXObject()){
xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
}
else if(window.XMLHttpRequest){
xmlHttp=new XMLHttpRequest();
}
}
function begincheck(){
var name=document.all.username.value;
if(name==""){
alert("please your name");
return;
}
createXMLHttpRequest();
XmlHttp.onreadystatechange=processor;
xmlHttp.open("GET","/AJAX/servlet/Login?username="+name);
xmlHttp.send(null);
}
function processor(){
if(xmlHttp.readyState==4){
if(xml=Http.status==200){
responseContext=xmlHttp.responseText;
if(responseContext.indexOf("true")!=-1){
alert("<span style='color:red'>恭喜你注册成功</span>");
}
else{
alert("<span style='color:red'>注册失败</span>");
}
}
}
}
</script>
</head>
<body><form method="post" action="/AJAX/servlet/Login" name="form1">
<p><input type="text" name="username"></p>
<p><input type="submit" value="注册"></p></form>
</body>
我运行没有任何结果,不知道错在哪里,希望各位大哥大姐帮小弟一个蛮
public class Login extends HttpServlet {
/**
*
*/
private static final long serialVersionUID = 1L; public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException { this.doPost(request, response);
} public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException { response.setContentType("text/html");
PrintWriter out = response.getWriter();
String logined[]={"admin","lihai"};
String name=request.getParameter("username");
String responseContext="true";
for(int i=0;i<logined.length;i++){
if(name.equals(logined[i]))
responseContext="false";
}
request.setAttribute("login",responseContext);
out.flush();
out.close();
}}
index.jsp
<script type="text/javascript">
var xmlHttp;
function createXMLHttpRequest(){
if(window.ActiveXObject()){
xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
}
else if(window.XMLHttpRequest){
xmlHttp=new XMLHttpRequest();
}
}
function begincheck(){
var name=document.all.username.value;
if(name==""){
alert("please your name");
return;
}
createXMLHttpRequest();
XmlHttp.onreadystatechange=processor;
xmlHttp.open("GET","/AJAX/servlet/Login?username="+name);
xmlHttp.send(null);
}
function processor(){
if(xmlHttp.readyState==4){
if(xml=Http.status==200){
responseContext=xmlHttp.responseText;
if(responseContext.indexOf("true")!=-1){
alert("<span style='color:red'>恭喜你注册成功</span>");
}
else{
alert("<span style='color:red'>注册失败</span>");
}
}
}
}
</script>
</head>
<body><form method="post" action="/AJAX/servlet/Login" name="form1">
<p><input type="text" name="username"></p>
<p><input type="submit" value="注册"></p></form>
</body>
我运行没有任何结果,不知道错在哪里,希望各位大哥大姐帮小弟一个蛮
function getHTTPObject(){
var xmlhttp = false;
if(window.XMLHttpRequest){
xmlhttp = new XMLHttpRequest();
if(xmlhttp.overrideMimeType){
xmlhttp.overrideMimeType('text/xml');
}
}
else{
try{
xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
}catch(e){
try{
xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
}catch(E){
xmlhttp = false;
}
}
}
return xmlhttp;
}
function getUsers(){
var url = "***Action.do?proc=getMessenges";// proc 为你自己定义的
url+= "&username="+你页面输入的username//document.getElementById(userName).value;
http.open("POST",url,true);
http.onreadystatechange = responseMessenges;
http.send(null);
}
function responseMessenges(){
if(http.readyState == 4){
if(http.status == 200){
var info = http.responseText;//这是action的返回值
//在这里做其他的操作 比如你有用户返回1 没有就2 那就你的时候就alert提示信息
}
else{
alert("您所请求的页面发生异常,可能会影响您浏览该页的信息!");
}
}
}
</script> ----------
输入用户名的框里你可以用
<input type="text" name="userName" onblur="getUsers()">
----------
public ActionForward getMessenges(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response)
throws Exception {
String username= request.getParameter("username");
username= new String(username.getBytes("ISO-8859-1"), "GBK");//解决中文乱码问题
//这里你就可以用username去判断用户名有没有已经存在了
response.setContentType("text/html");
response.setCharacterEncoding("UTF-8");
response.getWriter().print("你要返回页面的东西")
return mapping.findForward("");
}
xmlHttp.open("GET","/AJAX/servlet/Login?username="+name);
你的servlet的配置文件看看
<description>This is the description of my J2EE component</description>
<display-name>This is the display name of my J2EE component</display-name>
<servlet-name>Login</servlet-name>
<servlet-class>com.servlet.Login</servlet-class>
</servlet> <servlet-mapping>
<servlet-name>Login</servlet-name>
<url-pattern>/servlet/Login</url-pattern>
</servlet-mapping>
<body> <form method="post" action="/AJAX/servlet/Login" name="form1">
<p> <input type="text" name="username" onblur="begincheck();"> </p>
<p> <input type="submit" value="注册"> </p> </form>
</body>