Ajax js 使用Ajax检测用户名是否存在

发布时间：2020-12-15 21:04:07 所属栏目：百科来源：网络整理

导读：jsp页面: Js代码 scripttype= "text/javascript" language= "javascript" var xmlHttp= false ; try { xmlHttp= new ActiveXObject( "Msxml2.XMLHTTP" ); } catch (e){ try { xmlHttp= new ActiveXObject( "Microsoft.XMLHTTP" ); } catch (e2){ xmlHttp= fal

jsp页面:

Js代码

<scripttype="text/javascript"language="javascript">
varxmlHttp=false;
try{
xmlHttp=newActiveXObject("Msxml2.XMLHTTP");
}catch(e){
try{
xmlHttp=newActiveXObject("Microsoft.XMLHTTP");
}catch(e2){
xmlHttp=false;
}
}
if(!xmlHttp&&typeofXMLHttpRequest!='undefined'){
xmlHttp=newXMLHttpRequest();
}
//检测用户名是否存在
functioncallServerCheckUname(){
//通过GET方法请求，将请求封装在URL中
varuname=document.getElementById("u_name").value;
xmlHttp.open("POST",'CheckUname?u_name='+uname);
//设置服务器响应的处理方法
xmlHttp.onreadystatechange=updatePageCheckUname;
//发送请求
xmlHttp.send(null);
}
functionupdatePageCheckUname(){
if(xmlHttp.readyState==4){
varresponse=xmlHttp.responseText;
if(response>=1){
alert("用户名已存在!");
}else{
alert("可注册!");
}
}
}
</script>

<script type="text/javascript" language="javascript">
		var xmlHttp = false;
		try {
		    xmlHttp = new ActiveXObject("Msxml2.XMLHTTP");
		} catch (e) {
		    try {
		        xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
		    } catch (e2) {
		        xmlHttp = false;
		    }
		}
		if (!xmlHttp && typeof XMLHttpRequest != 'undefined') {
		    xmlHttp = new XMLHttpRequest();
		}
		
		//检测用户名是否存在
		function callServerCheckUname() {
		    //通过GET方法请求，将请求封装在URL中
		    var uname = document.getElementById("u_name").value;
		    xmlHttp.open("POST",'CheckUname?u_name='+uname);
		    //设置服务器响应的处理方法
		    xmlHttp.onreadystatechange = updatePageCheckUname;
		    // 发送请求
		    xmlHttp.send(null);
		}
		function updatePageCheckUname() {
		    if (xmlHttp.readyState == 4) {
		        var response = xmlHttp.responseText;
		        if(response >= 1){
		    	    alert("用户名已存在!");
		        }else{
		    	    alert("可注册!");
		        }
		    }
		}
		</script>

web.xml配置文件:

Xml代码

<servlet>
<servlet-name>CheckUname</servlet-name>
<servlet-class>servlet.AjaxCheckUname</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>CheckUname</servlet-name>
<url-pattern>/CheckUname</url-pattern>
</servlet-mapping>

<servlet>
    <servlet-name>CheckUname</servlet-name>
    <servlet-class>servlet.AjaxCheckUname</servlet-class>
  </servlet>
<servlet-mapping>
    <servlet-name>CheckUname</servlet-name>
    <url-pattern>/CheckUname</url-pattern>
  </servlet-mapping>

servlet页面:

Java代码

publicvoiddoPost(HttpServletRequestrequest,HttpServletResponseresponse)
throwsServletException,IOException{
response.setContentType("text/html;charset=GB2312");
PrintWriterout=response.getWriter();
try{
Stringuname=request.getParameter("u_name");
RegistDAOImplregDao=newRegistDAOImpl();
out.print(regDao.checkUname(uname));
}catch(Exceptione){
}
out.flush();
out.close();
}

public void doPost(HttpServletRequest request,HttpServletResponse response)
			throws ServletException,IOException {
		response.setContentType("text/html;charset=GB2312");
		PrintWriter out = response.getWriter();
		try {
			String uname = request.getParameter("u_name");
			RegistDAOImpl regDao = new RegistDAOImpl();
			out.print(regDao.checkUname(uname)) ;
		} catch (Exception e) {
		}
		out.flush();
		out.close();
	}

DAO实现类:

Java代码

publicintcheckUname(Stringuname){
Connectionconn=null;
PreparedStatementpstm=null;
ResultSetrs=null;
intsuccess=0;
Stringsql="selectu_namefromu_infowhereu_name='"+uname+"'oru_mobtel='"+uname+"'oru_email='"+uname+"'";
try{
conn=getConnection();
pstm=conn.prepareStatement(sql);
rs=pstm.executeQuery(sql);
if(rs.next()){
success=1;
}
returnsuccess;
}catch(Exceptione){
e.printStackTrace();
}finally{
try{
conn.close();
}catch(Exceptione){
e.printStackTrace();
}
}
returnsuccess;
}

（编辑：李大同）

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