一个Ajax小示例

最新推荐文章于 2025-05-14 15:16:51 发布

最新推荐文章于 2025-05-14 15:16:51 发布 · 117 阅读

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#Ajax #SQL #Microsoft #HTML

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本文介绍了一种利用Ajax技术实现实时检测用户名是否已被注册的方法。通过客户端JavaScript与服务器端Java Servlet交互，实现了在用户输入时即时反馈用户名是否可用的功能。

	//------------Ajax处理是否相同名字-------------------
		var xmlHttpRequest;
    	//1. 创建XMLHttpRequest组件
		function createXmlHttpRequest(){
			if(window.ActiveXObject){
		    	return new ActiveXObject("Microsoft.XMLHTTP");
		  	}else if(window.XMLHttpRequest){
			    return new XMLHttpRequest();
			}
			if(xmlHttpRequest == null){
				alert("未能成功创建XMLHttpRequest组件!");
				return;
			}
		}
		function checkSameName(sameName){
			var url = "checkSameName?operatorId=" + sameName;
			// 1. 创建XMLHttpRequest组件
			xmlHttpRequest = createXmlHttpRequest();
			// 2. 设置回调函数
			xmlHttpRequest.onreadystatechange = myResponse;
			// 3. 初始化XMLHttpRequest组件
			xmlHttpRequest.open("GET",url,true);
			// 4. 发送请求
			xmlHttpRequest.send(null);
		}
		//--处理response------
		function myResponse(){
      		if(xmlHttpRequest.readyState == 4     
         		&& xmlHttpRequest.status == 200){
               var str = xmlHttpRequest.responseText;
      
               	if(str == 0){
               		document.getElementById("theSameName").innerHTML="<font color='red'>恭喜你,可以用此ID注册!</font>";
               	}else{
               		document.getElementById("theSameName").innerHTML="<font color='red'>对不起,此ID已经注册过了!</font>";
               	}
    	   }
		}

 <p>登录ID：<input type="text" name="operatorId" size="20" value= '${operatorId }' onBlur="return checkSameName(this.value)"/>例如:A00001</p>

public class CheckSameName extends HttpServlet {

	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		
		response.setContentType("text/html");
		PrintWriter out = response.getWriter();
		
		
		String id = request.getParameter("operatorId");
		if(id == null || id.equals("")){
			out.println("Not none!");
		}else{
			Connection conn = null;
			PreparedStatement pstmt = null;
			ResultSet rs = null;
			int isRegist = 0;
			String sql = "select operator_ID from TOperator where operator_ID = ?";
			try{
				conn = DbUtil.getConnection();
				pstmt = conn.prepareStatement(sql);
				pstmt.setString(1, id);
				rs = pstmt.executeQuery();
				if(rs.next()){
					isRegist = 1;
				}
			}catch(SQLException e){
				e.printStackTrace();
			}finally{
				new DbUtil().close(rs, pstmt, conn);
			}
			out.println(isRegist);
			out.flush();
			out.close();
		}
	}
}

这个,应该算是Ajax吧!