利用ajax检测用户名是否存在_tomcat和ajax判断用户名是否存在-优快云博客

本文链接：https://blog.youkuaiyun.com/yvan2008/article/details/4309648

本文介绍了一个基于Struts框架实现的用户名检测功能，通过Ajax技术实时检查用户名是否存在或包含非法字符，并展示了如何配置Struts及使用不同技术栈实现相同功能。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

这是一个很常见的检测用户名是否存在的功能

这里用的是struts

<%@ page contentType="text/html; charset=GBK" %> <html> <head> <title> ajax </title> </head> <body bgcolor="#ffffff"> <h1> <input name="username" type="text" maxlength="20" /> <input id="chk-name-btn" type="button" value="检测帐号" onclick="testName('<%=request.getContextPath()%>')" /> <div id="view_name"></div> </h1> </body> </html> <mce:script language="javascript"></mce:script> 这个jsp页面并没有取得用户名，就是演示一下。还有<div>可以换span，具体作用问美工吧。接受ajax请求的action。 import org.apache.struts.action.*; import javax.servlet.http.*; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.io.PrintWriter; /** * <p>Title:AjaxAction </p> */ public class AjaxAction extends Action { public ActionForward execute(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws Exception { PrintWriter out = response.getWriter(); out.print(1);//ajax取得都是字符的输出。如果数据量大的话，还可以用xml来发送和接受 return null; } } struts-config.xml <action type="test.whw.upload.AjaxAction" validate="false" scope="request" path="/ajax"/> －－－－－－－－－－－－－－－－－－－－－－－－－－－－如果是servlet web.xml <servlet> <servlet-name>AjaxServlet </servlet-name> <servlet-class>servlet.AjaxServlet </servlet-class> </servlet> <servlet-mapping> <servlet-name>AjaxServlet </servlet-name> <url-pattern>/AjaxServlet .servlet</url-pattern> </servlet-mapping> AjaxServlet.java import java.io.IOException; import java.io.PrintWriter; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class AjaxServlet extends HttpServlet { Logger log = Logger.getLogger(this.getClass()); public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException,IOException { response.setContentType("text/xml; charset=GBK"); PrintWriter out = response.getWriter(); out.print(2); } } //Process the HTTP Post request public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } //Process the HTTP Put request public void doPut(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { } //Process the HTTP Delete request public void doDelete(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { } //Clean up resources public void destroy() { } } －－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－如果是webwork xwork.xml <action name="ajax" class="com.whw.upload.action.webwork.AjaxAction" method="ajax"/> AjaxAction.java import java.io.PrintWriter; public class AjexAlbumAction extends ActionSupport implements Action{ public void ajax()throws IOException { PrintWriter pw = ServletActionContext.getResponse().getWriter(); ServletActionContext.getResponse().setContentType("text/html;charset=GBK"); pw.print(1); pw.close(); } }

本例子在winXPsp2、JB9、Eclipse3，j2sdk1.4.1 、Tomcat5、Tomcat4.1都能运行