ajax验证用户名是否存在
在网上看了不少关于验证用户名是否存在的代码,似乎总存在这样或者那样的问题,经过我机房测试我把已经成功了代码贴上来,以备以后之用;
先建立一个servlet: CheckUser 代码如下:
package https://www.360docs.net/doc/1412358524.html,shop.para;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import https://www.360docs.net/doc/1412358524.html,shop.dbimpl.DbUserInfoimpl;
public class CheckUser extends HttpServlet {
/**
*
*/
private static final long serialVersionUID = -9038308848332609445L;
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/xml;charset=GBK");
response.setHeader("Cache-Control", "no-cache");
String username = request.getParameter("username");
System.out.println(username);
DbUserInfoimpl dbUserInfoimpl = new DbUserInfoimpl();
boolean flag = dbUserInfoimpl.list(username);
String msg = "";
try{
if (!flag) {
msg = "用户名"+username+"已经存在";
}
else {
msg = "恭喜你,"+username+"可以使用";
}
System.out.println("msg"+msg);
}catch(Exception ex){
}
response.getWriter().println("");
response.getWriter().println("
response.getWriter().println("
response.getWriter().print(msg);
response.getWriter().println("
response.getWriter().println("
response.getWriter().close();
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// TODO Auto-generated method stub
doPost(request, response);
}
}
然后配置web.xml
再去jsp页面书写ajax代码
最后不要设置div哟: