java - Username and password validation from database to jsp view page -

if username , password retrieved database incorrect show error on jsp page instead of re-directing page.

right showing message validation servlet if username , passwords invalid. how show message on front end using javascript or anyother tool jsp view?

below login form:

<form id="loginform" class="form-horizontal" name="myform" method="post" action="validateloginservlet2.do" onsubmit="return validatelogin()">     <input type="text" class="form-control" name="uname" placeholder="username">                                             <input id="login-password" type="password" class="form-control" name="pwd" placeholder="password">     <input type="submit" value="login" href="#" class="btn btn-success" /> </form> 

and validate login servlet:

protected void dopost(httpservletrequest request, httpservletresponse response)             throws servletexception, ioexception { //        processrequest(request, response);         printwriter out = response.getwriter();          string username = request.getparameter("uname");         string password = request.getparameter("pwd");         system.out.println(username);         system.out.println(password);          try         {             connection con = oracledbconnection.getconnection();             preparedstatement statement = con.preparestatement("select firstname, password registration firstname =? , password=?");             statement.setstring(1, username);             statement.setstring(2, password);             resultset result = statement.executequery();             if(result.next()){                 response.sendredirect("loginsuccessful.jsp");             }else{                 out.println("username , password incorrect");             }         }catch(exception e){             system.out.println("db related error");             e.printstacktrace();         }        } 

you can use <span> element show error message servlet request, here's jsp page:

<form id="loginform" class="form-horizontal" name="myform" method="post" action="validateloginservlet2.do" onsubmit="return validatelogin()">     <input type="text" class="form-control" name="uname" placeholder="username">                                             <input id="login-password" type="password" class="form-control" name="pwd" placeholder="password">     <input type="submit" value="login" href="#" class="btn btn-success" />     <span style="color:red;">${errmsg}</span> </form> 

and in servlet set error message in else statment this:

if(result.next()) {     response.sendredirect("loginsuccessful.jsp"); }else{     request.setattribute("errmsg", "username , password incorrect");     // following keep in login page     requestdispatcher rd = request.getrequestdispatcher("/login.jsp");     rd.forward(request, response);  } 

and prevent showing same error next login in if block login successful can reset errmsg this:

request.setattribute("errmsg", "");