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How to send parameters from a request (servlet) to another request (servlet) in Java?

public String Home(HttpServletRequest request,
HttpServletResponse response, HttpSession session) {
String refer = request.getHeader("Referer");
request.setAttribute("refer", refer);
return "home/visit/editVisit";
}
public String Home2(HttpServletRequest request,
HttpServletResponse response, HttpSession session) {
String refer2 = request.getParameter("refer");
return "home/visit/addVisit";
}
In the first step, I get the function from one Controller to another Controller and since then the request changes in URL.
The new Controller page has several different functions.
I can catch the change there to know from which page I came by the line:
String refer = request.getHeader ("Refer");
But as I continue (by the buttons ...) to the next pages of the project. I don't have access to refer variable.
How can I be constantly available to a variable that would please and not only refer to a specific JSP?
I need quick help,
Thanks for every reply

spring load resources conditionally

I want to use JS to load another JS file from a server but i want to do it conditionally example if the userId sent by the request is in my database send back the file.
So i thought of creating an interceptor.
Is there a better way to do it because an interceptor would be an overkill?
<mvc:interceptors>
<mvc:interceptor>
<bean class="com.mycomp.webservice.UserInterceptor" />
</mvc:interceptor>
</mvc:interceptors>
public class UserInterceptor extends HandlerInterceptorAdapter {
#Autowired
UserService userService;
#Override
#Transactional
public boolean preHandle(HttpServletRequest request,
HttpServletResponse response, Object handler) throws Exception {
if(!userService.userPresent(request)){
return false;
}
else{
return true;
}
}
Edit: So i figured out that the question isn't that clear. the file i want to upload is part of the static resources so i don' want to just load it to the client, i want to cache it as well.
So i leave you with a link.
Edit 2: So this is what i ended up doing. under my mvc-resources config i created an interceptor to handle request for protected static resources.
<mvc:resources mapping="/static/**" location="/static/" />
<mvc:interceptors>
<mvc:interceptor>
<mvc:mapping path="/static/protected/**" />
<bean class="com.mycompany.interceptor.ProtectedResourcesInterceptor" />
</mvc:interceptor>
</mvc:interceptors>
public class ProtectedResourcesInterceptor extends HandlerInterceptorAdapter {
#Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
throws Exception {
if("your condition is true") {
System.out.println("Access Granted to protected resources");
return true;
}
return false;
}
}
The interceptor will handle requests to /static/protected and if conditions are right it will serve it. If anyone has a cleaner solution please share it.

Javascript function unable to make HTTP request

I have two different java projects and I need them to interact with each other. The first one named RESTfulWebServer is a dynamic web project which contains the basic HTTP GET PUT POST requests in a java class named UserServices. It just prints one line statements right now on console(output window in netbeans), so nothing complex.
The other project named ClientProject is also a dynamic web project which contains a simple jsp page containing javascript code. It is supposed to make call to the RESTfulWebServer project and print the output line on console(output window in netbeans) the same way the RESTfulWebServer project does when a simple GET request is made to it.
This is the part where the problem arises. When I run the ClientProject the javascript function is being called properly (as I checked by printing an alert message), but it is not making the DELETE HTTP request to the RESTfulWebServer as it is supposed to.
Both the codes are attached below:
RESTfulWebServer (UserServices.java)
package com.service.user;
import javax.ws.rs.*;
#Path("/user/service")
public class UserServices {
#GET
public void getUser()
{
System.out.println("Inside get user method");
}
#POST
public void updateUser()
{
System.out.println("Inside update user method");
}
#DELETE
public void deleteUser()
{
System.out.println("Inside DELETE user method");
}
}
ClientProject (clientfile.jsp)
<%#page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Update User</title>
<script>
function loadResponse()
{
var xmlhttp = new XMLHttpRequest();
xmlhttp.onreadystatechange = function()
{
if (xmlhttp.readyState === 4 && xmlhttp.status === 200)
{
document.getElementById("myDiv").innerHTML = xmlhttp.responseText;
}
};
xmlhttp.open("DELETE","http://localhost:8080/app/user/service",true);
xmlhttp.send();
}
</script>
</head>
<body>
<div id="myDiv">The response text would come here</div>
<button type ="button" onclick="loadResponse()">submit</button>
</body>
</html>
The clientfile is supposed to print on console "Inside DELETE user method" but nothing is showed on console after "Build successful" message
What am I doing wrong? Also I am making use of TomCat server and doing this in NetBeans and I have to work on this IDE solely for some reason (kindly do not suggest to move to any other IDE and check it) if there is any mistake in my code or anything else pleaseee mention it?

First of all starting with requesting URL http://localhost:8080/app/user/service
when it falls in class level annotation - there are three methods so which one to pick so, needed to provide method level annotations as well for better approach.
#Path("/user/service")
public class UserServices {
#Path("/getUser")
#GET
public void getUser() { System.out.println("Inside GET method"); }
#Path("/updateUser")
#POST
public void updateUser() { System.out.println("Inside UPDATE method"); }
#Path("/deleteUser")
#DELETE
public void deleteUser() { System.out.println("Inside DELETE method"); }
}
Now coming towards something important which is necessary to make project(RestWebServer) accept requests from another project(Client Projects/app) which is hosted on separate domain, i.e. CORS (Cross Origin Resource Sharing)
CORS, in a nutshell, is a security check implemented like when an application requests for resources from or make server calls to another domain, these requests get blocked by browsers. Moreover you are using XMLHttpRequest which forces same-origin policy i.e. request should generate from same domain where resources are residing so in order to make requests allow cross domain accessing we implement CORS Filter logic on server side to allow methods (P,G,P,D) to get executed.
So add a class like this in your WebService Project in package where UserServices class is:
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class CORSFilter implements Filter {
public CORSFilter() { }
public void init(FilterConfig fConfig) throws ServletException { }
public void destroy() { }
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
((HttpServletResponse)response).addHeader("Access-Control-Allow-Origin", "*");
((HttpServletResponse)response).addHeader("Access-Control-Allow-Methods", "POST, GET, PUT, OPTIONS, DELETE");
chain.doFilter(request, response);
}
}
Now time to use this Filter in web.xml
<web-app ....>
<filter>
<filter-name>CORSFilter</filter-name>
<filter-class><package name -must be complete>.CORSFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>CORSFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
</web-app>
clientFile.jsp
Now call method like this from view page with just method annotation added
xmlhttp.open('DELETE','http://localhost:8080/app/user/service/deleteUser',true);
Last thing you will have to make two server instances of Tomcat to deploy, name them Service and Client Server respectively for your convenience while making them. Let the Service one have all default config but you will have to change all three Port number for Client Server to avoid binding error. For this simply double click on server (Client) see Ports heading and change ports.
All done, it should run now, tested as well. Hope this will help you and other thread readers as well.

use spring security to tell ajax requests where the login page is

I have some url secured with spring (configured through xml). It works. However when I try to hit that endpoint with an ajax request I get a 302 (found) response. This redirects my ajax call to the login page (so I GET the html). However I'd like to get a 401 (unauthorized) response with the url of the login page available to the client application, so I can redirect the user there with javascript. This question seems to be the closest to what I want, but there's no example and it suggests changing the controller again. Is there no configuration in spring-security that will give me a 401 and a url (or some other sensible error message and the url of the login page)?

You can extend LoginUrlAuthenticationEntryPoint. Here is my one:
package hu.progos.springutils;
// imports omitted
public class AjaxAwareLoginUrlAuthenticationEntryPoint extends LoginUrlAuthenticationEntryPoint {
public void commence(final HttpServletRequest request, final HttpServletResponse response, final AuthenticationException authException) throws IOException, ServletException {
if ("XMLHttpRequest".equals(request.getHeader("X-Requested-With"))) {
response.sendError(HttpServletResponse.SC_FORBIDDEN, "Access Denied");
} else {
super.commence(request, response, authException);
}
}
}
Then configure spring to use your implementation:
<beans:bean id="authEntryPoint" class="hu.progos.springutils.AjaxAwareLoginUrlAuthenticationEntryPoint" scope="singleton>
<beans:property name="loginFormUrl" value="/login.html" />
</beans:bean>
<http entry-point-ref="authEntryPoint">
<!-- your settings here -->
</http>

There are a million ways to do this of course. But the short solution to your problem is this configuration snippet:
<bean id="customAuthEntryPoint" class="org.springframework.security.web.authentication.LoginUrlAuthenticationEntryPoint">
<property name="loginFormUrl" value="/your-custom-login" />
</bean>
I also take a step further and turn off the security auto-config so I can map the above entry point like so:
<security:http auto-config="false" entry-point-ref="customAuthEntryPoint">
...
...
</security:http>
I also override a bunch of spring security classes to get the security model to do exactly what I want. It's a slippery slope, but it's nice having the control once it works the way you want it to.

AJAX - Get response URL after redirect

I was wondering if there is a way to get the URL of the returned resource after a AJAX call in JavaScript?
I want to use this with a form, which is in "mysite.com/users/add.html". This is a Spring MVC controller. If the validation of the form fails the controller will return the "users/add" view, but if the validation is OK it will do a redirect to "mysite.com/users/index.html", using
return new ModelAndView(new RedirectView("/users/index.html"));
Is there a way in JavaScript to find the URL of the returned page?
Thanks,
Stian

Solved this by setting the response header "Location" in a Java Filter.
HttpServletRequest httpRequest = (HttpServletRequest) request;
HttpServletResponse httpResponse = (HttpServletResponse) response;
String path = httpRequest.getRequestURI();
httpResponse.setHeader("Location", path);
In JavaScript I could then use
XMLHttpRequest.getResponseHeader("Location")
Hopefully this won't cause any unforeseen problems. :P
If anyone else have an easier solution though I'd like to see it.