CORSFilter.java

package com.example;

import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
/**
 * Servlet Filter implementation class CORSFilter
 */
// Enable it for Servlet 3.x implementations
@WebFilter(asyncSupported = true, urlPatterns = { "/*" })
public class CORSFilter implements Filter {
 
    /**
     * Default constructor.
     */
    public CORSFilter() {
        // TODO Auto-generated constructor stub
    }
 
    /**
     * @see Filter#destroy()
     */
    public void destroy() {
        // TODO Auto-generated method stub
    }
 
    /**
     * @see Filter#doFilter(ServletRequest, ServletResponse, FilterChain)
     */
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain chain)
            throws IOException, ServletException { 
        HttpServletRequest request = (HttpServletRequest) servletRequest;
        System.out.println("CORSFilter HTTP Request: " + request.getMethod()); 
        // Authorize (allow) all domains to consume the content
        ((HttpServletResponse) servletResponse).addHeader("Access-Control-Allow-Origin", "*");
        ((HttpServletResponse) servletResponse).addHeader("content-type", "*");
        ((HttpServletResponse) servletResponse).addHeader("Access-Control-Allow-Headers", "*");
        ((HttpServletResponse) servletResponse).addHeader("Access-Control-Allow-Methods","GET, OPTIONS, HEAD, PUT, POST");
  HttpServletResponse resp = (HttpServletResponse) servletResponse; 
        // For HTTP OPTIONS verb/method reply with ACCEPTED status code -- per CORS handshake
        if (request.getMethod().equals("OPTIONS")) {
            resp.setStatus(HttpServletResponse.SC_ACCEPTED);
            return;
        }
        // pass the request along the filter chain
        chain.doFilter(request, servletResponse);
    }
 
    /**
     * @see Filter#init(FilterConfig)
     */
    public void init(FilterConfig fConfig) throws ServletException {
        // TODO Auto-generated method stub
    }
 
}