package com.gmail.brunodiazmartin5.rs.ws;

import java.io.IOException;
import java.util.List;
import java.util.StringTokenizer;
import javax.ws.rs.container.ContainerRequestContext;
import javax.ws.rs.container.ContainerRequestFilter;
import javax.ws.rs.core.Response;

import org.glassfish.jersey.internal.util.Base64;


public class SecuredFilter implements ContainerRequestFilter {

private static final String AUTHORIZATION_HEADER_KEY = "Authorization";
private static final String AUTHORIZATION_HEADER_PREFIX = "Basic";
private static final String SECURED_URL_PREFIX = "secured";

@Override
public void filter(ContainerRequestContext requestContext) throws IOException {
    if(requestContext.getUriInfo().getPath().contains(SECURED_URL_PREFIX)) {
        List<String> authHeader = requestContext.getHeaders().get(AUTHORIZATION_HEADER_KEY);

        if (authHeader != null && authHeader.size() > 0){
            String authToken = authHeader.get(0);
            authToken = authToken.replaceFirst(AUTHORIZATION_HEADER_PREFIX, "");
            String decodeString = Base64.decodeAsString(authToken);

            StringTokenizer tokenizer = new StringTokenizer(decodeString, ":");
            String username = tokenizer.nextToken();
            String password = tokenizer.nextToken();

            if ("admin".equals(username) && "admin".equals(password)) {
                return;
            }

            Response unauthorizedStatus = Response
                    .status(Response.Status.UNAUTHORIZED)
                    .encoding("No puedes acceder a recurso solicitado")
                    .build();

            requestContext.abortWith(unauthorizedStatus);

        }
    }
}

}

package com.gmail.brunodiazmartin5.rs.ws;

import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;

@Path("secured")
public class SecuredService {

@GET
@Path("message")
@Produces(MediaType.TEXT_PLAIN)
public String securedMethod(){
    return "Esta API necesita login";
}
}