Code to get a Java servlet to act as a proxy?

Question

I have two Java web applications that have a single servlet that gets mapped to a specific URL:

red.war/
    WEB-INF/classes
        com.me.myorg.red.RedServlet          


        

Answer 1

Since there is not yet an approved answer I try to write how I see the solution to this request use apache-http-commons library. In addition I suggest to add a flush on writer.

public class ProxyServlet extends HttpServlet {
@Override
public doGet(HttpServletRequest request, HttpServletResponse response) {
    String forwardingAddress;
    if(shouldBeRed(request))
        forwardingAddress = "http://red.example.com/doStuff";
    else
        forwardingAddress = "http://blue.example.com/doStuff";

    PrintWriter writer = response.getWriter();

    writer.write(getResponseFromBackend(forwardingAddress, request));
    **writer.flush();**
}

private String getResponseFromBackend(String addr, HttpServletRequest req) {
        HttpClient client = new HttpClient();
        HttpMethod method = new GetMethod(url);
        client.executeMethod(method);
        String body=method.getResponseBodyAsString();
        return body;

}

}