我有发送摘要请求的restlet示例客户端程序。类似于此，我需要使用HttpClient API发送摘要请求的Java客户端程序。任何人都可以给我示例代码。提前感谢。

Reference reference = new Reference("http://localhost:8092/authenticate");
        Client client = new Client(Protocol.HTTP);
        Request request = new Request(Method.GET, reference);
        Response response = client.handle(request);
        System.out.println("response: "+response.getStatus());

        Form form = new Form();
        form.add("username", "rajesh");
        form.add("uri", reference.getPath());

        // Loop over the challengeRequest objects sent by the server.
        for (ChallengeRequest challengeRequest : response
                .getChallengeRequests()) {
            // Get the data from the server's response.
            if (ChallengeScheme.HTTP_DIGEST
                    .equals(challengeRequest.getScheme())) {
                Series<Parameter> params = challengeRequest.getParameters();
                form.add(params.getFirst("nonce"));
                form.add(params.getFirst("realm"));
                form.add(params.getFirst("domain"));
                form.add(params.getFirst("algorithm"));
                form.add(params.getFirst("qop"));
            }
        }

        // Compute the required data
        String a1 = Engine.getInstance().toMd5(
                "rajesh" + ":" + form.getFirstValue("realm") + ":" + "rajesh");
        String a2 = Engine.getInstance().toMd5(
                request.getMethod() + ":" + form.getFirstValue("uri"));
        form.add("response", Engine.getInstance().toMd5(
                a1 + ":" + form.getFirstValue("nonce") + ":" + a2));

        ChallengeResponse challengeResponse = new ChallengeResponse(
                ChallengeScheme.HTTP_DIGEST, "", "");
        challengeResponse.setCredentialComponents(form);

        // Send the completed request
        request.setChallengeResponse(challengeResponse);
        response = client.handle(request);

        // Should be 200.
        System.out.println(response.getStatus());