Question

我有一个连接到服务器的应用程序。我设置了超时，将设备与Internet断开连接并尝试执行post请求以查看是否已调用超时，但连接始终等待。这是我的代码：

private static final int TIMEOUT_OPS = 3000 ;
private HttpClient mHttpClient;

public String sendToken(String token) throws IOException, AuthenticationException {
    JSONArray jsonData = new JSONArray();
    jsonData.put(token);

    final HttpPost post = prepareJSONRequest(jsonData.toString(), SEND_TOKEN_METHOD);
    HttpClient httpClient = getConnection();
    Log.i(TAG, "Sending request");
    final HttpResponse resp;
    try{
        resp = httpClient.execute(post);
    }catch(Exception e){
        e.printStackTrace();
        return null;
    }
    Log.i(TAG, "Got response");
    ...
}

private HttpPost prepareJSONRequest(String rest_data, String method) throws AssertionError {
    AbstractHttpEntity entity = null;
    try {
        final ArrayList<NameValuePair> params = new ArrayList<NameValuePair>();
        params.add(new BasicNameValuePair(KEY_PARAM_METHOD, method));
        params.add(new BasicNameValuePair(KEY_PARAM_INPUT_TYPE, JSON));
        params.add(new BasicNameValuePair(KEY_PARAM_RESPONSE_TYPE, JSON));
        params.add(new BasicNameValuePair("rest_data", rest_data));
        entity = new UrlEncodedFormEntity(params, HTTP.UTF_8);
        final HttpPost post = new HttpPost(mServer);
        post.addHeader(entity.getContentType());
        post.setEntity(entity);
        return post;

    } catch (final UnsupportedEncodingException e) {
        // this should never happen.
        throw new AssertionError(e);
    }
}

private HttpClient getConnection() {
    if (mHttpClient == null) {
        // registers schemes for both http and https
        HttpParams params = new BasicHttpParams();
        HttpProtocolParams.setVersion(params, HttpVersion.HTTP_1_1);
        HttpProtocolParams.setContentCharset(params, HTTP.UTF_8);
        HttpProtocolParams.setUseExpectContinue(params, false);
        HttpConnectionParams.setConnectionTimeout(params, TIMEOUT_OPS);
        HttpConnectionParams.setSoTimeout(params, TIMEOUT_OPS);
        ConnManagerParams.setTimeout(params, TIMEOUT_OPS);
        SchemeRegistry registry = new SchemeRegistry();
        registry.register(new Scheme("http", PlainSocketFactory.getSocketFactory(), 80));
        final SSLSocketFactory sslSocketFactory = SSLSocketFactory.getSocketFactory();
        sslSocketFactory.setHostnameVerifier(SSLSocketFactory.BROWSER_COMPATIBLE_HOSTNAME_VERIFIER);
        if (!mNoCertValidation)
            registry.register(new Scheme("https", sslSocketFactory, 443));
        else
            registry.register(new Scheme("https", new EasySSLSocketFactory(), 443));
        ThreadSafeClientConnManager manager = new ThreadSafeClientConnManager(params, registry);
        mHttpClient = new DefaultHttpClient(manager, params);

    }
    return mHttpClient;
}

如果我执行此代码，我的日志显示“发送请求”，但不会打印异常或“得到响应”。为什么不起作用？

Answer 1

如果您没有Internet，DNS请求将失败，但您无法控制DNS超时。最终你应该得到一个UnknownHostException，但这可能需要几分钟。在这种情况下，最好的办法是在发出HTTP请求的同时在单独的线程中启动计时器。如果计时器在HTTP请求完成之前关闭，则可以中止HTTP请求。

Android：连接超时不起作用（连接等待永远）

1 个答案: