apache http client org.apache.http.NoHttpResponseException: 目标服务器未响应。

Question

我正在使用Apache Http Client测试我的Web服务。我已经在Jersey中编写了一个GET Web服务。该Web服务的URL为

http://localhost:8080/mobilestore/rest/sysgestockmobilews/getinventory?xml=dataString

调用此 Web 服务时，我必须编写以下方法来使用 URL：

public static void getInventory(String input)
        throws ClientProtocolException, IOException {

    System.out.println(input);
    String url = URL + "getinventory";
    HttpClient client = new DefaultHttpClient();

    List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(1);
    nameValuePairs.add(new BasicNameValuePair("xml", input));
    String paramString = URLEncodedUtils.format(nameValuePairs, "utf-8");
    url += "?" + paramString;
    System.out.println(url);
    HttpGet request = new HttpGet(url);
    HttpResponse response = client.execute(request);
    BufferedReader rd = new BufferedReader(new InputStreamReader(response
            .getEntity().getContent()));

    String line = "";
    while ((line = rd.readLine()) != null) {
        System.out.println(line);
    }

}

当我运行程序并将URL传递给该函数时，我在该行收到异常。

HttpResponse response = client.execute(request);

以下是异常信息

Aug 14, 2013 9:31:50 PM org.apache.http.impl.client.DefaultRequestDirector tryExecute
INFO: I/O exception (org.apache.http.NoHttpResponseException) caught when processing         request: The target server failed to respond
Aug 14, 2013 9:31:50 PM org.apache.http.impl.client.DefaultRequestDirector tryExecute
INFO: Retrying request
Aug 14, 2013 9:31:50 PM org.apache.http.impl.client.DefaultRequestDirector tryExecute
INFO: I/O exception (org.apache.http.NoHttpResponseException) caught when processing   request: The target server failed to respond
Aug 14, 2013 9:31:50 PM org.apache.http.impl.client.DefaultRequestDirector tryExecute
INFO: Retrying request
Aug 14, 2013 9:31:50 PM org.apache.http.impl.client.DefaultRequestDirector tryExecute
INFO: I/O exception (org.apache.http.NoHttpResponseException) caught when processing      request: The target server failed to respond
Aug 14, 2013 9:31:50 PM org.apache.http.impl.client.DefaultRequestDirector tryExecute
INFO: Retrying request
Exception in thread "main" org.apache.http.NoHttpResponseException: The target server failed to respond
at org.apache.http.impl.conn.DefaultHttpResponseParser.parseHead(DefaultHttpResponseParser.java:95)
at org.apache.http.impl.conn.DefaultHttpResponseParser.parseHead(DefaultHttpResponseParser.java:62)
at org.apache.http.impl.io.AbstractMessageParser.parse(AbstractMessageParser.java:254)
at org.apache.http.impl.AbstractHttpClientConnection.receiveResponseHeader(AbstractHttpClientConnection.java:289)
at org.apache.http.impl.conn.DefaultClientConnection.receiveResponseHeader(DefaultClientConnection.java:252)
at org.apache.http.impl.conn.ManagedClientConnectionImpl.receiveResponseHeader(ManagedClientConnectionImpl.java:191)
at org.apache.http.protocol.HttpRequestExecutor.doReceiveResponse(HttpRequestExecutor.java:300)
at org.apache.http.protocol.HttpRequestExecutor.execute(HttpRequestExecutor.java:127)
at org.apache.http.impl.client.DefaultRequestDirector.tryExecute(DefaultRequestDirector.java:715)
at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:520)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:906)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:805)
at    org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:784)
at com.tainosystems.http.client.TestWs.getInventory(TestWs.java:66)
at com.tainosystems.http.client.TestWs.main(TestWs.java:47)

现在，如果我使用WS网址并在任何浏览器中访问它，我会得到预期的结果，但是我想知道我的Apache HTTP客户端代码有什么问题。

现在，如果我使用WS的URL并在任何浏览器中访问它，我可以获得预期的结果，但我想知道我的Apache HTTP客户端代码存在什么问题。

- Waqas Ali

---

这里也曾经发布了完全相同的问题：https://dev59.com/PGkv5IYBdhLWcg3wfA4P - pls

Answer 1

我浏览了这里的链接并找到了这个答案：get NoHttpResponseException for load testing

这让我走上了正确的轨道。为了更新一下答案，这是使用当前的 http-client 4.5 API 的解决方案：

private final HttpComponentsClientHttpRequestFactory requestFactory = new HttpComponentsClientHttpRequestFactory(createHttpClient());

private CloseableHttpClient createHttpClient() {
    return HttpClients.custom().setRetryHandler((exception, executionCount, context) -> {
            if (executionCount > 3) {
                LOGGER.warn("Maximum tries reached for client http pool ");
                return false;
            }
            if (exception instanceof org.apache.http.NoHttpResponseException) {
                LOGGER.warn("No response from server on " + executionCount + " call");
                return true;
            }
            return false;
        }).build();
}

我还使用了spring-web，因此我将客户端作为RestTemplate工厂的参数，因为我想在RestTemplate中使用它。

- Ondrej Burkert