HttpClient的NoHttpResponse问题

   调用第三方接口时会报NoHttpResponse异常，原因是上次的连接已经断掉了，但是客户端并未知道，复用上次连接就报错了，所以要解决这个问题，就是要校验上次链接是否断掉了

 1. httpClient已经给我们实现了这个，setRetryHandler

public static RestTemplate builRestTemplate() {
        SSLConnectionSocketFactory sf = null;
        try {
            sf = new SSLConnectionSocketFactory(new SSLContextBuilder().loadTrustMaterial(null, new TrustSelfSignedStrategy()).build(), new NoopHostnameVerifier());
        } catch (NoSuchAlgorithmException | KeyManagementException | KeyStoreException e) {
            logger.error("SSL related failure: {} ", e.getMessage());
            throw new CloudChefException("SSL error");
        }

        CloseableHttpClient httpClient = HttpClients.custom().setSSLSocketFactory(sf).setRetryHandler((exception, executionCount, context) -> {
            if (executionCount > 3) { //重试3次，大于3次则结束
                logger.warn("Maximum tries reached for client http pool ");
                return false;
            }
            if (exception instanceof org.apache.http.NoHttpResponseException) { //如果是NoHttpResponseException则进行重试
                logger.warn("No response from server on " + executionCount + " call");
                return true;
            }
            return false;
        }).build();

        HttpComponentsClientHttpRequestFactory requestFactory = new HttpComponentsClientHttpRequestFactory();
        requestFactory.setHttpClient(httpClient);
        configureTimeout(requestFactory);
        return new RestTemplate(requestFactory);
    }

    private static void configureTimeout(HttpComponentsClientHttpRequestFactory factory) {
        //默认http request超时设置
        factory.setReadTimeout(120_1000);
        factory.setConnectTimeout(15_1000);
        factory.setConnectionRequestTimeout(15_1000);
    }

2.或者使用 DefaultHttpRequestRetryHandler

HttpClientBuilder clientBuilder = HttpClients.custom();
clientBuilder.setRetryHandler(new DefaultHttpRequestRetryHandler(3, true));

对于这个问题的分析有一个不错的博客，写的不错：https://czjxy881.github.io/java,nginx/%E8%AE%B0HttpClient%E7%9A%84NoHttpResponse%E9%97%AE%E9%A2%98/　

对于解决方案，来自于：https://stackoverflow.com/questions/10570672/get-nohttpresponseexception-for-load-testing/10680629#10680629