java.net.SocketException: Connection reset异常的几种原因分析和解决方法

public class HttpClientFactory {
    private static CloseableHttpClient client;

    public static HttpClient getHttpsClient() throws Exception {

        if (client != null) {
            return client;
        }
        SSLContext sslcontext = SSLContexts.custom().useSSL().build();
        sslcontext.init(null, new X509TrustManager[]{new HttpsTrustManager()}, new SecureRandom());
        SSLConnectionSocketFactory factory = new SSLConnectionSocketFactory(sslcontext,new String[] { "SSLv3", "TLSv1", "TLSv1.1", "TLSv1.2" }, null,
                SSLConnectionSocketFactory.ALLOW_ALL_HOSTNAME_VERIFIER);
        client = HttpClients.custom().setSSLSocketFactory(factory).build();

        return client;
    }

    public static void releaseInstance() {
        client = null;
    }
}

public class HttpsTrustManager implements X509TrustManager {

    @Override
    public void checkClientTrusted(X509Certificate[] arg0, String arg1)
            throws CertificateException {
        // TODO Auto-generated method stub

    }

    @Override
    public void checkServerTrusted(X509Certificate[] arg0, String arg1)
            throws CertificateException {
        // TODO Auto-generated method stub

    }

    @Override
    public X509Certificate[] getAcceptedIssuers() {
        return new X509Certificate[]{};
    }

}

  HttpClient httpClient = HttpClientFactory.getHttpsClient();
    HttpPost request = new HttpPost(requestUrl);
    request.setEntity(new StringEntity(gson.toJson(requestMap), "application/json", "UTF-8"));

    HttpResponse httpResponse = httpClient.execute(request);
    resultStr = EntityUtils.toString(httpResponse.getEntity(), "UTF-8");
    System.out.println(resultStr);
    httpResponse.getEntity().getContent().close();