摘要：序本文從里頭摘出訪問的源碼，展示一下怎么用去訪問。其中指定要不要檢驗，如果不校驗，則是使用小結使用不去驗證，但是可能存在風險構造

本文從spring cloud netflix zuul里頭摘出httpclient訪問https/http的源碼，展示一下怎么用httpclient去訪問https。

protected PoolingHttpClientConnectionManager newConnectionManager(boolean sslHostnameValidationEnabled) {
        try {
            final SSLContext sslContext = SSLContext.getInstance("SSL");
            sslContext.init(null, new TrustManager[] { new X509TrustManager() {
                @Override
                public void checkClientTrusted(X509Certificate[] x509Certificates,
                                               String s) throws CertificateException {
                }

                @Override
                public void checkServerTrusted(X509Certificate[] x509Certificates,
                                               String s) throws CertificateException {
                }

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

            RegistryBuilder registryBuilder = RegistryBuilder
                    . create()
                    .register("http", PlainConnectionSocketFactory.INSTANCE);
            if (sslHostnameValidationEnabled) {
                registryBuilder.register("https",
                        new SSLConnectionSocketFactory(sslContext));
            }
            else {
                registryBuilder.register("https", new SSLConnectionSocketFactory(
                        sslContext, NoopHostnameVerifier.INSTANCE));
            }
            final Registry registry = registryBuilder.build();

            PoolingHttpClientConnectionManager connectionManager = new PoolingHttpClientConnectionManager(registry);
            connectionManager
                    .setMaxTotal(200);
            connectionManager.setDefaultMaxPerRoute(20);
            return connectionManager;
        }
        catch (Exception ex) {
            throw new RuntimeException(ex);
        }
    }

其中sslHostnameValidationEnabled指定要不要檢驗ssl，如果不校驗，則是使用NoopHostnameVerifier

@Contract(threading = ThreadingBehavior.IMMUTABLE)
public class NoopHostnameVerifier implements HostnameVerifier {

    public static final NoopHostnameVerifier INSTANCE = new NoopHostnameVerifier();

    @Override
    public boolean verify(final String s, final SSLSession sslSession) {
        return true;
    }

    @Override
    public final String toString() {
        return "NO_OP";
    }

}

final RequestConfig requestConfig = RequestConfig.custom()
                .setSocketTimeout(60000)
                .setConnectTimeout(60000)
                .setCookieSpec(CookieSpecs.IGNORE_COOKIES).build();
        HttpClientBuilder httpClientBuilder = HttpClients.custom();
        httpClientBuilder.setSSLHostnameVerifier(NoopHostnameVerifier.INSTANCE);
        HttpClient httpclient = httpClientBuilder.setConnectionManager(newConnectionManager(false))
                .useSystemProperties().setDefaultRequestConfig(requestConfig)
                .setRetryHandler(new DefaultHttpRequestRetryHandler(0, false))
                .setRedirectStrategy(new RedirectStrategy() {
                    @Override
                    public boolean isRedirected(HttpRequest request,
                                                HttpResponse response, HttpContext context)
                            throws ProtocolException {
                        return false;
                    }

                    @Override
                    public HttpUriRequest getRedirect(HttpRequest request,
                                                      HttpResponse response, HttpContext context)
                            throws ProtocolException {
                        return null;
                    }
                }).build();

HttpRequest httpRequest = new BasicHttpRequest("GET","/api/data");
        HttpHost httpHost = new HttpHost("demo.com.cn",-1,"https");
        try{
            return httpClient.execute(httpHost, httpRequest);
//            System.out.println(response.getEntity().getContent());
        }catch (Exception e){
            e.printStackTrace();
        }

使用NoopHostnameVerifier不去驗證ssl，但是可能存在風險

構造X509TrustManager