SOCK is a TCP/IP level proxy protocol, not HTTP. It is not supported by HttpClient out of the box.
One can customize HttpClient to establish connections via a SOCKS proxy by using a custom connection socket factory
EDIT: changes to SSL instead of plain sockets
Registry<ConnectionSocketFactory> reg = RegistryBuilder.<ConnectionSocketFactory>create() .register("http", PlainConnectionSocketFactory.INSTANCE) .register("https", new MyConnectionSocketFactory(SSLContexts.createSystemDefault())) .build(); PoolingHttpClientConnectionManager cm = new PoolingHttpClientConnectionManager(reg); CloseableHttpClient httpclient = HttpClients.custom() .setConnectionManager(cm) .build(); try { InetSocketAddress socksaddr = new InetSocketAddress("mysockshost", 1234); HttpClientContext context = HttpClientContext.create(); context.setAttribute("socks.address", socksaddr); HttpHost target = new HttpHost("localhost", 80, "http"); HttpGet request = new HttpGet("/"); System.out.println("Executing request " + request + " to " + target + " via SOCKS proxy " + socksaddr); CloseableHttpResponse response = httpclient.execute(target, request, context); try { System.out.println("----------------------------------------"); System.out.println(response.getStatusLine()); EntityUtils.consume(response.getEntity()); } finally { response.close(); } } finally { httpclient.close(); }
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static class MyConnectionSocketFactory extends SSLConnectionSocketFactory { public MyConnectionSocketFactory(final SSLContext sslContext) { super(sslContext); } @Override public Socket createSocket(final HttpContext context) throws IOException { InetSocketAddress socksaddr = (InetSocketAddress) context.getAttribute("socks.address"); Proxy proxy = new Proxy(Proxy.Type.SOCKS, socksaddr); return new Socket(proxy); } }