如何使用apache java HttpClient 4.5从连接请求中检索响应头？

Question

我使用http代理通过CloseableHttpClient连接https网站。首先发送连接请求，因为它必须进行隧道连接。将发送响应头，我需要检索它们。结果将存储在变量中，稍后使用。

在HttpClient 4.2上，我可以使用HttpResponseInterceptor实现它：

final DefaultHttpClient httpClient = new DefaultHttpClient();
//configure proxy


httpclient.addResponseInterceptor(new HttpResponseInterceptor() {
    public void process(HttpResponse httpResponse, HttpContext httpContext) throws HttpException, IOException {
        final Header[] headers = httpResponse.getAllHeaders();

        //store headers
    }
});

但当我使用HttpClient 4.5时，我的响应拦截器从未在连接请求上被调用。它在GET或POST请求时直接跳转：

 final CloseableHttpClient httpClient = HttpClients.custom()
                .setProxy(new HttpHost(proxyHost, proxyPort, "http"))
                .addInterceptorFirst(new HttpResponseInterceptor() {
                    public void process(HttpResponse httpResponse, HttpContext httpContext) throws HttpException, IOException {
                        final Header[] headers = httpResponse.getAllHeaders();

                        //store headers
                    }
                }).build();

方法setInterceptorLast（）和setHttpProcencer（）的结果相同。提前感谢：）

Answer 1

您需要一个自定义的HttpClientBuilder类，以便能够将自定义协议侦听器添加到用于执行连接方法的HTTP协议处理器。

HttpClient 4.5它不漂亮，但它会完成工作：

HttpClientBuilder builder = new HttpClientBuilder() {

    @Override
    protected ClientExecChain createMainExec(
            HttpRequestExecutor requestExec,
            HttpClientConnectionManager connManager,
            ConnectionReuseStrategy reuseStrategy,
            ConnectionKeepAliveStrategy keepAliveStrategy,
            HttpProcessor proxyHttpProcessor,
            AuthenticationStrategy targetAuthStrategy,
            AuthenticationStrategy proxyAuthStrategy,
            UserTokenHandler userTokenHandler) {

        final ImmutableHttpProcessor myProxyHttpProcessor = new ImmutableHttpProcessor(
                Arrays.asList(new RequestTargetHost()),
                Arrays.asList(new HttpResponseInterceptor() {

                    @Override
                    public void process(
                            HttpResponse response,
                            HttpContext context) throws HttpException, IOException {

                    }
                })
        );

        return super.createMainExec(requestExec, connManager, reuseStrategy, keepAliveStrategy,
                myProxyHttpProcessor, targetAuthStrategy, proxyAuthStrategy, userTokenHandler);
    }

};

HttpClient 5.0经典：

CloseableHttpClient httpClient = HttpClientBuilder.create()
        .replaceExecInterceptor(ChainElement.CONNECT.name(),
                new ConnectExec(
                        DefaultConnectionReuseStrategy.INSTANCE,
                        new DefaultHttpProcessor(new RequestTargetHost()),
                        DefaultAuthenticationStrategy.INSTANCE))
        .build();