java——HttpClient 代理模式發送Http Https

在setProxy()方法中設置代理IP后可以將url中的域名換成這個代理IP。

http很簡單，但是https這樣會報錯。

問題：如何使用代理發送https請求？

客戶端發送https請求之前會先向這台服務器請求ssl證書，並在客服端對這個證書做一個校驗。

而使用代理IP時，實際上請求打到了這個代理IP上，而客戶端並不知道這件事，他仍然在等待url域名中所對應的ssl證書，而這代理ip對應的服務器實際上並沒有這個證書，導致了https請求失敗。

解決方法：

HttpClient中有一個    類，里面的方法中包含了需要驗證的所有ssl證書類型，而我們只需要重寫這個方法，並把需要驗證的證書設置為空，即命令客戶端不驗證任何ssl證書，就ok了。

關於http請求頭中的host字段：

https://blog.csdn.net/yzpbright/article/details/51052008

代碼：

 private JSONObject HttpPing(String dns, String uri, String qlb, String scheme) {
        String url = scheme + "://" + dns + uri;
        CloseableHttpClient httpclient = null;
        if (scheme.equals("http")) {
            httpclient = getHttpClient(qlb);
        } else if (scheme.equals("https")) {
            httpclient = getHttpsClient(qlb);
        } else{
            return null;
        }
        HttpGet httpGet = new HttpGet(url);
        CloseableHttpResponse httpResp = null;
        try {
            httpResp = httpclient.execute(httpGet);
        } catch (IOException e) {
            e.printStackTrace();
        }
        try {
            int statusCode = httpResp.getStatusLine().getStatusCode();
            if (statusCode == org.apache.http.HttpStatus.SC_OK) {
                return JSONObject.parseObject(EntityUtils.toString(httpResp.getEntity(), "UTF-8"));
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                httpResp.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return null;
    }
　　private CloseableHttpClient getHttpClient(String qlb) {
        HttpHost proxy = new HttpHost(qlb, 80, "http");
        //把代理設置到請求配置
        RequestConfig defaultRequestConfig = RequestConfig.custom()
                .setProxy(proxy)
                .build();
        CloseableHttpClient httpclient = HttpClients.custom().setDefaultRequestConfig(defaultRequestConfig).build();
        return httpclient;
    }

    private CloseableHttpClient getHttpsClient(String qlb) {
　　　　//這里設置客戶端不檢測服務器ssl證書
        try {
            X509TrustManager x509mgr = new X509TrustManager() {
                public void checkClientTrusted(X509Certificate[] xcs, String string) {
                }
                public void checkServerTrusted(X509Certificate[] xcs, String string) {
                }
                public X509Certificate[] getAcceptedIssuers() {
                    return null;
                }
            };
            SSLContext sslContext = SSLContext.getInstance("TLS");
            sslContext.init(null, new TrustManager[] { x509mgr }, null);
            SSLConnectionSocketFactory sslsf = new SSLConnectionSocketFactory(sslContext, SSLConnectionSocketFactory.ALLOW_ALL_HOSTNAME_VERIFIER);
            HttpHost proxy = new HttpHost(qlb, 443, "https");
            RequestConfig defaultRequestConfig = RequestConfig.custom()
                    .setProxy(proxy)
                    .build();
            CloseableHttpClient httpclient = HttpClients.custom().setSSLSocketFactory(sslsf).setDefaultRequestConfig(defaultRequestConfig).build();
            return httpclient;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }