java——HttpClient 代理模式发送Http Https

在setProxy()方法中设置代理IP后可以将url中的域名换成这个代理IP。

http很简单，但是https这样会报错。

问题：如何使用代理发送https请求？

客户端发送https请求之前会先向这台服务器请求ssl证书，并在客服端对这个证书做一个校验。

而使用代理IP时，实际上请求打到了这个代理IP上，而客户端并不知道这件事，他仍然在等待url域名中所对应的ssl证书，而这代理ip对应的服务器实际上并没有这个证书，导致了https请求失败。

解决方法：

HttpClient中有一个    类，里面的方法中包含了需要验证的所有ssl证书类型，而我们只需要重写这个方法，并把需要验证的证书设置为空，即命令客户端不验证任何ssl证书，就ok了。

关于http请求头中的host字段：

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

代码：

 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");
        //把代理设置到请求配置
        RequestConfig defaultRequestConfig = RequestConfig.custom()
                .setProxy(proxy)
                .build();
        CloseableHttpClient httpclient = HttpClients.custom().setDefaultRequestConfig(defaultRequestConfig).build();
        return httpclient;
    }

    private CloseableHttpClient getHttpsClient(String qlb) {
　　　　//这里设置客户端不检测服务器ssl证书
        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;
    }