java http请求设置代理 Proxy

HttpURLConnection、HttpClient设置代理Proxy

有如下一种需求,原本A要给C发送请求,但是因为网络原因,需要借助B才能实现,所以由原本的A->C变成了A->B->C。

这种情况,更多的见于内网请求由统一的网关做代理然后转发出去,比如你本地的机器想要对外上网,都是通过运营商给的出口IP也就是公网地址实现的。这种做法就是代理了。

研究了一下针对 HttpURLConnection和HttpClient这两种常见的http请求的代理:

一、HttpURLConnection设置请求代理

贴出一个utils类

具体代码如下:

public class ProxyUtils {

    public static final String CONTENT_TYPE = "application/x-www-form-urlencoded";

    public static String getResultByHttpConnectionProxy(String url, String content, String proxyHost, int proxyPort) {

        String result = "";
        OutputStream outputStream = null;
        InputStream inputStream = null;
        try {
            //设置proxy
            Proxy proxy = new Proxy(Proxy.Type.HTTP, new InetSocketAddress(proxyHost, proxyPort));
            URL proxyUrl = new URL(url);
            //判断是哪种类型的请求
            if (url.startsWith("https")) {
                HttpsURLConnection httpsURLConnection = (HttpsURLConnection) proxyUrl.openConnection(proxy);
                httpsURLConnection.setRequestProperty("Content-Type", CONTENT_TYPE);
                //允许写入
                httpsURLConnection.setDoInput(true);
                //允许写出
                httpsURLConnection.setDoOutput(true);
                //请求方法的类型 POST/GET
                httpsURLConnection.setRequestMethod("POST");
                //是否使用缓存
                httpsURLConnection.setUseCaches(false);
                //读取超时
                httpsURLConnection.setReadTimeout(15000);
                //连接超时
                httpsURLConnection.setConnectTimeout(15000);
                //设置SSL
                httpsURLConnection.setSSLSocketFactory(getSsf());
                //设置主机验证程序
                httpsURLConnection.setHostnameVerifier((s, sslSession) -> true);

                outputStream = httpsURLConnection.getOutputStream();
                outputStream.write(content.getBytes(StandardCharsets.UTF_8));
                outputStream.flush();
                inputStream = httpsURLConnection.getInputStream();
            } else {
                HttpURLConnection httpURLConnection = (HttpURLConnection) proxyUrl.openConnection(proxy);
                httpURLConnection.setRequestProperty("Content-Type", CONTENT_TYPE);
                httpURLConnection.setDoOutput(true);
                httpURLConnection.setDoInput(true);
                httpURLConnection.setRequestMethod("POST");
                httpURLConnection.setUseCaches(false);
                httpURLConnection.setConnectTimeout(15000);
                httpURLConnection.setReadTimeout(15000);

                outputStream = httpURLConnection.getOutputStream();
                outputStream.write(content.getBytes("UTF-8"));
                outputStream.flush();
                inputStream = httpURLConnection.getInputStream();
            }

            byte[] bytes = read(inputStream, 1024);
            result = (new String(bytes, "UTF-8")).trim();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (outputStream != null) {
                    outputStream.close();
                }
                if (inputStream != null) {
                    inputStream.close();
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return result;
    }

    public static byte[] read(InputStream inputStream, int bufferSize) throws IOException {
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        byte[] buffer = new byte[bufferSize];

        for (int num = inputStream.read(buffer); num != -1; num = inputStream.read(buffer)) {
            baos.write(buffer, 0, num);
        }

        baos.flush();
        return baos.toByteArray();
    }

    private static SSLSocketFactory getSsf() {
        SSLContext ctx = null;
        try {
            ctx = SSLContext.getInstance("TLS");
            ctx.init(new KeyManager[0],
                    new TrustManager[]{new ProxyUtils.DefaultTrustManager()},
                    new SecureRandom());
        } catch (Exception e) {
            e.printStackTrace();
        }
        assert ctx != null;
        return ctx.getSocketFactory();
    }

    private static final class DefaultTrustManager implements X509TrustManager {
        @Override
        public void checkClientTrusted(X509Certificate[] chain, String authType)
                throws CertificateException {
        }

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

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

上面的代码就是对httpsURLConnection设置了Proxy代理,也就是请求先会发到proxyHost:proxyPort,然后由其代理发到url。

二、HttpClient设置请求代理

贴出一个utils类

具体代码如下:

public class HttpclientUtils {

    private static final String CONTENT_TYPE = "application/x-www-form-urlencoded";

    public static String getResultByProxy(String url, String request, String proxyHost, int proxyPort) throws Exception {
        String response = null;
        HttpPost httpPost = null;
        try {
            HttpClient httpClient = getHttpClient(url);
            //设置请求配置类  重点就是在这里添加setProxy 设置代理
            RequestConfig requestConfig = RequestConfig.custom().setSocketTimeout(15000).setConnectTimeout(15000)
                    .setConnectionRequestTimeout(15000).setProxy(new HttpHost(proxyHost, proxyPort)).build();
            httpPost = new HttpPost(url);
            
            httpPost.setConfig(requestConfig);
            httpPost.addHeader("Content-Type", CONTENT_TYPE);
            httpPost.setEntity(new StringEntity(request, "utf-8"));

            response = getHttpClientResponse(httpPost, httpClient);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (null != httpPost) {
                httpPost.releaseConnection();
            }
        }
        return response;
    }

    private static String getHttpClientResponse(HttpPost httpPost, HttpClient httpClient) throws Exception {
        String result = null;
        HttpResponse httpResponse = httpClient.execute(httpPost);
        HttpEntity entity = httpResponse.getEntity();

        if (null != entity) {
            try (InputStream inputStream = entity.getContent()) {
                byte[] bytes = read(inputStream, 1024);
                result = new String(bytes, StandardCharsets.UTF_8);
            }
        }

        return result;
    }

    private static HttpClient getHttpClient(String url) throws Exception {
        HttpClient httpClient;
        String lowerURL = url.toLowerCase();
        if (lowerURL.startsWith("https")) {
            httpClient = createSSLClientDefault();
        } else {
            httpClient = HttpClients.createDefault();
        }
        return httpClient;
    }

    private static CloseableHttpClient createSSLClientDefault() throws Exception {
        SSLContext sslContext = new SSLContextBuilder().loadTrustMaterial(null, (chain, authType) -> true).build();
        SSLConnectionSocketFactory sslsf = new SSLConnectionSocketFactory(sslContext, (s, sslSession) -> true);
        return HttpClients.custom().setSSLSocketFactory(sslsf).build();
    }

    public static byte[] read(InputStream inputStream, int bufferSize) throws IOException {
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        byte[] buffer = new byte[bufferSize];

        for (int num = inputStream.read(buffer); num != -1; num = inputStream.read(buffer)) {
            baos.write(buffer, 0, num);
        }

        baos.flush();
        return baos.toByteArray();
    }
}

以上就是针对http、https的代理汇总,其实想想,就是通过 Proxy 对象,添加对应的代理地址和端口,实现了一层转发,可以想到nginx、gateway这种思想。

欢迎大家讨论学习,本人能力有限,也是摸索探究的,有不对的地方欢迎指正。

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