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java?http請求設(shè)置代理Proxy的兩種常見方法

更新時間：2023年11月25日 14:35:58 作者：幾層山下

代理是一種常見的設(shè)計模式,其目的就是為其他對象提供一個代理以控制對某個對象的訪問,這篇文章主要給大家介紹了關(guān)于java?http請求設(shè)置代理Proxy的兩種常見方法,需要的朋友可以參考下

HttpURLConnection、HttpClient設(shè)置代理Proxy

有如下一種需求，原本A要給C發(fā)送請求，但是因為網(wǎng)絡(luò)原因，需要借助B才能實現(xiàn)，所以由原本的A->C變成了A->B->C。

這種情況，更多的見于內(nèi)網(wǎng)請求由統(tǒng)一的網(wǎng)關(guān)做代理然后轉(zhuǎn)發(fā)出去，比如你本地的機器想要對外上網(wǎng)，都是通過運營商給的出口IP也就是公網(wǎng)地址實現(xiàn)的。這種做法就是代理了。

研究了一下針對 HttpURLConnection和HttpClient這兩種常見的http請求的代理：

一、HttpURLConnection設(shè)置請求代理

貼出一個utils類

具體代碼如下：

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 {
            //設(shè)置proxy
            Proxy proxy = new Proxy(Proxy.Type.HTTP, new InetSocketAddress(proxyHost, proxyPort));
            URL proxyUrl = new URL(url);
            //判斷是哪種類型的請求
            if (url.startsWith("https")) {
                HttpsURLConnection httpsURLConnection = (HttpsURLConnection) proxyUrl.openConnection(proxy);
                httpsURLConnection.setRequestProperty("Content-Type", CONTENT_TYPE);
                //允許寫入
                httpsURLConnection.setDoInput(true);
                //允許寫出
                httpsURLConnection.setDoOutput(true);
                //請求方法的類型 POST/GET
                httpsURLConnection.setRequestMethod("POST");
                //是否使用緩存
                httpsURLConnection.setUseCaches(false);
                //讀取超時
                httpsURLConnection.setReadTimeout(15000);
                //連接超時
                httpsURLConnection.setConnectTimeout(15000);
                //設(shè)置SSL
                httpsURLConnection.setSSLSocketFactory(getSsf());
                //設(shè)置主機驗證程序
                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;
        }
    }
}

上面的代碼就是對httpsURLConnection設(shè)置了Proxy代理，也就是請求先會發(fā)到proxyHost:proxyPort,然后由其代理發(fā)到url。

二、HttpClient設(shè)置請求代理

貼出一個utils類

具體代碼如下：

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);
            //設(shè)置請求配置類  重點就是在這里添加setProxy 設(shè)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();
    }
}

以上就是針對http、https的代理匯總，其實想想，就是通過 Proxy 對象，添加對應(yīng)的代理地址和端口，實現(xiàn)了一層轉(zhuǎn)發(fā)，可以想到nginx、gateway這種思想。