Apache HttpClient4使用教程

基於HttpClient 4.5.2

1. 執行GET請求
   CloseableHttpClient httpClient = HttpClients.custom() .build(); CloseableHttpResponse response = httpClient.execute(new HttpGet("https://www.baidu.com")); System.out.println(EntityUtils.toString(response.getEntity()));
2. 執行POST請求
   1. 提交form表單參數
      CloseableHttpClient httpClient = HttpClients.custom() .build(); HttpPost httpPost = new HttpPost("https://www.explame.com"); List<NameValuePair> formParams = new ArrayList<NameValuePair>(); //表單參數 formParams.add(new BasicNameValuePair("name1", "value1")); formParams.add(new BasicNameValuePair("name2", "value2")); UrlEncodedFormEntity entity = new UrlEncodedFormEntity(formParams, "utf-8"); httpPost.setEntity(entity); CloseableHttpResponse response = httpClient.execute(httpPost); System.out.println(EntityUtils.toString(response.getEntity()));
   2. 提交payload參數
      CloseableHttpClient httpClient = HttpClients.custom() .build(); HttpPost httpPost = new HttpPost("https://www.explame.com"); StringEntity entity = new StringEntity("{\"id\": \"1\"}"); httpPost.setEntity(entity); CloseableHttpResponse response = httpClient.execute(httpPost); System.out.println(EntityUtils.toString(response.getEntity()));
   3. post上傳文件
      CloseableHttpClient httpClient = HttpClients.custom() .build(); HttpPost httpPost = new HttpPost("https://www.example.com"); MultipartEntityBuilder multipartEntityBuilder = MultipartEntityBuilder.create(); //要上傳的文件 multipartEntityBuilder.addBinaryBody("file", new File("temp.txt")); httpPost.setEntity(multipartEntityBuilder.build()); CloseableHttpResponse response = httpClient.execute(httpPost); System.out.println(EntityUtils.toString(response.getEntity()));
   4. post提交multipart/form-data類型參數
      CloseableHttpClient httpClient = HttpClients.custom() .build(); HttpPost httpPost = new HttpPost("https://www.example.com"); MultipartEntityBuilder multipartEntityBuilder = MultipartEntityBuilder.create(); multipartEntityBuilder.addTextBody("username","wycm"); multipartEntityBuilder.addTextBody("passowrd","123"); //文件 multipartEntityBuilder.addBinaryBody("file", new File("temp.txt")); httpPost.setEntity(multipartEntityBuilder.build()); CloseableHttpResponse response = httpClient.execute(httpPost); System.out.println(EntityUtils.toString(response.getEntity()));
3. 設置User-Agent
   CloseableHttpClient httpClient = HttpClients.custom() .setUserAgent("Mozilla/5.0") .build(); CloseableHttpResponse response = httpClient.execute(new HttpGet("https://www.baidu.com")); System.out.println(EntityUtils.toString(response.getEntity()));

4. 設置重試處理器
   當請求超時, 會自動重試，最多3次
   HttpRequestRetryHandler retryHandler = (exception, executionCount, context) -> { if (executionCount >= 3) { return false; } if (exception instanceof InterruptedIOException) { return true; } if (exception instanceof UnknownHostException) { return true; } if (exception instanceof ConnectTimeoutException) { return true; } if (exception instanceof SSLException) { return true; } HttpClientContext clientContext = HttpClientContext.adapt(context); HttpRequest request = clientContext.getRequest(); boolean idempotent = !(request instanceof HttpEntityEnclosingRequest); if (idempotent) { return true; } return false; }; CloseableHttpClient httpClient = HttpClients.custom() .setRetryHandler(retryHandler) .build(); httpClient.execute(new HttpGet("https://www.baidu.com"));

5. 重定向策略
   1. HttpClient默認狀況
      會對30二、307的GET和HEAD請求以及全部的303狀態碼作重定向處理
   2. 關閉自動重定向
      CloseableHttpClient httpClient = HttpClients.custom() //關閉httpclient重定向 .disableRedirectHandling() .build();
   3. POST支持302狀態碼重定向
      CloseableHttpClient httpClient = HttpClients.custom() //post 302支持重定向 .setRedirectStrategy(new LaxRedirectStrategy()) .build(); CloseableHttpResponse response = httpClient.execute(new HttpPost("https://www.explame.com")); System.out.println(EntityUtils.toString(response.getEntity()));
6. 定製cookie
   • 方式一：經過addHeader方式設置（不推薦這種方式）
     CloseableHttpClient httpClient = HttpClients.custom() .build(); HttpGet httpGet = new HttpGet("http://www.example.com"); httpGet.addHeader("Cookie", "name=value"); httpClient.execute(httpGet);
     因爲HttpClient默認會維護cookie狀態。若是這個請求response中有Set-Cookie頭，那下次請求的時候httpclient默認會把這個Cookie帶上。而且會新建一行header。若是再遇到
     httpGet.addHeader("Cookie", "name=value");
     那麼下次請求則會有兩行name爲Cookie的header。
   • 方式二：經過CookieStore的方式，以瀏覽器中的cookie爲例（推薦）
     //此處直接粘貼瀏覽器cookie final String RAW_COOKIES = "name1=value1; name2=value2"; final CookieStore cookieStore = new BasicCookieStore(); for (String rawCookie : RAW_COOKIES.split("; ")){ String[] s = rawCookie.split("="); BasicClientCookie cookie = new BasicClientCookie(s[0], s[1]); cookie.setDomain("baidu.com"); cookie.setPath("/"); cookie.setSecure(false); cookie.setAttribute("domain", "baidu.com"); Calendar calendar = Calendar.getInstance(); calendar.add(Calendar.DAY_OF_MONTH, +5); cookie.setExpiryDate(calendar.getTime()); cookieStore.addCookie(cookie); } CloseableHttpClient httpClient = HttpClients.custom() .setDefaultCookieStore(cookieStore) .build(); httpClient.execute(new HttpGet("https://www.baidu.com"));
     這種方式把定製的cookie交給httpclient維護。
7. cookie管理
   • 方式一：初始化HttpClient時，傳入一個本身CookieStore對象
     CookieStore cookieStore = new BasicCookieStore(); CloseableHttpClient httpClient = HttpClients.custom() .setDefaultCookieStore(cookieStore) .build(); httpClient.execute(new HttpGet("https://www.baidu.com")); //請求一次後,清理cookie再發起一次新的請求 cookieStore.clear(); httpClient.execute(new HttpGet("https://www.baidu.com"));
   • 方式二：每次執行請求的時候傳入本身的HttpContext對象
     //注:HttpClientContext不是線程安全的，不要多個線程維護一個HttpClientContext HttpClientContext httpContext = HttpClientContext.create(); CloseableHttpClient httpClient = HttpClients.custom() .build(); httpClient.execute(new HttpGet("https://www.baidu.com"), httpContext); //請求一次後,清理cookie再發起一次新的請求 httpContext.getCookieStore().clear(); httpClient.execute(new HttpGet("https://www.baidu.com"));
8. http代理的配置
   CloseableHttpClient httpClient = HttpClients.custom() //設置代理 .setRoutePlanner(new DefaultProxyRoutePlanner(new HttpHost("localhost", 8888))) .build(); CloseableHttpResponse response = httpClient.execute(new HttpGet("http://www.example.com")); System.out.println(EntityUtils.toString(response.getEntity()));
9. SSL配置
   //默認信任 SSLContext sslContext = SSLContexts.custom() .loadTrustMaterial(KeyStore.getInstance(KeyStore.getDefaultType()) , (chain, authType) -> true).build(); Registry<ConnectionSocketFactory> socketFactoryRegistry = RegistryBuilder.<ConnectionSocketFactory>create() .register("http", new SocketProxyPlainConnectionSocketFactory()) .register("https", new SocketProxySSLConnectionSocketFactory(sslContext)) .build(); CloseableHttpClient httpClient = HttpClients.custom() .setConnectionManager(new PoolingHttpClientConnectionManager(socketFactoryRegistry)) .build(); HttpClientContext httpClientContext = HttpClientContext.create(); httpClientContext.setAttribute("socks.address", new InetSocketAddress("127.0.0.1", 1086)); CloseableHttpResponse response = httpClient.execute(new HttpGet("https://httpbin.org/ip"), httpClientContext); System.out.println(EntityUtils.toString(response.getEntity()));

10. socket代理配置

    static class SocketProxyPlainConnectionSocketFactory extends PlainConnectionSocketFactory{
        @Override
        public Socket createSocket(final HttpContext context) {
            InetSocketAddress socksAddr = (InetSocketAddress) context.getAttribute("socks.address");
            if (socksAddr != null){
                Proxy proxy = new Proxy(Proxy.Type.SOCKS, socksAddr);
                return new Socket(proxy);
            } else {
                return new Socket();
            }
        }
    }
    static class SocketProxySSLConnectionSocketFactory extends SSLConnectionSocketFactory {
        public SocketProxySSLConnectionSocketFactory(final SSLContext sslContext) {
            super(sslContext, NoopHostnameVerifier.INSTANCE);
        }
    
        @Override
        public Socket createSocket(final HttpContext context) {
            InetSocketAddress socksAddr = (InetSocketAddress) context.getAttribute("socks.address");
            if (socksAddr != null){
                Proxy proxy = new Proxy(Proxy.Type.SOCKS, socksAddr);
                return new Socket(proxy);
            } else {
                return new Socket();
            }
        }
    
    }
    /**
     * socket代理配置
     */
    public static void socketProxy() throws Exception {
        //默認信任
        SSLContext sslContext = SSLContexts.custom()
                .loadTrustMaterial(KeyStore.getInstance(KeyStore.getDefaultType())
                        , (X509Certificate[] chain, String authType) -> true).build();
        Registry<ConnectionSocketFactory> socketFactoryRegistry =
                RegistryBuilder.<ConnectionSocketFactory>create()
                        .register("http", new SocketProxyPlainConnectionSocketFactory())
                        .register("https", new SocketProxySSLConnectionSocketFactory(sslContext))
                        .build();
        CloseableHttpClient httpClient = HttpClients.custom()
                .setConnectionManager(new PoolingHttpClientConnectionManager(socketFactoryRegistry))
                .build();
        HttpClientContext httpClientContext = HttpClientContext.create();
        httpClientContext.setAttribute("socks.address", new InetSocketAddress("127.0.0.1", 1086));
        CloseableHttpResponse response = httpClient.execute(new HttpGet("https://httpbin.org/ip"), httpClientContext);
        System.out.println(EntityUtils.toString(response.getEntity()));
    }

11. 下載文件

    CloseableHttpClient httpClient = HttpClients.custom().build();
    CloseableHttpResponse response = httpClient.execute(new HttpGet("https://www.example.com"));
    InputStream is = response.getEntity().getContent();
    Files.copy(is, new File("temp.png").toPath(), StandardCopyOption.REPLACE_EXISTING);

    最後

• 完整Demo源碼下載地址:https://github.com/wycm/HttpClientDemo

版權聲明
做者：wycm
出處：https://www.cnblogs.com/w-y-c-m/p/9237335.html
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