Apache HttpClient4使用教程[亲测有效]

Apache HttpClient4使用教程[亲测有效]基于HttpClient4.5.2执行GET请求CloseableHttpClienthttpClient=HttpClients.custom().build();CloseableHttpResponseresponse=httpClient.execute(newHttpGet("https://www.baidu.com"));…

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基于HttpClient 4.5.2

  1. 执行GET请求

    CloseableHttpClient httpClient = HttpClients.custom()
                    .build();
    CloseableHttpResponse response = httpClient.execute(new HttpGet("https://www.baidu.com"));
    System.out.println(EntityUtils.toString(response.getEntity()));
    
  2. 执行POST请求

    1. 提交form表单参数
      CloseableHttpClient httpClient = HttpClients.custom()
              .build();
      HttpPost httpPost = new HttpPost("https://www.explame.com");
      List<NameValuePair> formParams = new ArrayList<NameValuePair>();
      //表单参数
      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参数
      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上传文件
      CloseableHttpClient httpClient = HttpClients.custom()
              .build();
      HttpPost httpPost = new HttpPost("https://www.example.com");
      MultipartEntityBuilder multipartEntityBuilder = MultipartEntityBuilder.create();
      //要上传的文件
      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类型参数
      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. 设置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. 设置重试处理器
    当请求超时, 会自动重试,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默认情况
      会对302、307的GET和HEAD请求以及所有的303状态码做重定向处理
    2. 关闭自动重定向
      CloseableHttpClient httpClient = HttpClients.custom()
               //关闭httpclient重定向
              .disableRedirectHandling()
              .build();
      
    3. POST支持302状态码重定向
      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. 定制cookie

    • 方式一:通过addHeader方式设置(不推荐这种方式)
          CloseableHttpClient httpClient = HttpClients.custom()
                  .build();
          HttpGet httpGet = new HttpGet("http://www.example.com");
          httpGet.addHeader("Cookie", "name=value");
          httpClient.execute(httpGet);
      

      由于HttpClient默认会维护cookie状态。如果这个请求response中有Set-Cookie头,那下次请求的时候httpclient默认会把这个Cookie带上。并且会新建一行header。如果再遇到
      httpGet.addHeader("Cookie", "name=value");
      那么下次请求则会有两行name为Cookie的header。

    • 方式二:通过CookieStore的方式,以浏览器中的cookie为例(推荐)
      //此处直接粘贴浏览器cookiefinal 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"));

      这种方式把定制的cookie交给httpclient维护。

  7. cookie管理

    • 方式一:初始化HttpClient时,传入一个自己CookieStore对象
      CookieStore cookieStore = new BasicCookieStore();
      CloseableHttpClient httpClient = HttpClients.custom()
              .setDefaultCookieStore(cookieStore)
              .build();
      httpClient.execute(new HttpGet("https://www.baidu.com"));
      //请求一次后,清理cookie再发起一次新的请求
      cookieStore.clear();
      httpClient.execute(new HttpGet("https://www.baidu.com"));
      
    • 方式二:每次执行请求的时候传入自己的HttpContext对象
      //注:HttpClientContext不是线程安全的,不要多个线程维护一个HttpClientContext
      HttpClientContext httpContext = HttpClientContext.create();
      CloseableHttpClient httpClient = HttpClients.custom()
              .build();
      httpClient.execute(new HttpGet("https://www.baidu.com"), httpContext);
      //请求一次后,清理cookie再发起一次新的请求
      httpContext.getCookieStore().clear();
      httpClient.execute(new HttpGet("https://www.baidu.com"));
      
  8. http代理的配置

    CloseableHttpClient httpClient = HttpClients.custom()
            //设置代理
            .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

    //默认信任
    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 {
        //默认信任
        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. 下载文件

    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);
    
    

最后

版权声明
作者:wycm
出处:https://blog.csdn.net/vwycm/article/details/88638996
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