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Apache Commons HttpClient

简介

Apache HttpClient 组件是为扩展而设计的，同时提供对基本HTTP协议的强大支持。

http://java.net包提供了通过HTTP访问资源的基本功能，但它并没有提供许多应用程序所需的全部灵活性或功能。HttpClient 组件通过提供一个高效、最新、功能丰富的包来填补这一空白，该包实现了最新HTTP标准的客户端。

HttpClient 过去是 Commons 的一部分，现在是 Apache HttpComponents 的一部分。Apache HttpComponents 是 Apache 的顶级项目，负责创建和维护专注于 HTTP 和相关协议的 Java 组件工具集。因此文章后面将不再使用 Commons HttpClient 字样，而是使用 HttpClient 。

HttpClient 目前有三个大版本，他们是不兼容的，可以同时存在。HttpClient 3过去是 Commons 的一部分，所以一般来说看到 Apache HttpClient 3的说法指的就是 Commons HttpClient，所属包 org.apache.commons.httpclient，maven 依赖如下

<!-- HttpClient 3 -->
<dependency><groupId>commons-httpclient</groupId><artifactId>commons-httpclient</artifactId><version>3.1</version>
</dependency>

HttpClient 4 指的是 Apache HttpComponents 下的项目，所属包 org.apache.http，maven 依赖如下

<!-- HttpClient 4 -->
<dependency><groupId>org.apache.httpcomponents</groupId><artifactId>httpclient</artifactId><version>4.5.13</version>
</dependency>

HttpClient 5 指的是 Apache HttpComponents 下的最新项目，包结构是 org.apache.hc，依赖如下

<dependency><groupId>org.apache.httpcomponents.client5</groupId><artifactId>httpclient5</artifactId><version>5.1</version>
</dependency>

HttpClient 3 早已不在维护，推荐使用最新的HttpClient 5。HttpClient 5 支持（经典API）（异步API）（反应式API）。

下面我将简单介绍下这几个版本 HttpClient 的用法。

1. 原生API
   我们先来看看如果不使用 HttpClient 而是使用 Java 原生 API，写一个 http 请求的例子

package com.jjy.httpclient5demo.test;import javax.net.ssl.HttpsURLConnection;
import javax.net.ssl.SSLContext;
import javax.net.ssl.TrustManager;
import javax.net.ssl.X509TrustManager;
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.URL;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;public class JavaApi {public static void main(String[] args) {HttpsURLConnection conn = null;try {URL url = new URL("https://httpbin.org/get");conn = (HttpsURLConnection) url.openConnection();// https请求需要设置证书，为了简单此处默认信任服务器不做证书校验SSLContext sc = SSLContext.getInstance("SSL");sc.init(null, new TrustManager[]{new X509TrustManager() {@Overridepublic void checkClientTrusted(X509Certificate[] x509Certificates, String s) throws CertificateException {}@Overridepublic void checkServerTrusted(X509Certificate[] x509Certificates, String s) throws CertificateException {}@Overridepublic X509Certificate[] getAcceptedIssuers() {return new X509Certificate[0];}}}, new java.security.SecureRandom());conn.setSSLSocketFactory(sc.getSocketFactory());conn.setHostnameVerifier((s, sslSession) -> true);conn.setRequestMethod("GET");conn.setConnectTimeout(5000);conn.setReadTimeout(5000);conn.setUseCaches(false);conn.connect();InputStream is = conn.getInputStream();try (BufferedReader br = new BufferedReader(new InputStreamReader(is))) {StringBuilder sb = new StringBuilder();String line;while ((line = br.readLine()) != null) {sb.append(line).append("\n");}sb.deleteCharAt(sb.length() - 1);System.out.println(sb.toString());}} catch (Exception e) {e.printStackTrace();} finally {if (conn != null) {conn.disconnect();}}}
}

package com.jjy.httpclient5demo.test;import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.net.http.HttpHeaders;
import java.io.IOException;
import java.nio.charset.StandardCharsets;public class NativeJavaHttpClient {public static String get(String url) {HttpClient client = HttpClient.newHttpClient();HttpRequest request = HttpRequest.newBuilder().uri(URI.create(url)).header("Accept", "application/json") // 如果需要的话，设置请求头.GET().build();try {HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());int statusCode = response.statusCode();System.out.println("Status Code: " + statusCode);System.out.println("Response Headers: " + response.headers());return response.body();} catch (IOException | InterruptedException e) {e.printStackTrace();return null;}}public static void main(String[] args) {String url = "http://httpbin.org/get";String responseContent = NativeJavaHttpClient.get(url);System.out.println(responseContent);}
}

我们看到这个例子是一个相对比较简单的 https 的 get请求，没有参数。代码已经比较复杂了，如果是 post 请求，需要传递参数，需要保存cookie（有些请求需求登录，我们还要先模拟登录请求后手动将 cookie 保存下来，下次请求在把 cookie 设置上）等场景代码将更为复杂。并且原生 API 默认不支持异步不支持响应式等，这时候就轮到 HttpClient 大显手身了。

2. HttpClient 3

package com.jjy.httpclient5demo.test;import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.HttpMethod;
import org.apache.commons.httpclient.HttpStatus;
import org.apache.commons.httpclient.NameValuePair;
import org.apache.commons.httpclient.methods.GetMethod;import java.io.IOException;public class HttpClient3 {public static void main(String[] args) {// httpClient对象是线程安全的，可以单例使用，提升性能HttpClient httpClient = new HttpClient();
// 设置连接超时 和 socket超时httpClient.getHttpConnectionManager().getParams().setConnectionTimeout(2000);httpClient.getHttpConnectionManager().getParams().setSoTimeout(5000); // 响应超时HttpMethod getM = new GetMethod("http://httpbin.org/get");
// 设置请求头getM.setRequestHeader("Content-Type", "application/json");NameValuePair p1 = new NameValuePair("name", "zs");NameValuePair p2 = new NameValuePair("age", "11");
// 设置查询参数，相当于 ?name=zs&age=11getM.setQueryString(new NameValuePair[]{p1, p2});try {int code = httpClient.executeMethod(getM);if (code == HttpStatus.SC_OK) {// 获取结果字符串String res = getM.getResponseBodyAsString();// InputStream res = getM.getResponseBodyAsStream(); // 也可以转换为流System.out.println(res);} else {System.err.println("请求失败，状态码：" + code);}} catch (IOException e) {e.printStackTrace();} finally {// 释放连接资源getM.releaseConnection();}}
}

3. HttpClient 4

import org.apache.http.HttpEntity;
import org.apache.http.HttpStatus;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.util.EntityUtils;
import org.apache.http.client.utils.URIBuilder;import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;public class HttpClient4 {public static void main(String[] args) throws URISyntaxException {CloseableHttpClient httpClient = HttpClientBuilder.create().build();// 创建一个URIBuilder来构建带参数的URL  URIBuilder uriBuilder = new URIBuilder("http://httpbin.org/get");try {// 添加参数  uriBuilder.addParameter("name", "zs");uriBuilder.addParameter("age", "11");// 构建最终的URI  URI uri = uriBuilder.build();HttpGet httpGet = new HttpGet(uri);// 设置请求配置（超时等）  RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(2000) // 连接超时  .setConnectionRequestTimeout(2000) // 请求超时  .setSocketTimeout(2000) // 响应超时  .build();httpGet.setConfig(requestConfig);// 设置请求头（如果需要）  // httpGet.setHeader("Content-Type", "application/json"); // 注意：GET请求通常不需要Content-Type头  try (CloseableHttpResponse response = httpClient.execute(httpGet)) {int statusCode = response.getStatusLine().getStatusCode();if (statusCode == HttpStatus.SC_OK) {HttpEntity entity = response.getEntity();System.out.println(EntityUtils.toString(entity, "UTF-8"));} else {System.err.println("请求失败，状态码：" + statusCode);}} catch (IOException e) {System.err.println("请求异常：" + e.getMessage());}} catch (URISyntaxException e) {System.err.println("URI构建异常：" + e.getMessage());}}
}

Apache HttpClient 5

简介

Apache HttpClient 5 是一个开源的 HTTP 工具包，可以支持最新 HTTP 协议标准，且有丰富的 API 和强大的扩展特性，可以用于构建任何需要进行 HTTP 协议处理的应用程序。
下面将会介绍 Apache HttpClient 5 中最为常见的一些用法：
HttpClient 5 的 Get 请求、Post 请求、如何携带参数、JSON 参数、设置超时、异步请求、操作 Cookie、表单登录、基本认证、Digest 认证以及自定义 HTTP 请求拦截器等

依赖

maven

<!-- https://mvnrepository.com/artifact/org.apache.httpcomponents.client5/httpclient5 -->
<dependency><groupId>org.apache.httpcomponents.client5</groupId><artifactId>httpclient5</artifactId><version>5.1.3</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.apache.httpcomponents.client5/httpclient5-fluent -->
<dependency><groupId>org.apache.httpcomponents.client5</groupId><artifactId>httpclient5-fluent</artifactId><version>5.1.3</version>
</dependency>

HttpClient 5 GET 请求

package com.jjy.httpclient5demo.test;import org.apache.hc.client5.http.classic.methods.HttpGet; // 导入Apache HttpClient 5的HttpGet类，用于发送HTTP GET请求  
import org.apache.hc.client5.http.impl.classic.CloseableHttpClient; // 导入CloseableHttpClient类，表示一个可关闭的HTTP客户端  
import org.apache.hc.client5.http.impl.classic.CloseableHttpResponse; // 导入CloseableHttpResponse类，表示一个可关闭的HTTP响应  
import org.apache.hc.client5.http.impl.classic.HttpClients; // 导入HttpClients类，用于创建HttpClient实例  
import org.apache.hc.core5.http.HttpEntity; // 导入HttpEntity类，表示HTTP消息体  
import org.apache.hc.core5.http.ParseException; // 导入ParseException类，表示HTTP消息解析异常  
import org.apache.hc.core5.http.io.entity.EntityUtils; // 导入EntityUtils类，提供HTTP实体的工具方法  // 注意：下面的导入似乎是不相关的，因为该类并不是一个Servlet  
// import javax.servlet.http.HttpServlet;  
// import javax.servlet.http.HttpServletRequest;  import java.io.IOException; // 导入IO异常类  public class GetHttp5Client {/*** 发送GET请求并返回响应内容  ** @param url 请求的URL  * @return 响应内容的字符串形式*/public static String get(String url) {String resultContent = null; // 初始化响应内容的字符串为null  HttpGet httpGet = new HttpGet(url); // 创建HttpGet对象并设置请求的URL  try (CloseableHttpClient httpclient = HttpClients.createDefault()) { // 创建默认的CloseableHttpClient实例  try (CloseableHttpResponse response = httpclient.execute(httpGet)) { // 执行GET请求并获取响应  // 获取响应的状态信息  System.out.println(response.getVersion()); // 打印HTTP协议版本（例如：HTTP/1.1）  System.out.println(response.getCode()); // 打印响应的状态码（例如：200）  System.out.println(response.getReasonPhrase()); // 打印响应的状态描述（例如：OK）  HttpEntity entity = response.getEntity(); // 获取响应实体  // 将响应实体转换为字符串  resultContent = EntityUtils.toString(entity);}} catch (IOException | ParseException e) { // 捕获IO异常或HTTP消息解析异常  e.printStackTrace(); // 打印异常堆栈信息  }return resultContent; // 返回响应内容的字符串  }/*** 主函数，程序的入口点  ** @param args 命令行参数  */public static void main(String[] args) {// 测试GET请求，注意这里的URL已经被注释掉了，实际使用时可以取消注释并替换成需要的URL  // String url = "http://localhost:8080/user/loginwithcode";  // String url = "https://api.fastgpt.in/api/v1/chat/completions";  String url = "http://httpbin.org/get"; // 使用的测试URL  String s = GetHttp5Client.get(url); // 调用get方法发送GET请求并获取响应内容  System.out.println(s); // 打印响应内容  }
}

响应信息：

HTTP/1.1
200
OK
{"args": {}, "headers": {"Accept-Encoding": "gzip, x-gzip, deflate", "Host": "httpbin.org", "User-Agent": "Apache-HttpClient/5.1.3 (Java/17)", "X-Amzn-Trace-Id": "Root=1-62bb1891-5ab5e5376ed960471bf32f17"}, "origin": "47.251.4.198", "url": "http://httpbin.org/get"
}

HttpClient 5 Fluent GET

使用 Apache HttpClient 5 提供的 Fluent API 可以更便捷的发起 GET 请求，但是可操作的地方较少。

依赖：

<!-- https://mvnrepository.com/artifact/org.apache.httpcomponents.client5/httpclient5-fluent -->
<dependency><groupId>org.apache.httpcomponents.client5</groupId><artifactId>httpclient5-fluent</artifactId><version>5.1.3</version>
</dependency>

示例:

package com.jjy.httpclient5demo;import java.io.IOException;import org.apache.hc.client5.http.fluent.Request; // 导入Apache HttpClient 5的fluent API的Request类，用于构建HTTP请求  
import org.apache.hc.client5.http.fluent.Response; // 导入Apache HttpClient 5的fluent API的Response类，用于处理HTTP响应  /*** 使用Apache HttpClient 5的fluent API发送GET请求并获取响应内容  ** @author zbxmx*/
public class HttpClient5GetFluent {/*** 主函数，程序的入口点  ** @param args 命令行参数  */public static void main(String[] args) {// 调用get方法发送GET请求，并打印返回的响应内容  System.out.println(get("http://httpbin.org/get"));}/*** 发送GET请求并返回响应内容  ** @param url 请求的URL  * @return 响应内容的字符串形式*/public static String get(String url) {String result = null; // 初始化响应内容的字符串为null  try {// 使用fluent API构建GET请求并执行，获取响应对象  Response response = Request.get(url).execute();// 从响应对象中获取响应内容，并转换为字符串  result = response.returnContent().asString();} catch (IOException e) {// 捕获IO异常，并打印异常堆栈信息  e.printStackTrace();}// 返回响应内容的字符串  return result;}}

HttpClient5 GET 请求参数

使用 URIBuilder 的 addParameters() 方法来构建 GET 请求的参数。

package com.jjy.httpclient5demo.test;import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.ArrayList;
import java.util.List;import org.apache.hc.client5.http.classic.methods.HttpGet;
import org.apache.hc.client5.http.impl.classic.CloseableHttpClient;
import org.apache.hc.client5.http.impl.classic.CloseableHttpResponse;
import org.apache.hc.client5.http.impl.classic.HttpClients;
import org.apache.hc.core5.http.HttpEntity;
import org.apache.hc.core5.http.NameValuePair;
import org.apache.hc.core5.http.ParseException;
import org.apache.hc.core5.http.io.entity.EntityUtils;
import org.apache.hc.core5.http.message.BasicNameValuePair;
import org.apache.hc.core5.net.URIBuilder;/*** 使用Apache HttpClient 5的经典API发送带有参数的GET请求并获取响应内容** @author zbxmx*/
public class HttpClient5GetParams {/*** 主函数，程序的入口点** @param args 命令行参数*/public static void main(String[] args) {// 调用get方法发送带有参数的GET请求，并打印返回的响应内容String result = get("http://httpbin.org/get");System.out.println(result);}/*** 发送带有参数的GET请求并返回响应内容** @param url 请求的URL* @return 响应内容的字符串形式*/public static String get(String url) {String resultContent = null;// 创建HttpGet对象，设置请求的URLHttpGet httpGet = new HttpGet(url);// 创建存放表单参数的列表List<NameValuePair> nvps = new ArrayList<>();// 添加GET请求参数nvps.add(new BasicNameValuePair("username", "wdbyte.com"));nvps.add(new BasicNameValuePair("password", "secret"));// 使用URIBuilder构建新的URI，将参数添加到请求URL中try {URI uri = new URIBuilder(new URI(url)).addParameters(nvps) // 将参数添加到URL中.build(); // 构建完整的URI// 设置HttpGet对象的URIhttpGet.setUri(uri);} catch (URISyntaxException e) {// 如果URI构建出错，则抛出运行时异常throw new RuntimeException(e);}try (CloseableHttpClient httpclient = HttpClients.createDefault()) {// 创建默认的HttpClient实例try (CloseableHttpResponse response = httpclient.execute(httpGet)) {// 使用HttpClient执行GET请求，获取响应对象// 打印响应的HTTP版本、状态码和原因短语System.out.println(response.getVersion()); // HTTP/1.1System.out.println(response.getCode()); // 200System.out.println(response.getReasonPhrase()); // OKHttpEntity entity = response.getEntity();// 将响应实体转换为字符串resultContent = EntityUtils.toString(entity);}} catch (IOException | ParseException e) {// 捕获IO异常或解析异常，并打印异常堆栈信息e.printStackTrace();}// 返回响应内容的字符串return resultContent;}
}

输出信息：

{"args": {"password": "secret", "username": "wdbyte.com"}, "headers": {"Accept-Encoding": "gzip, x-gzip, deflate", "Host": "httpbin.org", "User-Agent": "Apache-HttpClient/5.1.3 (Java/1.8.0_151)", "X-Amzn-Trace-Id": "Root=1-62ecc660-69d58a226aefb1b6226541ec"}, "origin": "218.26.154.94", "url": "http://httpbin.org/get?username=wdbyte.com&password=secret"
}

HttpClient 5 POST 请求

下面演示发起一个 POST 请求，并携带表单参数。

package com.jjy.httpclient5demo.test;import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.List;import org.apache.hc.client5.http.classic.methods.HttpPost;
import org.apache.hc.client5.http.entity.UrlEncodedFormEntity;
import org.apache.hc.client5.http.impl.classic.CloseableHttpClient;
import org.apache.hc.client5.http.impl.classic.CloseableHttpResponse;
import org.apache.hc.client5.http.impl.classic.HttpClients;
import org.apache.hc.core5.http.HttpEntity;
import org.apache.hc.core5.http.NameValuePair;
import org.apache.hc.core5.http.ParseException;
import org.apache.hc.core5.http.io.entity.EntityUtils;
import org.apache.hc.core5.http.message.BasicNameValuePair;
/*** 使用Apache HttpClient 5的经典API发送带有表单参数的POST请求并获取响应内容** @author zbxmx*/
public class HttpClient5Post {/*** 主函数，程序的入口点** @param args 命令行参数*/public static void main(String[] args) {// 调用post方法发送带有表单参数的POST请求，并打印返回的响应内容String result = post("http://httpbin.org/post");System.out.println(result);}/*** 发送带有表单参数的POST请求并返回响应内容** @param url 请求的URL* @return 响应内容的字符串形式*/public static String post(String url) {String result = null;// 创建HttpPost对象，设置请求的URLHttpPost httpPost = new HttpPost(url);// 创建存放表单参数的列表List<NameValuePair> nvps = new ArrayList<>();// 添加POST请求参数nvps.add(new BasicNameValuePair("username", "wdbyte.com"));nvps.add(new BasicNameValuePair("password", "secret"));// 创建UrlEncodedFormEntity，将表单参数添加到POST请求中httpPost.setEntity(new UrlEncodedFormEntity(nvps));try (CloseableHttpClient httpclient = HttpClients.createDefault()) {// 创建默认的HttpClient实例try (CloseableHttpResponse response = httpclient.execute(httpPost)) {// 使用HttpClient执行POST请求，获取响应对象// 打印响应的HTTP版本、状态码和原因短语System.out.println(response.getVersion()); // HTTP/1.1System.out.println(response.getCode()); // 200System.out.println(response.getReasonPhrase()); // OK// 获取响应实体HttpEntity entity = response.getEntity();// 将响应实体转换为字符串result = EntityUtils.toString(entity);// 确保响应实体被完全消费，避免资源泄露EntityUtils.consume(entity);}} catch (IOException | ParseException e) {// 捕获IO异常，并打印异常堆栈信息e.printStackTrace();}// 返回响应内容的字符串return result;}
}

输出结果：

{"args": {}, "data": "", "files": {}, "form": {"password": "secret", "username": "wdbyte.com"}, "headers": {"Accept-Encoding": "gzip, x-gzip, deflate", "Content-Length": "35", "Content-Type": "application/x-www-form-urlencoded; charset=ISO-8859-1", "Host": "httpbin.org", "User-Agent": "Apache-HttpClient/5.1.3 (Java/17.0.9)", "X-Amzn-Trace-Id": "Root=1-660fe4f3-76d02ec05aa7a6535e833aad"}, "json": null, "origin": "218.26.154.94", "url": "http://httpbin.org/post"
}

HttpClient 5 Fluent POST

使用 Apache HttpClient 5 提供的 Fluent API 可以更便捷的发起 POST 请求，但是可操作的地方较少。

package com.jjy.httpclient5demo.test;import java.io.IOException;import org.apache.hc.client5.http.fluent.Request;
import org.apache.hc.core5.http.message.BasicNameValuePair;/*** @author zbzmx*/
public class HttpClient5PostFluent {public static void main(String[] args) {String result = post("http://httpbin.org/post");System.out.println(result);}public static String post(String url) {String result = null;Request request = Request.post(url);// POST 请求参数request.bodyForm(new BasicNameValuePair("username", "wdbyte.com"),new BasicNameValuePair("password", "secret"));try {result = request.execute().returnContent().asString();} catch (IOException e) {e.printStackTrace();}return result;}
}

HttpClient5 POST JSON 参数

package com.jjy.httpclient5demo.test;import java.io.IOException;import org.apache.hc.client5.http.classic.methods.HttpPost;
import org.apache.hc.client5.http.impl.classic.CloseableHttpClient;
import org.apache.hc.client5.http.impl.classic.CloseableHttpResponse;
import org.apache.hc.client5.http.impl.classic.HttpClients;
import org.apache.hc.core5.http.ContentType;
import org.apache.hc.core5.http.ParseException;
import org.apache.hc.core5.http.io.entity.EntityUtils;
import org.apache.hc.core5.http.io.entity.StringEntity;/*** @author zbxmx*/
public class HttpClient5PostWithJson {public static void main(String[] args) {String json = "{"+ "    \"password\": \"secret\","+ "    \"username\": \"wdbyte.com\""+ "}";String result = post("http://httpbin.org/post", json);System.out.println(result);}public static String post(String url, String jsonBody) {String result = null;HttpPost httpPost = new HttpPost(url);httpPost.setEntity(new StringEntity(jsonBody, ContentType.APPLICATION_JSON));try (CloseableHttpClient httpclient = HttpClients.createDefault()) {try (CloseableHttpResponse response = httpclient.execute(httpPost)) {// 获取响应信息result = EntityUtils.toString(response.getEntity());}} catch (IOException | ParseException e) {e.printStackTrace();}return result;}}

输出结果：

{"args": {}, "data": "{    \"password\": \"secret\",    \"username\": \"wdbyte.com\"}", "files": {}, "form": {}, "headers": {"Accept-Encoding": "gzip, x-gzip, deflate", "Content-Length": "55", "Content-Type": "application/json; charset=UTF-8", "Host": "httpbin.org", "User-Agent": "Apache-HttpClient/5.1.3 (Java/17.0.9)", "X-Amzn-Trace-Id": "Root=1-660ff565-0afd9ffd3d41ed4417652ca1"}, "json": {"password": "secret", "username": "wdbyte.com"}, "origin": "218.26.154.94", "url": "http://httpbin.org/post"
}

HttpClient 5 设置超时

使用 RequestConfig 对象来配置超时时间。

package com.jjy.httpclient5demo.test;import java.io.IOException;import org.apache.hc.client5.http.classic.methods.HttpGet;
import org.apache.hc.client5.http.config.RequestConfig;
import org.apache.hc.client5.http.impl.classic.CloseableHttpClient;
import org.apache.hc.client5.http.impl.classic.CloseableHttpResponse;
import org.apache.hc.client5.http.impl.classic.HttpClients;
import org.apache.hc.core5.http.HttpEntity;
import org.apache.hc.core5.http.ParseException;
import org.apache.hc.core5.http.io.entity.EntityUtils;
import org.apache.hc.core5.util.Timeout;/*** @author zbxmx*/
public class HttpClient5GetWithTimeout {public static void main(String[] args) {String result = get("http://httpbin.org/get");System.out.println(result);}public static String get(String url) {String resultContent = null;// 设置超时时间RequestConfig config = RequestConfig.custom().setConnectTimeout(Timeout.ofMilliseconds(5000L)).setConnectionRequestTimeout(Timeout.ofMilliseconds(5000L)).setResponseTimeout(Timeout.ofMilliseconds(5000L)).build();// 请求级别的超时HttpGet httpGet = new HttpGet(url);//httpGet.setConfig(config);//try (CloseableHttpClient httpclient = HttpClients.createDefault()) {// 客户端级别的超时try (CloseableHttpClient httpclient = HttpClients.custom().setDefaultRequestConfig(config).build()) {try (CloseableHttpResponse response = httpclient.execute(httpGet)) {// 获取状态码System.out.println(response.getVersion()); // HTTP/1.1System.out.println(response.getCode()); // 200System.out.println(response.getReasonPhrase()); // OKHttpEntity entity = response.getEntity();// 获取响应信息resultContent = EntityUtils.toString(entity);}} catch (IOException | ParseException e) {e.printStackTrace();}return resultContent;}}

HttpClient 5 异步请求

下面演示三种 HttpClient 5 异步请求方式。

package com.jjy.httpclient5demo.test;import java.io.IOException;
import java.nio.CharBuffer;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;import org.apache.hc.client5.http.async.methods.AbstractCharResponseConsumer;
import org.apache.hc.client5.http.async.methods.SimpleHttpRequest;
import org.apache.hc.client5.http.async.methods.SimpleHttpRequests;
import org.apache.hc.client5.http.async.methods.SimpleHttpResponse;
import org.apache.hc.client5.http.impl.async.CloseableHttpAsyncClient;
import org.apache.hc.client5.http.impl.async.HttpAsyncClients;
import org.apache.hc.core5.concurrent.FutureCallback;
import org.apache.hc.core5.http.ContentType;
import org.apache.hc.core5.http.HttpException;
import org.apache.hc.core5.http.HttpResponse;
import org.apache.hc.core5.http.nio.AsyncRequestProducer;
import org.apache.hc.core5.http.nio.support.AsyncRequestBuilder;/*** HttpClient 5 异步请求* @author https://www.wdbyte.com**/
public class HttpClient5Async {public static void main(String[] args) {getAsync1("http://httpbin.org/get");getAsync2("http://httpbin.org/get");getAsync3("http://httpbin.org/get");}/*** 异步请求** @param url* @return*/public static String getAsync1(String url) {try (CloseableHttpAsyncClient httpclient = HttpAsyncClients.createDefault()) {// 开始 http clinethttpclient.start();// 执行请求SimpleHttpRequest request1 = SimpleHttpRequests.get(url);Future<SimpleHttpResponse> future = httpclient.execute(request1, null);// 等待直到返回完毕SimpleHttpResponse response1 = future.get();System.out.println("getAsync1:" + request1.getRequestUri() + "->" + response1.getCode());} catch (IOException | ExecutionException | InterruptedException e) {throw new RuntimeException(e);}return null;}/*** 异步请求，根据响应情况回调** @param url* @return*/public static String getAsync2(String url) {try (CloseableHttpAsyncClient httpclient = HttpAsyncClients.createDefault()) {// 开始 http clinethttpclient.start();// 根据请求响应情况进行回调操作CountDownLatch latch = new CountDownLatch(1);SimpleHttpRequest request = SimpleHttpRequests.get(url);httpclient.execute(request, new FutureCallback<SimpleHttpResponse>() {@Overridepublic void completed(SimpleHttpResponse response2) {latch.countDown();System.out.println("getAsync2:" + request.getRequestUri() + "->" + response2.getCode());}@Overridepublic void failed(Exception ex) {latch.countDown();System.out.println("getAsync2:" + request.getRequestUri() + "->" + ex);}@Overridepublic void cancelled() {latch.countDown();System.out.println("getAsync2:" + request.getRequestUri() + " cancelled");}});latch.await();} catch (IOException | InterruptedException e) {throw new RuntimeException(e);}return null;}/*** 异步请求，对响应流做点什么** @param url* @return*/public static String getAsync3(String url) {try (CloseableHttpAsyncClient httpclient = HttpAsyncClients.createDefault()) {// 开始 http clinethttpclient.start();// 根据请求响应情况进行回调操作SimpleHttpRequest request = SimpleHttpRequests.get(url);CountDownLatch latch = new CountDownLatch(1);AsyncRequestProducer producer = AsyncRequestBuilder.get("http://httpbin.org/get").build();AbstractCharResponseConsumer<HttpResponse> consumer3 = new AbstractCharResponseConsumer<HttpResponse>() {HttpResponse response;@Overrideprotected void start(HttpResponse response, ContentType contentType) throws HttpException, IOException {System.out.println("getAsync3: 开始响应....");this.response = response;}@Overrideprotected int capacityIncrement() {return Integer.MAX_VALUE;}@Overrideprotected void data(CharBuffer data, boolean endOfStream) throws IOException {System.out.println("getAsync3: 收到数据....");// Do something useful}@Overrideprotected HttpResponse buildResult() throws IOException {System.out.println("getAsync3: 接收完毕...");return response;}@Overridepublic void releaseResources() {}};httpclient.execute(producer, consumer3, new FutureCallback<HttpResponse>() {@Overridepublic void completed(HttpResponse response) {latch.countDown();System.out.println("getAsync3: "+request.getRequestUri() + "->" + response.getCode());}@Overridepublic void failed(Exception ex) {latch.countDown();System.out.println("getAsync3: "+request.getRequestUri() + "->" + ex);}@Overridepublic void cancelled() {latch.countDown();System.out.println("getAsync3: "+request.getRequestUri() + " cancelled");}});latch.await();} catch (IOException | InterruptedException e) {throw new RuntimeException(e);}return null;}
}

输出结果

getAsync1:/get->200
getAsync2:/get->200
getAsync3: 开始响应....
getAsync3: 收到数据....
getAsync3: 收到数据....
getAsync3: 收到数据....
getAsync3: 接收完毕...
getAsync3: /get->200

HttpClient 5 获取 Cookie

请求 http://httpbin.org/cookies/set/cookieName/www.wdbyte.com 的响应中会带有一个Cookie 信息，其中 name 为 cookieName，value 为 www.wdbyte.com，我们以此用作测试。

package com.jjy.httpclient5demo.test;import java.util.List;import org.apache.hc.client5.http.classic.methods.HttpGet;
import org.apache.hc.client5.http.cookie.BasicCookieStore;
import org.apache.hc.client5.http.cookie.Cookie;
import org.apache.hc.client5.http.cookie.CookieStore;
import org.apache.hc.client5.http.impl.classic.CloseableHttpClient;
import org.apache.hc.client5.http.impl.classic.CloseableHttpResponse;
import org.apache.hc.client5.http.impl.classic.HttpClients;
import org.apache.hc.client5.http.impl.cookie.BasicClientCookie;
import org.apache.hc.client5.http.protocol.HttpClientContext;
import org.apache.hc.core5.http.io.entity.EntityUtils;/*** 这个例子演示了使用本地HTTP上下文填充, 自定义属性*/
public class HttpClient5WithCookie {public static void main(final String[] args) throws Exception {try (final CloseableHttpClient httpclient = HttpClients.createDefault()) {// 创建一个本地的 Cookie 存储final CookieStore cookieStore = new BasicCookieStore();// BasicClientCookie clientCookie = new BasicClientCookie("name", "www.wdbyte.com");// clientCookie.setDomain("http://httpbin.org/cookies");// 过期时间// clientCookie.setExpiryDate(new Date());// 添加到本地 Cookie// cookieStore.addCookie(clientCookie);// 创建本地 HTTP 请求上下文 HttpClientContextfinal HttpClientContext localContext = HttpClientContext.create();// 绑定 cookieStore 到 localContextlocalContext.setCookieStore(cookieStore);final HttpGet httpget = new HttpGet("http://httpbin.org/cookies/set/cookieName/www.wdbyte.com");System.out.println("执行请求 " + httpget.getMethod() + " " + httpget.getUri());// 获取 Coolie 信息try (final CloseableHttpResponse response = httpclient.execute(httpget, localContext)) {System.out.println("----------------------------------------");System.out.println(response.getCode() + " " + response.getReasonPhrase());final List<Cookie> cookies = cookieStore.getCookies();for (int i = 0; i < cookies.size(); i++) {System.out.println("Local cookie: " + cookies.get(i));}EntityUtils.consume(response.getEntity());}}}}

输出结果：

执行请求 GET http://httpbin.org/cookies/set/cookieName/www.wdbyte.com
----------------------------------------
200 OK
Local cookie: [name: cookieName; value: www.wdbyte.com; domain: httpbin.org; path: /; expiry: null]

HttpClient 5 读取文件内容请求

准备一个 JSON 内容格式的文件 params.json。

{"name":"www.wdbyte.com"}

读取这个文件作为请求参数发起请求。

package com.jjy.httpclient5demo.test;import java.io.File;
import java.io.FileInputStream;import org.apache.hc.client5.http.classic.methods.HttpPost;
import org.apache.hc.client5.http.impl.classic.CloseableHttpClient;
import org.apache.hc.client5.http.impl.classic.CloseableHttpResponse;
import org.apache.hc.client5.http.impl.classic.HttpClients;
import org.apache.hc.core5.http.ContentType;
import org.apache.hc.core5.http.io.entity.EntityUtils;
import org.apache.hc.core5.http.io.entity.FileEntity;
import org.apache.hc.core5.http.io.entity.InputStreamEntity;/*** 加载数据流作为 POST 请求参数*/
public class HttpClient5ChunkEncodedPost {public static void main(final String[] args) throws Exception {String params = "/Users/darcy/params.json";try (final CloseableHttpClient httpclient = HttpClients.createDefault()) {final HttpPost httppost = new HttpPost("http://httpbin.org/post");final InputStreamEntity reqEntity = new InputStreamEntity(new FileInputStream(params), -1,ContentType.APPLICATION_JSON);// 也可以使用 FileEntity 的形式// FileEntity reqEntity = new FileEntity(new File(params), ContentType.APPLICATION_JSON);httppost.setEntity(reqEntity);System.out.println("执行请求 " + httppost.getMethod() + " " + httppost.getUri());try (final CloseableHttpResponse response = httpclient.execute(httppost)) {System.out.println("----------------------------------------");System.out.println(response.getCode() + " " + response.getReasonPhrase());System.out.println(EntityUtils.toString(response.getEntity()));}}}
}

输出结果

执行请求 POST http://httpbin.org/post
----------------------------------------
200 OK
{"args": {}, "data": "{\"name\":\"www.wdbyte.com\"}\n", "files": {}, "form": {}, "headers": {"Accept-Encoding": "gzip, x-gzip, deflate", "Content-Length": "26", "Content-Type": "application/json; charset=UTF-8", "Host": "httpbin.org", "User-Agent": "Apache-HttpClient/5.1.3 (Java/1.8.0_151)", "X-Amzn-Trace-Id": "Root=1-62ee4d95-1f956d4303cea09c52694c86"}, "json": {"name": "www.wdbyte.com"}, "origin": "42.120.74.238", "url": "http://httpbin.org/post"
}

HttpClient 5 表单登录

表单登录可以理解为发起一个携带了认证信息的请求，然后得到响应的 Cookie 的过程。当然这里不仅仅适用于表单登录，也可以是简单的发起一个携带了表单信息的请求。

本应该使用 POST 请求发送表单参数测试，但是在 httpbin.org 中没有对应的接口用于测试，所以这里换成了 GET 请求

package com.jjy.httpclient5demo.test;import java.util.ArrayList;
import java.util.List;import org.apache.hc.client5.http.classic.methods.HttpGet;
import org.apache.hc.client5.http.cookie.BasicCookieStore;
import org.apache.hc.client5.http.cookie.Cookie;
import org.apache.hc.client5.http.entity.UrlEncodedFormEntity;
import org.apache.hc.client5.http.impl.classic.CloseableHttpClient;
import org.apache.hc.client5.http.impl.classic.CloseableHttpResponse;
import org.apache.hc.client5.http.impl.classic.HttpClients;
import org.apache.hc.core5.http.HttpEntity;
import org.apache.hc.core5.http.NameValuePair;
import org.apache.hc.core5.http.io.entity.EntityUtils;
import org.apache.hc.core5.http.message.BasicNameValuePair;/*** 演示基于表单的登录** @author zbxmx*/
public class HttpClient5FormLogin {public static void main(final String[] args) throws Exception {final BasicCookieStore cookieStore = new BasicCookieStore();try (final CloseableHttpClient httpclient = HttpClients.custom().setDefaultCookieStore(cookieStore).build()) {// 本应该使用 POST 请求发送表单参数，但是在 httpbin.org 中没有对应的接口用于测试，所以这里换成了 GET 请求// HttpPost httpPost = new HttpPost("http://httpbin.org/cookies/set/username/wdbyte.com");HttpGet httpPost = new HttpGet("http://httpbin.org/cookies/set/username/wdbyte.com");// POST 表单请求参数List<NameValuePair> nvps = new ArrayList<>();nvps.add(new BasicNameValuePair("username", "wdbyte.com"));nvps.add(new BasicNameValuePair("password", "secret"));httpPost.setEntity(new UrlEncodedFormEntity(nvps));try (final CloseableHttpResponse response2 = httpclient.execute(httpPost)) {final HttpEntity entity = response2.getEntity();System.out.println("Login form get: " + response2.getCode() + " " + response2.getReasonPhrase());System.out.println("当前响应信息 "+EntityUtils.toString(entity));;System.out.println("Post 登录 Cookie:");final List<Cookie> cookies = cookieStore.getCookies();if (cookies.isEmpty()) {System.out.println("None");} else {for (int i = 0; i < cookies.size(); i++) {System.out.println("- " + cookies.get(i));}}}}}
}

输出结果：

Login form get: 200 OK
当前响应信息 {"cookies": {"username": "wdbyte.com"}
}Post 登录 Cookie:
- [name: username; value: wdbyte.com; domain: httpbin.org; path: /; expiry: null]

HttpClient 5 Basic Authorization

HTTP 基本认证（Basic Authorization）是一种比较简单的认证实现，主要流程如下

1. 请求一个需要进行基本认证的 HTTP 接口，但是没有携带认证信息。

2. 此时会响应 401 状态码，并在响应 header 中的 WWW-Authenticate 提示需要进行基本认证。

3. 用户把需要提交认证信息进行冒号拼接，然后进行 base64 编码，再在得到的字符串开头拼接上 Basic 放入请求头 Authorization 中。

4. 认证成功，响应成功。

你可以通过浏览器打开下面这个 URL 进行基本认证测试。

http://httpbin.org/basic-auth/admin/123456

package com.jjy.httpclient5demo.test;import org.apache.hc.client5.http.auth.AuthScope;
import org.apache.hc.client5.http.auth.UsernamePasswordCredentials;
import org.apache.hc.client5.http.classic.methods.HttpGet;
import org.apache.hc.client5.http.impl.auth.BasicCredentialsProvider;
import org.apache.hc.client5.http.impl.classic.CloseableHttpClient;
import org.apache.hc.client5.http.impl.classic.CloseableHttpResponse;
import org.apache.hc.client5.http.impl.classic.HttpClients;
import org.apache.hc.core5.http.io.entity.EntityUtils;/*** 一个简单的示例,它使用HttpClient执行HTTP请求;* 一个需要进行用户身份验证的目标站点。*/
public class HttpClient5BasicAuthentication {public static void main(final String[] args) throws Exception {final BasicCredentialsProvider credsProvider = new BasicCredentialsProvider();credsProvider.setCredentials(new AuthScope("httpbin.org", 80),new UsernamePasswordCredentials("admin", "123456".toCharArray()));try (final CloseableHttpClient httpclient = HttpClients.custom().setDefaultCredentialsProvider(credsProvider).build()) {final HttpGet httpget = new HttpGet("http://httpbin.org/basic-auth/admin/123456");System.out.println("执行请求" + httpget.getMethod() + " " + httpget.getUri());try (final CloseableHttpResponse response = httpclient.execute(httpget)) {System.out.println("----------------------------------------");System.out.println(response.getCode() + " " + response.getReasonPhrase());System.out.println(EntityUtils.toString(response.getEntity()));}}}
}

输出结果

执行请求GET http://httpbin.org/basic-auth/user/passwd
----------------------------------------
200 OK
{"authenticated": true, "user": "user"
}

HttpClient 5 Digest Authorization

HTTP Basic Authorization 的缺点显而易见，密码通过明文传输存在一定的安全风险，Digest Authorization 认证方式解决了明文传输的问题，这里不过多介绍 Digest 的相关内容，通过一个图简单的示意 Digest 认证方式的流程。

package com.jjy.httpclient5demo.test;import org.apache.hc.client5.http.auth.AuthExchange;
import org.apache.hc.client5.http.auth.AuthScheme;
import org.apache.hc.client5.http.auth.AuthScope;
import org.apache.hc.client5.http.auth.UsernamePasswordCredentials;
import org.apache.hc.client5.http.classic.methods.HttpGet;
import org.apache.hc.client5.http.impl.auth.BasicCredentialsProvider;
import org.apache.hc.client5.http.impl.auth.DigestScheme;
import org.apache.hc.client5.http.impl.classic.CloseableHttpClient;
import org.apache.hc.client5.http.impl.classic.CloseableHttpResponse;
import org.apache.hc.client5.http.impl.classic.HttpClients;
import org.apache.hc.client5.http.protocol.HttpClientContext;
import org.apache.hc.core5.http.HttpHost;
import org.apache.hc.core5.http.io.entity.EntityUtils;/**** HttpClient如何验证多个请求的示例* 使用相同的摘要方案。在初始请求/响应交换之后* 共享相同执行上下文的所有后续请求都可以重用* 要向服务器进行身份验证的最后一个摘要nonce值。*/
public class HttpClient5PreemptiveDigestAuthentication {public static void main(final String[] args) throws Exception {try (final CloseableHttpClient httpclient = HttpClients.createDefault()) {final HttpHost target = new HttpHost("http", "httpbin.org", 80);final HttpClientContext localContext = HttpClientContext.create();final BasicCredentialsProvider credentialsProvider = new BasicCredentialsProvider();credentialsProvider.setCredentials(new AuthScope(target),new UsernamePasswordCredentials("admin", "123456".toCharArray()));localContext.setCredentialsProvider(credentialsProvider);final HttpGet httpget = new HttpGet("http://httpbin.org/digest-auth/auth/admin/123456");System.out.println("执行请求 " + httpget.getMethod() + " " + httpget.getUri());for (int i = 0; i < 2; i++) {try (final CloseableHttpResponse response = httpclient.execute(target, httpget, localContext)) {System.out.println("----------------------------------------");System.out.println(response.getCode() + " " + response.getReasonPhrase());EntityUtils.consume(response.getEntity());final AuthExchange authExchange = localContext.getAuthExchange(target);if (authExchange != null) {final AuthScheme authScheme = authExchange.getAuthScheme();if (authScheme instanceof DigestScheme) {final DigestScheme digestScheme = (DigestScheme) authScheme;System.out.println("Nonce: " + digestScheme.getNonce() +"; count: " + digestScheme.getNounceCount());}}}}}}}

HttpClient 5 拦截器

HttpClient 5 中的拦截器可以对请求过程的各个阶段进行拦截处理，通过 HttpClientBuilder 中的关于 Interceptor 的方法可以看到可以

HttpClient5 拦截器

下面编写一个示例，发起三次请求，每次请求都在请求头 herader 中增加一个 request-id 参数，然后对 request-id 值为 2 的请求直接响应 404 结束。

package com.jjy.httpclient5demo.test;import java.io.IOException;
import java.util.concurrent.atomic.AtomicLong;import org.apache.hc.client5.http.classic.ExecChain;
import org.apache.hc.client5.http.classic.ExecChain.Scope;
import org.apache.hc.client5.http.classic.ExecChainHandler;
import org.apache.hc.client5.http.classic.methods.HttpGet;
import org.apache.hc.client5.http.impl.ChainElement;
import org.apache.hc.client5.http.impl.classic.CloseableHttpClient;
import org.apache.hc.client5.http.impl.classic.CloseableHttpResponse;
import org.apache.hc.client5.http.impl.classic.HttpClients;
import org.apache.hc.core5.http.ClassicHttpRequest;
import org.apache.hc.core5.http.ClassicHttpResponse;
import org.apache.hc.core5.http.ContentType;
import org.apache.hc.core5.http.EntityDetails;
import org.apache.hc.core5.http.Header;
import org.apache.hc.core5.http.HttpEntity;
import org.apache.hc.core5.http.HttpException;
import org.apache.hc.core5.http.HttpRequest;
import org.apache.hc.core5.http.HttpRequestInterceptor;
import org.apache.hc.core5.http.HttpStatus;
import org.apache.hc.core5.http.io.entity.EntityUtils;
import org.apache.hc.core5.http.io.entity.StringEntity;
import org.apache.hc.core5.http.message.BasicClassicHttpResponse;
import org.apache.hc.core5.http.protocol.HttpContext;/*** 展示如何在请求和响应时进行拦截进行自定义处理。*/
public class HttpClient5Interceptors {public static void main(final String[] args) throws Exception {try (final CloseableHttpClient httpclient = HttpClients.custom()// 添加一个请求 id 到请求 header.addRequestInterceptorFirst(new HttpRequestInterceptor() {private final AtomicLong count = new AtomicLong(0);@Overridepublic void process(final HttpRequest request,final EntityDetails entity,final HttpContext context) throws HttpException, IOException {request.setHeader("request-id", Long.toString(count.incrementAndGet()));}}).addExecInterceptorAfter(ChainElement.PROTOCOL.name(), "custom", new ExecChainHandler() {// 请求 id 为 2 的，模拟 404 响应，并自定义响应的内容。@Overridepublic ClassicHttpResponse execute(final ClassicHttpRequest request,final Scope scope,final ExecChain chain) throws IOException, HttpException {final Header idHeader = request.getFirstHeader("request-id");if (idHeader != null && "2".equalsIgnoreCase(idHeader.getValue())) {final ClassicHttpResponse response = new BasicClassicHttpResponse(HttpStatus.SC_NOT_FOUND,"Oppsie");response.setEntity(new StringEntity("bad luck", ContentType.TEXT_PLAIN));return response;} else {return chain.proceed(request, scope);}}}).build()) {for (int i = 0; i < 3; i++) {final HttpGet httpget = new HttpGet("http://httpbin.org/get");try (final CloseableHttpResponse response = httpclient.execute(httpget)) {System.out.println("----------------------------------------");System.out.println("执行请求 " + httpget.getMethod() + " " + httpget.getUri());System.out.println(response.getCode() + " " + response.getReasonPhrase());System.out.println(EntityUtils.toString(response.getEntity()));}}}}}

输出结果

----------------------------------------
执行请求 GET http://httpbin.org/get
200 OK
{"args": {}, "headers": {"Accept-Encoding": "gzip, x-gzip, deflate", "Host": "httpbin.org", "Request-Id": "1", "User-Agent": "Apache-HttpClient/5.1.3 (Java/1.8.0_151)", "X-Amzn-Trace-Id": "Root=1-62f615ba-658ccd42182d22534dbba82c"}, "origin": "42.120.75.221", "url": "http://httpbin.org/get"
}----------------------------------------
执行请求 GET http://httpbin.org/get
404 Oppsie
bad luck
----------------------------------------
执行请求 GET http://httpbin.org/get
200 OK
{"args": {}, "headers": {"Accept-Encoding": "gzip, x-gzip, deflate", "Host": "httpbin.org", "Request-Id": "3", "User-Agent": "Apache-HttpClient/5.1.3 (Java/1.8.0_151)", "X-Amzn-Trace-Id": "Root=1-62f615bb-4eb6ba10736ace0e21d0cb8c"}, "origin": "42.120.75.221", "url": "http://httpbin.org/get"
}

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