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本文 Github.com/niumoo/JavaNotes 和 未读代码博客 已经收录，有很多知识点和系列文章。
超文本传输协议（HTTP）可能是当今互联网上最重要的协议之一，Web 服务、微服务以及支持网络的各种设备上的服务几乎都是 HTTP 协议，HTTP 协议已经从 Web 浏览器走向了更广泛的使用场景。
虽然 java.net 包已经提供了 HTTP 访问资源的基本功能，但是它不够灵活，而且不能随心所欲的进行自定义。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。
这篇文章介绍 Apache HttpClient 5 中最为常见的一些用法，通过这篇文章可以快速的入门使用 HttpClient 5，主要内容包括 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。
HttpClient 5 依赖
HttpClient 5 Maven 依赖
<!-- 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 Gradle 依赖
implementation 'org.apache.httpcomponents.client5:httpclient5:5.1.3' implementation 'org.apache.httpcomponents.client5:httpclient5-fluent:5.1.3' HttpClient 5 GET 请求
package com.wdbyte.httpclient; import java.io.IOException; 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.ParseException; import org.apache.hc.core5.http.io.entity.EntityUtils; /** * @author https://www.wdbyte.com */ public class HttpClient5Get { 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; HttpGet httpGet = new HttpGet(url); try (CloseableHttpClient httpclient = HttpClients.createDefault()) { try (CloseableHttpResponse response = httpclient.execute(httpGet)) { // 获取状态码 System.out.println(response.getVersion()); // HTTP/1.1 System.out.println(response.getCode()); // 200 System.out.println(response.getReasonPhrase()); // OK HttpEntity entity = response.getEntity(); // 获取响应信息 resultContent = EntityUtils.toString(entity); } } catch (IOException | ParseException e) { e.printStackTrace(); } return resultContent; } } 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.wdbyte.httpclient; import java.io.IOException; import org.apache.hc.client5.http.fluent.Request; import org.apache.hc.client5.http.fluent.Response; /** * @author https://www.wdbyte.com */ public class HttpClient5GetFluent { public static void main(String[] args) { System.out.println(get("http://httpbin.org/get")); } public static String get(String url) { String result = null; try { Response response = Request.get(url).execute(); result = response.returnContent().asString(); } catch (IOException e) { e.printStackTrace(); } return result; } } 输出信息：
{ "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=1-62bb190e-1ba46a92645843a04c55da32" }, "origin": "47.251.4.198", "url": "http://httpbin.org/get" } HttpClient5 GET 请求参数
使用 URIBuilder 的 addParameters() 方法来构建 GET 请求的参数。
package com.wdbyte.httpclient; 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; /** * @author https://www.wdbyte.com */ public class HttpClient5GetParams { 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; HttpGet httpGet = new HttpGet(url); // 表单参数 List<NameValuePair> nvps = new ArrayList<>(); // GET 请求参数 nvps.add(new BasicNameValuePair("username", "wdbyte.com")); nvps.add(new BasicNameValuePair("password", "secret")); // 增加到请求 URL 中 try { URI uri = new URIBuilder(new URI(url)) .addParameters(nvps) .build(); httpGet.setUri(uri); } catch (URISyntaxException e) { throw new RuntimeException(e); } try (CloseableHttpClient httpclient = HttpClients.createDefault()) { try (CloseableHttpResponse response = httpclient.execute(httpGet)) { // 获取状态码 System.out.println(response.getVersion()); // HTTP/1.1 System.out.println(response.getCode()); // 200 System.out.println(response.getReasonPhrase()); // OK HttpEntity entity = response.getEntity(); // 获取响应信息 resultContent = EntityUtils.toString(entity); } } catch (IOException | ParseException e) { e.printStackTrace(); } 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": "42.120.75.185", "url": "http://httpbin.org/get?username=wdbyte.com&password=secret" } 下面是通过抓包得到的请求响应信息格式：
// 请求信息 GET /get?username=wdbyte.com&password=secret HTTP/1.1 Accept-Encoding: gzip, x-gzip, deflate Host: httpbin.org Connection: keep-alive User-Agent: Apache-HttpClient/5.1.3 (Java/1.8.0_151) // 响应信息 HTTP/1.1 200 OK Date: Fri, 05 Aug 2022 07:27:30 GMT Content-Type: application/json Content-Length: 405 Connection: keep-alive Server: gunicorn/19.9.0 Access-Control-Allow-Origin: * Access-Control-Allow-Credentials: true { "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": "42.120.75.185", "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。
参数：username=wdbyte.com&password=secret
package com.wdbyte.httpclient; import java.io.IOException; 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; /** * @author https://www.wdbyte.com */ public class HttpClient5Post { 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; HttpPost httpPost = new HttpPost(url); // 表单参数 List<NameValuePair> nvps = new ArrayList<>(); // POST 请求参数 nvps.add(new BasicNameValuePair("username", "wdbyte.com")); nvps.add(new BasicNameValuePair("password", "secret")); httpPost.setEntity(new UrlEncodedFormEntity(nvps)); try (CloseableHttpClient httpclient = HttpClients.createDefault()) { try (CloseableHttpResponse response = httpclient.execute(httpPost)) { System.out.println(response.getVersion()); // HTTP/1.1 System.out.println(response.getCode()); // 200 System.out.println(response.getReasonPhrase()); // OK HttpEntity entity = response.getEntity(); // 获取响应信息 result = EntityUtils.toString(entity); // 确保流被完全消费 EntityUtils.consume(entity); } } catch (IOException | ParseException e) { e.printStackTrace(); } return result; } } 输出信息：
HTTP/1.1 200 OK { "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)", "X-Amzn-Trace-Id": "Root=1-62bb1ac8-489b2100728c81d70797a482" }, "json": null, "origin": "183.128.136.89", "url": "http://httpbin.org/post" } 下面是通过 Wireshark 抓包得到的请求信息：
POST /post HTTP/1.1 Accept-Encoding: gzip, x-gzip, deflate Content-Length: 35 Content-Type: application/x-www-form-urlencoded; charset=ISO-8859-1 Host: httpbin.org Connection: keep-alive User-Agent: Apache-HttpClient/5.1.3 (Java/17) username=wdbyte.com&password=secret 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。
一样发送一个简单的表单参数：username=wdbyte.com&password=secret
package com.wdbyte.httpclient; import java.io.IOException; import org.apache.hc.client5.http.fluent.Request; import org.apache.hc.core5.http.message.BasicNameValuePair; /** * @author https://www.wdbyte.com */ 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; } } 输出信息：
{ "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)", "X-Amzn-Trace-Id": "Root=1-62bb1c8a-7aee8c004f06919f31a2b533" }, "json": null, "origin": "183.128.136.89", "url": "http://httpbin.org/post" } HttpClient5 POST JSON 参数
使用 StringEntity 类存入 JSON 参数。
package com.wdbyte.httpclient; 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.ParseException; import org.apache.hc.core5.http.io.entity.EntityUtils; import org.apache.hc.core5.http.io.entity.StringEntity; /** * @author https://www.wdbyte.com */ 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; } } 输出信息：
{ "args": {}, "data": "{ "password": "secret", "username": "wdbyte.com"}", "files": {}, "form": {}, "headers": { "Accept-Encoding": "gzip, x-gzip, deflate", "Content-Length": "55", "Content-Type": "text/plain; charset=ISO-8859-1", "Host": "httpbin.org", "User-Agent": "Apache-HttpClient/5.1.3 (Java/17)", "X-Amzn-Trace-Id": "Root=1-62bb1dbb-5a963c1d798b06be3ee1a15e" }, "json": { "password": "secret", "username": "wdbyte.com" }, "origin": "183.128.136.89", "url": "http://httpbin.org/post" } 下面是通过 Wireshark 抓包得到的请求响应信息：
// 请求信息 POST /post HTTP/1.1 Accept-Encoding: gzip, x-gzip, deflate Content-Length: 55 Content-Type: application/json; charset=UTF-8 Host: httpbin.org Connection: keep-alive User-Agent: Apache-HttpClient/5.1.3 (Java/17) { "password": "secret", "username": "wdbyte.com"} // 响应信息 HTTP/1.1 200 OK Date: Tue, 28 Jun 2022 15:30:17 GMT Content-Type: application/json Content-Length: 573 Connection: keep-alive Server: gunicorn/19.9.0 Access-Control-Allow-Origin: * Access-Control-Allow-Credentials: true { "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)", "X-Amzn-Trace-Id": "Root=1-62bb1e89-64db55730a0361c720232ccd" }, "json": { "password": "secret", "username": "wdbyte.com" }, "origin": "183.128.136.89", "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.wdbyte.httpclient; 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 https://www.wdbyte.com */ 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/1.1 System.out.println(response.getCode()); // 200 System.out.println(response.getReasonPhrase()); // OK HttpEntity 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.wdbyte.httpclient; 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 * @date 2022/06/25 */ 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 clinet httpclient.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 clinet httpclient.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>() { @Override public void completed(SimpleHttpResponse response2) { latch.countDown(); System.out.println("getAsync2:" + request.getRequestUri() + "->" + response2.getCode()); } @Override public void failed(Exception ex) { latch.countDown(); System.out.println("getAsync2:" + request.getRequestUri() + "->" + ex); } @Override public 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 clinet httpclient.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; @Override protected void start(HttpResponse response, ContentType contentType) throws HttpException, IOException { System.out.println("getAsync3: 开始响应...."); this.response = response; } @Override protected int capacityIncrement() { return Integer.MAX_VALUE; } @Override protected void data(CharBuffer data, boolean endOfStream) throws IOException { System.out.println("getAsync3: 收到数据...."); // Do something useful } @Override protected HttpResponse buildResult() throws IOException { System.out.println("getAsync3: 接收完毕..."); return response; } @Override public void releaseResources() { } }; httpclient.execute(producer, consumer3, new FutureCallback<HttpResponse>() { @Override public void completed(HttpResponse response) { latch.countDown(); System.out.println("getAsync3: "+request.getRequestUri() + "->" + response.getCode()); } @Override public void failed(Exception ex) { latch.countDown(); System.out.println("getAsync3: "+request.getRequestUri() + "->" + ex); } @Override public 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。
Postman 请求测试，可以看到响应了 Cookie 信息。
下面编写 Java 代码进行请求测试
package com.wdbyte.httpclient; 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 HttpClientContext final HttpClientContext localContext = HttpClientContext.create(); // 绑定 cookieStore 到 localContext localContext.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.wdbyte.httpclient; 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
示例代码：
package com.wdbyte.httpclient; 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 https://www.wdbyte.com */ 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
- 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。
- 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。
- 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。
- 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。
在 Apache HttpClient 5 中的实现方式。
package com.wdbyte.httpclient; 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" } 通过抓包可以看到完整的 HTTP 请求响应过程。
// 请求 GET /basic-auth/user/passwd HTTP/1.1 Accept-Encoding: gzip, x-gzip, deflate Host: httpbin.org Connection: keep-alive User-Agent: Apache-HttpClient/5.1.3 (Java/1.8.0_151) // 响应 HTTP/1.1 401 UNAUTHORIZED Date: Sat, 06 Aug 2022 08:25:33 GMT Content-Length: 0 Connection: keep-alive Server: gunicorn/19.9.0 WWW-Authenticate: Basic realm="Fake Realm" Access-Control-Allow-Origin: * Access-Control-Allow-Credentials: true // 请求 GET /basic-auth/user/passwd HTTP/1.1 Host: httpbin.org Connection: keep-alive User-Agent: Apache-HttpClient/5.1.3 (Java/1.8.0_151) Authorization: Basic dXNlcjpwYXNzd2Q= // 响应 HTTP/1.1 200 OK Date: Sat, 06 Aug 2022 08:25:33 GMT Content-Type: application/json Content-Length: 47 Connection: keep-alive Server: gunicorn/19.9.0 Access-Control-Allow-Origin: * Access-Control-Allow-Credentials: true { "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。
下面是代码演示。
package com.wdbyte.httpclient; 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()); } } } } } } } 通过抓包工具可以清晰的看到 2 次请求的流程，在最后一次请求中，直接共享了认证信息，没有再次的重新认证的流程。
// 1. 请求 GET /digest-auth/auth/admin/123456 HTTP/1.1 Accept-Encoding: gzip, x-gzip, deflate Host: httpbin.org Connection: keep-alive User-Agent: Apache-HttpClient/5.1.3 (Java/1.8.0_151) // 2. 详情，提示认证，给出参数 HTTP/1.1 401 UNAUTHORIZED Date: Fri, 12 Aug 2022 07:11:06 GMT Content-Type: text/html; charset=utf-8 Content-Length: 0 Connection: keep-alive Server: gunicorn/19.9.0 WWW-Authenticate: Digest realm="me@kennethreitz.com", nonce="8dc5e7974a86a6fcc3cf73230b0c4a93", qop="auth", opaque="64b7f68b386c3acc38131f7472aa2079", algorithm=MD5, stale=FALSE Set-Cookie: stale_after=never; Path=/ Set-Cookie: fake=fake_value; Path=/ Access-Control-Allow-Origin: * Access-Control-Allow-Credentials: true // 3. 参数+密码 加密后再次请求 GET /digest-auth/auth/admin/123456 HTTP/1.1 Host: httpbin.org Connection: keep-alive User-Agent: Apache-HttpClient/5.1.3 (Java/1.8.0_151) Cookie: fake=fake_value; stale_after=never Authorization: Digest username="admin", realm="me@kennethreitz.com", nonce="8dc5e7974a86a6fcc3cf73230b0c4a93", uri="/digest-auth/auth/admin/123456", response="7c6726f8ac54c1ba28e19c71b2fc7338", qop=auth, nc=00000001, cnonce="2fa61501d47a9d39", algorithm=MD5, opaque="64b7f68b386c3acc38131f7472aa2079" // 4. 认证成功，响应 HTTP/1.1 200 OK Date: Fri, 12 Aug 2022 07:11:08 GMT Content-Type: application/json Content-Length: 48 Connection: keep-alive Server: gunicorn/19.9.0 Set-Cookie: fake=fake_value; Path=/ Set-Cookie: stale_after=never; Path=/ Access-Control-Allow-Origin: * Access-Control-Allow-Credentials: true { "authenticated": true, "user": "admin" } // 5. 再次请求，共享了登录状态。 GET /digest-auth/auth/admin/123456 HTTP/1.1 Accept-Encoding: gzip, x-gzip, deflate Host: httpbin.org Connection: keep-alive User-Agent: Apache-HttpClient/5.1.3 (Java/1.8.0_151) Cookie: fake=fake_value; stale_after=never Authorization: Digest username="admin", realm="me@kennethreitz.com", nonce="8dc5e7974a86a6fcc3cf73230b0c4a93", uri="/digest-auth/auth/admin/123456", response="9955ac79f6a51a876a326449447f549d", qop=auth, nc=00000002, cnonce="2fa61501d47a9d39", algorithm=MD5, opaque="64b7f68b386c3acc38131f7472aa2079" // 5. 认证成功，响应 HTTP/1.1 200 OK Date: Fri, 12 Aug 2022 07:11:09 GMT Content-Type: application/json Content-Length: 48 Connection: keep-alive Server: gunicorn/19.9.0 Set-Cookie: fake=fake_value; Path=/ Set-Cookie: stale_after=never; Path=/ Access-Control-Allow-Origin: * Access-Control-Allow-Credentials: true { "authenticated": true, "user": "admin" } 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进行拦截的节点。
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.wdbyte.httpclient; 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); @Override public 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。 @Override public 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" } 一如既往，文章代码都存放在 Github.com/niumoo/javaNotes.
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