✅ 常用 Java HTTP 客户端汇总及使用示例
在 Java 开发中,HTTP 客户端是与服务端交互的关键组件。随着技术发展,出现了多种 HTTP 客户端库,本文汇总了常用的 Java HTTP 客户端,介绍其特点、适用场景,并附上简单使用示例,方便开发者快速选择和上手。
1.常用 HTTP 客户端一览
名称 | 简介 | 特点 |
---|---|---|
HttpClient(JDK 自带) | Java 11 引入的官方 HTTP 客户端 | 支持异步、HTTP/2,API 现代 |
RestTemplate | Spring 提供的同步 HTTP 客户端(即将被淘汰) | 简洁,适合小项目;被 WebClient 替代 |
WebClient | Spring 5 提供的响应式 HTTP 客户端 | 支持响应式编程,推荐替代 RestTemplate |
OkHttpClient | Square 出品,轻量级高性能 HTTP 客户端 | 支持异步、连接池、拦截器 |
Apache HttpClient | Apache 出品的经典 HTTP 客户端库 | 功能强大、稳定、支持各种高级特性 |
Feign | 声明式 HTTP 客户端,适用于 Spring Cloud | 开发效率高,集成 Ribbon/Hystrix |
Retrofit | Square 出品,封装 OkHttp 的声明式客户端 | 强大的 JSON 自动转换,适合 REST API |
AsyncHttpClient | 异步非阻塞 HTTP 客户端(如 Netty 实现) | 高并发性能好,用于微服务场景 |
Vert.x WebClient | Vert.x 框架的异步 HTTP 客户端 | 轻量级、响应式,非常适合微服务 |
Jetty HttpClient | Jetty 提供的 HTTP 客户端实现 | 支持异步和 HTTP/2,常用于嵌入式 |
2.推荐选择场景
需求 | 推荐客户端 |
---|---|
简单同步请求 | RestTemplate(传统)或 HttpClient(Java 11+) |
响应式或高并发 | WebClient, AsyncHttpClient, Vert.x WebClient |
简洁封装、声明式调用 | Feign, Retrofit |
高度可定制 | OkHttp, Apache HttpClient |
3.各客户端 GET 和 POST 示例
1. HttpClient(Java 11+)
// GET 请求
HttpClient client = HttpClient.newHttpClient();HttpRequest getRequest = HttpRequest.newBuilder().uri(URI.create("https://jsonplaceholder.typicode.com/posts/1")).GET().build();HttpResponse<String> getResponse = client.send(getRequest, HttpResponse.BodyHandlers.ofString());
System.out.println("GET response: " + getResponse.body());// POST 请求
String json = "{\"title\":\"foo\",\"body\":\"bar\",\"userId\":1}";HttpRequest postRequest = HttpRequest.newBuilder().uri(URI.create("https://jsonplaceholder.typicode.com/posts")).header("Content-Type", "application/json").POST(HttpRequest.BodyPublishers.ofString(json)).build();HttpResponse<String> postResponse = client.send(postRequest, HttpResponse.BodyHandlers.ofString());
System.out.println("POST response: " + postResponse.body());
2. RestTemplate
RestTemplate restTemplate = new RestTemplate();// GET 请求
String getResult = restTemplate.getForObject("https://jsonplaceholder.typicode.com/posts/1", String.class);
System.out.println("GET response: " + getResult);// POST 请求
String url = "https://jsonplaceholder.typicode.com/posts";
Map<String, Object> postBody = new HashMap<>();
postBody.put("title", "foo");
postBody.put("body", "bar");
postBody.put("userId", 1);String postResult = restTemplate.postForObject(url, postBody, String.class);
System.out.println("POST response: " + postResult);
3. WebClient
WebClient client = WebClient.create();// GET 请求
client.get().uri("https://jsonplaceholder.typicode.com/posts/1").retrieve().bodyToMono(String.class).subscribe(response -> System.out.println("GET response: " + response));// POST 请求
String json = "{\"title\":\"foo\",\"body\":\"bar\",\"userId\":1}";client.post().uri("https://jsonplaceholder.typicode.com/posts").header("Content-Type", "application/json").bodyValue(json).retrieve().bodyToMono(String.class).subscribe(response -> System.out.println("POST response: " + response));
4. OkHttpClient
OkHttpClient client = new OkHttpClient();// GET 请求
Request getRequest = new Request.Builder().url("https://jsonplaceholder.typicode.com/posts/1").build();Response getResponse = client.newCall(getRequest).execute();
System.out.println("GET response: " + getResponse.body().string());// POST 请求
MediaType JSON = MediaType.get("application/json; charset=utf-8");
String json = "{\"title\":\"foo\",\"body\":\"bar\",\"userId\":1}";RequestBody body = RequestBody.create(json, JSON);
Request postRequest = new Request.Builder().url("https://jsonplaceholder.typicode.com/posts").post(body).build();Response postResponse = client.newCall(postRequest).execute();
System.out.println("POST response: " + postResponse.body().string());
5. Apache HttpClient
CloseableHttpClient client = HttpClients.createDefault();// GET 请求
HttpGet getRequest = new HttpGet("https://jsonplaceholder.typicode.com/posts/1");
CloseableHttpResponse getResponse = client.execute(getRequest);
System.out.println("GET response: " + EntityUtils.toString(getResponse.getEntity()));// POST 请求
HttpPost postRequest = new HttpPost("https://jsonplaceholder.typicode.com/posts");
postRequest.setHeader("Content-Type", "application/json");
StringEntity entity = new StringEntity("{\"title\":\"foo\",\"body\":\"bar\",\"userId\":1}");
postRequest.setEntity(entity);CloseableHttpResponse postResponse = client.execute(postRequest);
System.out.println("POST response: " + EntityUtils.toString(postResponse.getEntity()));
6. Feign
interface JsonPlaceholderClient {@RequestLine("GET /posts/1")String getPost();@RequestLine("POST /posts")@Headers("Content-Type: application/json")String createPost(String json);
}JsonPlaceholderClient client = Feign.builder().target(JsonPlaceholderClient.class, "https://jsonplaceholder.typicode.com");// GET 请求
String getResponse = client.getPost();
System.out.println("GET response: " + getResponse);// POST 请求
String json = "{\"title\":\"foo\",\"body\":\"bar\",\"userId\":1}";
String postResponse = client.createPost(json);
System.out.println("POST response: " + postResponse);
7. Retrofit
public interface ApiService {@GET("posts/1")Call<Post> getPost();@POST("posts")Call<Post> createPost(@Body Post post);
}Retrofit retrofit = new Retrofit.Builder().baseUrl("https://jsonplaceholder.typicode.com/").addConverterFactory(GsonConverterFactory.create()).build();ApiService service = retrofit.create(ApiService.class);// GET 请求
service.getPost().enqueue(new Callback<Post>() {public void onResponse(Call<Post> call, Response<Post> response) {System.out.println("GET response: " + response.body());}public void onFailure(Call<Post> call, Throwable t) {t.printStackTrace();}
});// POST 请求
Post newPost = new Post("foo", "bar", 1);
service.createPost(newPost).enqueue(new Callback<Post>() {public void onResponse(Call<Post> call, Response<Post> response) {System.out.println("POST response: " + response.body());}public void onFailure(Call<Post> call, Throwable t) {t.printStackTrace();}
});
8. AsyncHttpClient
AsyncHttpClient client = Dsl.asyncHttpClient();// GET 请求
client.prepareGet("https://jsonplaceholder.typicode.com/posts/1").execute().toCompletableFuture().thenAccept(response -> System.out.println("GET response: " + response.getResponseBody())).join();// POST 请求
String json = "{\"title\":\"foo\",\"body\":\"bar\",\"userId\":1}";client.preparePost("https://jsonplaceholder.typicode.com/posts").setHeader("Content-Type", "application/json").setBody(json).execute().toCompletableFuture().thenAccept(response -> System.out.println("POST response: " + response.getResponseBody())).join();
9. Vert.x WebClient
Vert.x 是一个轻量级、响应式的应用框架,其 WebClient 是异步非阻塞的 HTTP 客户端,非常适合高并发和微服务场景。
Vertx vertx = Vertx.vertx();
WebClient client = WebClient.create(vertx);// GET 请求
client.getAbs("https://jsonplaceholder.typicode.com/posts/1").send(ar -> {if (ar.succeeded()) {System.out.println("GET response: " + ar.result().bodyAsString());} else {ar.cause().printStackTrace();}});// POST 请求
JsonObject json = new JsonObject().put("title", "foo").put("body", "bar").put("userId", 1);client.postAbs("https://jsonplaceholder.typicode.com/posts").putHeader("Content-Type", "application/json").sendJsonObject(json, ar -> {if (ar.succeeded()) {System.out.println("POST response: " + ar.result().bodyAsString());} else {ar.cause().printStackTrace();}});
10. Jetty HttpClient
Jetty 提供的 HTTP 客户端,支持异步和 HTTP/2,适合嵌入式和高性能场景。
HttpClient client = new HttpClient();
client.start();// GET 请求
ContentResponse getResponse = client.GET("https://jsonplaceholder.typicode.com/posts/1");
System.out.println("GET response: " + getResponse.getContentAsString());// POST 请求
Request postRequest = client.POST("https://jsonplaceholder.typicode.com/posts");
postRequest.header("Content-Type", "application/json");
postRequest.content(new StringContentProvider("{\"title\":\"foo\",\"body\":\"bar\",\"userId\":1}"));ContentResponse postResponse = postRequest.send();
System.out.println("POST response: " + postResponse.getContentAsString());client.stop();
4.结语
随着 Java 生态的发展,HTTP 客户端的选择也愈发丰富和多样。无论是 JDK 自带的现代 HttpClient,还是功能强大的第三方库如 OkHttp、Apache HttpClient,以及适合响应式编程的 WebClient,都各有优势,满足不同场景需求。
选择合适的 HTTP 客户端,能极大提升开发效率和应用性能。希望本文的汇总与示例,能帮助你快速掌握各类客户端的基本用法,并根据项目需求做出最佳选择。
如果你有更多使用心得或想了解更深入的高级功能,欢迎留言交流,我们一起成长!