当前位置：首页 > news >正文

java.net.http 包详解

news 2025/11/13 8:43:11

java.net.http 包是 Java 11 引入的 HTTP 客户端 API，提供了现代、灵活且功能强大的 HTTP 客户端功能，替代了传统的 HttpURLConnection。

核心类

1. HttpClient

HTTP 客户端的主要入口点，用于发送请求和接收响应。

主要特性：

支持 HTTP/1.1 和 HTTP/2
同步和异步请求
WebSocket 支持
连接池管理
重定向处理
认证支持

创建 HttpClient 示例：

HttpClient client = HttpClient.newBuilder().version(HttpClient.Version.HTTP_2)  // 使用HTTP/2.followRedirects(HttpClient.Redirect.NORMAL)  // 跟随重定向.connectTimeout(Duration.ofSeconds(20))  // 连接超时.proxy(ProxySelector.of(new InetSocketAddress("proxy.example.com", 80)))  // 代理.authenticator(Authenticator.getDefault())  // 认证.build();

2. HttpRequest

表示要发送的 HTTP 请求。

构建请求示例：

HttpRequest request = HttpRequest.newBuilder().uri(URI.create("https://example.com/api")).header("Content-Type", "application/json").timeout(Duration.ofMinutes(2)).POST(HttpRequest.BodyPublishers.ofString("{\"key\":\"value\"}")).build();

BodyPublishers 类型：

ofString() - 从字符串创建请求体
ofByteArray() - 从字节数组创建请求体
ofFile() - 从文件创建请求体
noBody() - 无请求体

3. HttpResponse

表示接收到的 HTTP 响应。

处理响应体：

body() - 获取响应体
BodyHandlers 用于处理响应体：
- ofString() - 将响应体作为字符串
- ofByteArray() - 将响应体作为字节数组
- ofFile() - 将响应体写入文件
- discarding() - 丢弃响应体

同步请求示例

HttpClient client = HttpClient.newHttpClient();
HttpRequest request = HttpRequest.newBuilder().uri(URI.create("https://example.com")).build();HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());System.out.println("Status code: " + response.statusCode());
System.out.println("Response body: " + response.body());

异步请求示例

HttpClient client = HttpClient.newHttpClient();
HttpRequest request = HttpRequest.newBuilder().uri(URI.create("https://example.com")).build();client.sendAsync(request, HttpResponse.BodyHandlers.ofString()).thenApply(HttpResponse::body).thenAccept(System.out::println).join(); // 等待完成

WebSocket 支持

HttpClient client = HttpClient.newHttpClient();WebSocket webSocket = client.newWebSocketBuilder().buildAsync(URI.create("ws://example.com/chat"), new WebSocket.Listener() {@Overridepublic void onOpen(WebSocket webSocket) {System.out.println("WebSocket opened");webSocket.sendText("Hello", true);WebSocket.Listener.super.onOpen(webSocket);}@Overridepublic CompletionStage<?> onText(WebSocket webSocket, CharSequence data, boolean last) {System.out.println("Received message: " + data);return WebSocket.Listener.super.onText(webSocket, data, last);}}).join();

高级特性

1. 多部分请求

String boundary = "boundary";
HttpRequest request = HttpRequest.newBuilder().header("Content-Type", "multipart/form-data; boundary=" + boundary).POST(HttpRequest.BodyPublishers.ofByteArrays(Arrays.asList("--boundary\r\nContent-Disposition: form-data; name=\"field1\"\r\n\r\nvalue1\r\n".getBytes(),"--boundary\r\nContent-Disposition: form-data; name=\"file\"; filename=\"test.txt\"\r\nContent-Type: text/plain\r\n\r\nFile content\r\n".getBytes(),"--boundary--\r\n".getBytes()))).build();

2. 处理响应流

HttpRequest request = HttpRequest.newBuilder().uri(URI.create("https://example.com/large-file")).build();HttpResponse<InputStream> response = client.send(request, HttpResponse.BodyHandlers.ofInputStream());try (InputStream is = response.body()) {// 处理输入流byte[] buffer = new byte[8192];int bytesRead;while ((bytesRead = is.read(buffer)) != -1) {// 处理数据块}
}

3. 请求拦截器

HttpClient client = HttpClient.newBuilder().executor(Executors.newFixedThreadPool(5)).authenticator(new Authenticator() {@Overrideprotected PasswordAuthentication getPasswordAuthentication() {return new PasswordAuthentication("user", "password".toCharArray());}}).build();