怎样处理发送POST请求并携带自定义 headers？

在Java中，无论是使用`HttpURLConnection`还是`Apache HttpClient`，发送POST请求并携带自定义headers都很简单，下面是一个例子：

### 使用`HttpURLConnection`:

URL url = new URL("http://example.com/api");
HttpURLConnection connection = (HttpURLConnection) url.openConnection();

// 设置POST请求方法
connection.setRequestMethod("POST");

// 添加自定义header
connection.setRequestProperty("Content-Type", "application/json");
connection.setRequestProperty("Authorization", "Bearer your_token");

// 创建请求体，这里以JSON为例
String requestBody = "{\"key\":\"value\"}";

// 写入请求体
OutputStream outputStream = connection.getOutputStream();
outputStream.write(requestBody.getBytes(StandardCharsets.UTF_8));
outputStream.flush();
outputStream.close();

// 获取响应
try (BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream()))) {
    String inputLine;
    StringBuilder response = new StringBuilder();
    while ((inputLine = in.readLine()) != null) {
        response.append(inputLine);
    }
    System.out.println(response.toString());
}

// 关闭连接
connection.disconnect();

### 使用`Apache HttpClient`:

CloseableHttpResponse response;
HttpPost postRequest = new HttpPost("http://example.com/api");
postRequest.setHeader("Content-Type", "application/json");
postRequest.setHeader("Authorization", "Bearer your_token");

try {
    BasicHttpParams params = new BasicHttpParams();
    HttpClientBuilder clientBuilder = HttpClientBuilder.create(params)
            .setDefaultHeaders(Collections.singletonMap("Content-Type", "application/json"));
    HttpClient httpClient = clientBuilder.build();
    response = httpClient.execute(postRequest, new StringEntity(requestBody));

    // ...处理响应...
} finally {
    // 关闭连接
    response.close();
    httpClient.getConnectionManager().shutdown();
}

在上述示例中，你需要将"your_token"替换为你实际的访问令牌，并确保`requestBody`是你想要发送的数据（这里是JSON格式）。