在Java中，上傳文件到文件服務器通常可以通過多種方式實現，例如使用`HttpURLConnection`進行HTTP POST請求，或者使用第三方庫如Apache HttpClient、OkHttp等。以下是一個使用`HttpURLConnection`上傳文件的簡單示例：

```java

import java.io.;

import java.net.HttpURLConnection;

import java.net.URL;

public class FileUploader {

public static void uploadFile(String targetUrl, File file) throws IOException {

URL url = new URL(targetUrl);

HttpURLConnection httpConn = (HttpURLConnection) url.openConnection();

httpConn.setDoOutput(true);

httpConn.setDoInput(true);

httpConn.setRequestProperty("Content-Type", "multipart/form-data");

httpConn.setRequestProperty("Content-Length", String.valueOf(file.length()));

httpConn.setRequestProperty("Content-Disposition", "form-data; name="file"; filename="" + file.getName() + """);

httpConn.setRequestProperty("Connection", "Keep-Alive");

httpConn.setRequestMethod("POST");

try (OutputStream out = httpConn.getOutputStream()) {

Files.copy(file.toPath(), out);