java 上传文件远程调用

### Java实现文件上传的远程接口调用 在Java中，可以通过多种方式实现文件上传的远程接口调用。以下是基于`Socket`和`RESTful API`两种常见的方式。 #### 使用Socket实现文件上传 通过`Socket`可以实现在客户端和服务端之间传输数据的功能。下面是一个简单的示例： ```java // 客户端代码 import java.io.*; import java.net.Socket; public class FileUploadClient { public static void main(String[] args) throws IOException { String serverAddress = "localhost"; int port = 8080; try (Socket socket = new Socket(serverAddress, port); OutputStream out = socket.getOutputStream(); FileInputStream fis = new FileInputStream("example.txt")) { byte[] buffer = new byte[4096]; int bytesRead; while ((bytesRead = fis.read(buffer)) != -1) { out.write(buffer, 0, bytesRead); // 将文件内容写入到Socket流中[^2] } } catch (IOException e) { System.out.println("Error uploading file: " + e.getMessage()); } } } ``` 服务端接收文件并保存： ```java // 服务端代码 import java.io.*; import java.net.ServerSocket; import java.net.Socket; public class FileUploadServer { public static void main(String[] args) throws IOException { int port = 8080; ServerSocket serverSocket = new ServerSocket(port); try (Socket clientSocket = serverSocket.accept(); // 接受客户端连接 InputStream in = clientSocket.getInputStream(); FileOutputStream fos = new FileOutputStream("received_example.txt")) { byte[] buffer = new byte[4096]; int bytesRead; while ((bytesRead = in.read(buffer)) != -1) { fos.write(buffer, 0, bytesRead); // 将接收到的数据写入本地文件 } } finally { serverSocket.close(); } } } ``` --- #### 使用RESTful API实现文件上传 对于现代应用开发，通常推荐使用HTTP协议并通过`RESTful API`完成文件上传功能。以下是一个基于Spring Boot框架的简单示例。 ##### Spring Boot服务端配置 创建一个控制器用于处理文件上传请求： ```java @RestController @RequestMapping("/upload") public class FileUploadController { @PostMapping(consumes = MediaType.MULTIPART_FORM_DATA_VALUE) public ResponseEntity<String> uploadFile(@RequestParam("file") MultipartFile file) { if (!file.isEmpty()) { try { // 获取目标路径 Path path = Paths.get("uploads/" + file.getOriginalFilename()); // 将文件保存至指定位置 Files.copy(file.getInputStream(), path, StandardCopyOption.REPLACE_EXISTING); return ResponseEntity.ok("File uploaded successfully!"); } catch (Exception e) { return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).body(e.getMessage()); } } else { return ResponseEntity.badRequest().body("Please select a file to upload."); } } } ``` ##### 客户端发送文件 利用`HttpClient`或其他工具向服务端发起POST请求： ```java import org.apache.http.HttpEntity; import org.apache.http.client.methods.CloseableHttpResponse; import org.apache.http.client.methods.HttpPost; import org.apache.http.entity.ContentType; import org.apache.http.entity.mime.MultipartEntityBuilder; import org.apache.http.impl.client.CloseableHttpClient; import org.apache.http.impl.client.HttpClients; import java.io.File; public class RestFileUploader { public static void main(String[] args) throws Exception { CloseableHttpClient httpClient = HttpClients.createDefault(); HttpPost post = new HttpPost("http://localhost:8080/upload"); File file = new File("example.txt"); HttpEntity entity = MultipartEntityBuilder.create() .addBinaryBody("file", file, ContentType.APPLICATION_OCTET_STREAM, file.getName()) .build(); post.setEntity(entity); try (CloseableHttpResponse response = httpClient.execute(post)) { System.out.println(response.getStatusLine().getStatusCode() + ": " + response.getStatusLine().getReasonPhrase()); } } } ``` 上述代码展示了如何通过`Multipart/form-data`形式提交文件给服务端[^4]。 --- ### 总结 以上分别介绍了基于`Socket`和`RESTful API`的文件上传方案。前者适合低层通信需求场景；后者则更适用于现代化Web应用程序开发环境下的文件传输操作。