public class UplaodServer {
  public static void main(String []args){
    try(
      // 創(chuàng)建一個(gè)ServerSocket監(jiān)聽8080端口的請(qǐng)求
      // ServerSocket 實(shí)現(xiàn)了 AutoCloseable接口, 可以自動(dòng)釋放資源
    	ServerSocket server = new ServerSocket(8080);
      // accept()會(huì)阻塞當(dāng)前線程, 等待客戶端請(qǐng)求 
      Socket socket = server.accept();
      // 獲取輸入流
      BufferedInputStream in = new BufferedInputStream(socket.getInputStream());
      // 由文件輸出流創(chuàng)建緩沖輸出流, 寫入本地upload.jpg 文件
      FileOutputStream outputStream = new FileOutputStream("./upload.jpg")
    ){
      // 緩沖區(qū) 
      byte [] buffer = new byte[1024];
      int len = in.read(buffer);
      while(len != -1){
        // 寫入數(shù)據(jù)到文件
        outputStream.write(buffer, 0, len);
        // 再次從Socket中讀取數(shù)據(jù)
        len = in.read(buffer);
      }
      System.out.println("文件已上傳");
    }catch (IOException e) {
      e.printStackTrace();
    }
  }
}

public class UploadClient {
  public static void main(String []args){
    try(
    	// Socket 實(shí)現(xiàn)了 AutoCloseable接口 可自動(dòng)關(guān)閉資源
      Socket socket = new Socket("127.0.0.1", 8080);
       // 又Socket獲得輸出流， 并創(chuàng)建緩沖輸出流
      BufferedOutputStream out = new BufferedOutputStream(socket.getOutputStream());
      FileInputStream fileInput = new FileInputStream("F:\file\oxx6j5.jpg");
      // 由文件輸入流創(chuàng)建緩沖輸入流
      BufferedInputStream in = new BufferedInputStream(fileInputStream);
    ){
       // 準(zhǔn)備緩沖區(qū)
      byte[] buffer = new byte[1024];
      int len = in.read(buffer);
      while (len != -1) {
        // 寫入Socket
        out.write(buffer, 0, len);
        // 再次讀取文件
        len = in.read(buffer);
      }
      System.out.println("上傳成功！");
    }catch (ConnectException e) {
      System.out.println("服務(wù)器未啟動(dòng)");
      e.printStackTrace();
    } catch (IOException e) {
      e.printStackTrace();
    }
  }
}