java使用套接字发送文件

我正在尝试使用Java将文件从一台计算机发送到另一台计算机。 我已经编写了下面的代码，如果发送方和接收方都在同一台计算机上启动，但如果它们在不同的机器上工作，则接收文件大小比原始文件大，并且它已损坏，它可以正常工作。

注意：我正在尝试传输最大10 MB的文件。

我怎样才能解决这个问题？

发件人：

ServerSocket server_socket = new ServerSocket(8989); File myFile = new File(myPath); Socket socket = server_socket.accept(); int count; byte[] buffer = new byte[1024]; OutputStream out = socket.getOutputStream(); BufferedInputStream in = new BufferedInputStream(new FileInputStream(myFile)); while ((count = in.read(buffer)) > 0) { out.write(buffer, 0, count); out.flush(); } socket.close(); 

接收器：

 Socket socket = new Socket(address, 8989); FileOutputStream fos = new FileOutputStream(anotherPath); BufferedOutputStream out = new BufferedOutputStream(fos); byte[] buffer = new byte[1024]; int count; InputStream in = socket.getInputStream(); while((count=in.read(buffer)) >0){ fos.write(buffer); } fos.close(); socket.close(); 

Answer 1

在客户端，你写入count字节并发送它们：

 while ((count = in.read(buffer)) > 0) { out.write(buffer, 0, count); 

在服务器端，您读取count字节 – 但然后您将整个缓冲区写入文件！

 while((count=in.read(buffer)) > 0){ fos.write(buffer); 

只需将其更改为：

 fos.write(buffer, 0, count); 

你会安全的。 BTW你的程序有另一个小错误： read()可以返回0 ，这并不意味着InputStream结束。 使用>=代替：

 count = in.read(buffer)) >= 0 

---

你有没有考虑IOUtils.copy(InputStream, OutputStream) Apache Commons的IOUtils.copy(InputStream, OutputStream) ？ 它会减少你的整个while循环：

 OutputStream out = socket.getOutputStream(); InputStream in = new FileInputStream(myFile); IOUtils.copy(in, out); socket.close(); 

编写的代码更少，测试的代码更少。 缓冲是在内部完成的。

Answer 2

请记住， in.read(buffer)不一定用新数据填满整个缓冲区。 因此，您应该确保不写入整个缓冲区。 更改

 while((count=in.read(buffer)) >0){ fos.write(buffer); } 

至

 while((count=in.read(buffer)) >0){ fos.write(buffer, 0, count); } 

Answer 3

寄件人

 Socket sock = new Socket("127.0.0.1", 5991); System.out.println("Connecting........."); File myFile = new File("/root/qrcode/"); File[] files = myFile.listFiles(); OutputStream os = sock.getOutputStream(); BufferedOutputStream bos = new BufferedOutputStream(os); DataOutputStream dos = new DataOutputStream(bos); dos.writeInt(files.length); long totalBytesRead = 0; int percentCompleted = 0; for(File file : files) { long length = file.length(); dos.writeLong(length); String name = file.getName(); dos.writeUTF(name); FileInputStream fis = new FileInputStream(file); BufferedInputStream bis = new BufferedInputStream(fis); int theByte = 0; while((theByte = bis.read()) != -1) { totalBytesRead += theByte; bos.write(theByte); } // System.out.println("file read"); bis.close(); } dos.close(); //Closing socket sock.close(); 

接收器

 ServerSocket serverSocket = new ServerSocket(5991); while(true) { Socket clientSocket = null; System.out.println("Starting..."); clientSocket = serverSocket.accept(); InputStream in = clientSocket.getInputStream(); //used BufferedInputStream bis = new BufferedInputStream(in); String dirPath ; dirPath = "/root/NewFolder"; try{ DataInputStream dis = new DataInputStream(bis); int filesCount = dis.readInt(); File[] files = new File[filesCount]; long f_l = 0; int count =0 ; long totalBytesRead = 0; int percentCompleted = 0; for(int i = 0; i < filesCount; i++) { long fileLength = dis.readLong(); String fileName = dis.readUTF(); f_l = f_l +fileLength; files[i] = new File(dirPath + "/" + fileName); FileOutputStream fos = new FileOutputStream(files[i]); BufferedOutputStream bos = new BufferedOutputStream(fos); int tot = 0; for(int j = 0; j < fileLength; j++) { bos.write(bis.read()); } bos.close(); } }catch(Exception ex) { System.out.println("error in socket programming "); } }