为什么InputStream.read（）阻塞在这里？

我应该开发一个简单的SFTP。
事情进展顺利，直到我的ByteArrayOutputStream （在这种情况下， baos ）没有编写所有的arrayByte 。 有些人可以向我解释，为什么系统会挂在我身上？

服务器端：

 public static void main (String[] args) { int portTexto = 5656; String comando; String regexGet = "\\s*(get)\\s[A-z0-9]*\\.[A-z0-9]*\\s*"; String regexPut = "\\s*(put)\\s[A-z0-9]*\\.[A-z0-9]*\\s*"; try{ ServerSocket servSockTexto = new ServerSocket(portTexto); // pegar IP de servidor. try { InetAddress addr = InetAddress.getLocalHost(); System.out.println(addr.getHostAddress()); } catch (UnknownHostException e) { } System.out.println("Aguardando conexão com Servidor de Texto..."); Socket sock = servSockTexto.accept(); System.out.println("Conexão com Servidor estabelecida."); //BufferedOutputStream paraCliente = new BufferedOutputStream(sock.getOutputStream()); DataInputStream inputServ = new DataInputStream(sock.getInputStream()); DataOutputStream outputServ = new DataOutputStream(sock.getOutputStream()); BufferedOutputStream paraCliente = new BufferedOutputStream(sock.getOutputStream()); //1 outputServ.writeUTF("Conexão com Servidor estabelecida."); do { //3 comando = inputServ.readUTF(); if(comando.matches(regexGet)) { String[] aux = comando.split("\\s"); String nomeArq = aux[1]; File arqGet = new File(nomeArq); //4 outputServ.writeUTF(arqGet.getName()); byte[] arrayByte = new byte[(int) arqGet.length()]; FileInputStream fInput = new FileInputStream(arqGet); BufferedInputStream bInput = new BufferedInputStream(fInput); bInput.read(arrayByte, 0, arrayByte.length); //5 paraCliente.write(arrayByte.length); //6 paraCliente.write(arrayByte, 0, arrayByte.length); paraCliente.flush(); bInput.close(); fInput.close(); } else if(comando.matches(regexPut)) { } else if (!comando.equals("sair")) { //4 outputServ.writeUTF("Comando não existente."); } } while(!comando.equals("sair")); servSockTexto.close(); sock.close(); inputServ.close(); outputServ.close(); paraCliente.close(); } catch (Exception ex) { System.out.println("Erro: " + ex); } } 

客户端：

  public static void main (String[] args) { String IP = "localhost"; String comando; String regexGet = "\\s*(get)\\s[A-z0-9]*\\.[A-z0-9]*\\s*"; String regexPut = "\\s*(put)\\s[A-z0-9]*\\.[A-z0-9]*\\s*"; int portTexto = 5656; Scanner scan = new Scanner(System.in); try{ Socket sock = new Socket (IP,portTexto); //BufferedInputStream is = new BufferedInputStream(sock.getInputStream()); DataInputStream inputCli = new DataInputStream(sock.getInputStream()); DataOutputStream outputCli = new DataOutputStream(sock.getOutputStream()); InputStream is = sock.getInputStream(); //BufferedInputStream is = new BufferedInputStream(sock.getInputStream()); //1 System.out.println(inputCli.readUTF()); do { System.out.println("Digite um comando:"); comando = scan.nextLine(); //3 outputCli.writeUTF(comando); if(comando.matches(regexGet)) { //4 String arqTeste = "C:\\Users\\Frederico\\Desktop\\Download SFTP\\" + inputCli.readUTF(); int bytesRead; ByteArrayOutputStream baos = new ByteArrayOutputStream(); FileOutputStream fos = new FileOutputStream( arqTeste ); BufferedOutputStream bos = new BufferedOutputStream(fos); //5 byte[] aByte = new byte[1]; //6 bytesRead = is.read(aByte, 0, aByte.length); // MY SYSTEM STAYS INSIDE THIS DO AND I CANT SOLVE THIS!!! do { baos.write(aByte); bytesRead = is.read(aByte); } while (bytesRead != -1); //is.close(); bos.write(baos.toByteArray()); bos.flush(); bos.close(); } else if(comando.matches(regexPut)) {} else if (!comando.equals("sair")) { //4 System.out.println(inputCli.readUTF()); } } while(!comando.equals("sair")); is.close(); sock.close(); inputCli.close(); outputCli.close(); System.out.println("Conexão com servidor encerrada."); } catch (Exception ex) { System.out.println("Erro: " + ex); } } 

Answer 1

您的do/while循环运行直到流结束，但对等方永远不会关闭套接字。 该协议似乎需要保持套接字打开以进一步命令，因此您必须调整它的这一部分以包含长度字前缀，以便您知道要复制多少字节。

问题不在于ByteArrayOutputStream没有写入所有字节，而是在is.read()阻塞。