第十三章 網路檔案傳遞(File Transition)   13-1 簡介 13-2 FileInputStream Class 13-3 FileOutputStream Class 13-4 檔案傳遞(File Translation) 13-5 檔案上傳(File Upload) 13-6 檔案下載(File Download) 13-7 習題(Exercises)

13-1 簡介   前章網路訊息傳遞，是為小宗串流傳遞，本章將介紹網路檔案傳遞，是為大宗串流傳遞。除了要使用網路資料串流外，另外要使用本機當地資料串流，讀取檔案內的資料、或將資料寫入檔案。

13-2 FileInputStream Class   java.io.FileInputStream繼承(extends) 自InputStream→Object，此類別從檔案建立一個低階輸入串流，使用其中之方法程序讀取檔案內容。

13-3 FileOutputStream Class java.io.FileOutputStream繼承(extends) 自OutputStream→Object，此類別建立一個低階輸出串流，使用其中之方法程序將串流內容寫入指定檔案。

13-4 檔案傳遞(File Translation)   設計範例130，於Client端讀取特定檔案的內容，再由網路將內容傳送到Server端之特定檔案內。

範例130：設有檔案Server13_4.java、Client13_4.java其功能為解釋檔案傳遞之應用。   檔案Server13_4.java： 01 import java.net.*; 02 import java.io.*; 03 public class Server13_4 { 04 int messagein; 05 static int port; 06 static String outfilename; 07 public Server13_4() { 08 try{ 09 ServerSocket SS = new ServerSocket(port); 10 System.out.println("Server is created and waiting Client to connect..."); 11 Socket socket = SS.accept(); 12 System.out.println("Client IP = " + socket.getInetAddress().getHostAddress());

範例130：續1 13 DataInputStream instream = new DataInputStream(socket.getInputStream()); 14 FileOutputStream fos = new FileOutputStream(outfilename);   15 while(messagein != -1){ 16 messagein = instream.readInt(); 17 fos.write(messagein); 18 } 19 System.out.println("Data written to File successfully!"); 20 } 21 catch(IOException e){ 22 System.out.println(e.getMessage()); 23 } 24 }

範例130：續2 25 public static void main(String args[]){ 26 if(args.length < 2){ 27 System.out.println("Usage: java Server13_4 [port] [outfilename]"); 28 System.exit(1); 29 } 30 port=Integer.parseInt(args[0]); 31 outfilename = args[1]; 32 Server13_4 ServerStart=new Server13_4(); 33 } 34 }

範例130：續3 檔案Client13_4.java： 35 import java.io.*; 36 import java.net.*;   37 public class Client13_4 { 38 int i; 39 static String iaddr; 40 static int port; 41 static String infilename; 42 public Client13_4() { 43 try{ 44 Socket socket=new Socket(InetAddress.getByName(iaddr),port); 45 DataOutputStream outstream = new DataOutputStream(socket.getOutputStream()); 46 FileInputStream fis = new FileInputStream(infilename);

範例130：續4 47 while((i=fis.read()) !=-1) outstream.writeInt(i);   49 System.out.println("Data sent to internet successfully!"); 50 socket.close(); 51 } 52 catch(IOException e){ 53 System.out.println(e.getMessage()); 54 } 55 }

範例130：續5 56 public static void main(String args[]) { 57 if (args.length < 3){ 58 System.out.println("USAGE: java Client13_4 [iaddr] [port] [infilename]"); 59 System.exit(1); 60 }   61 iaddr = args[0]; 62 port=Integer.parseInt(args[1]); 63 infilename = args[2]; 64 Client13_4 ClientStart=new Client13_4(); 65 } 66 }

13-5 檔案上傳(File Upload)   設計範例131，從Client端將特定檔案由網路上傳(Upload) 到Server端所在目錄內。也即、當要對特定檔案執行網路上傅時，將本例Client.class置於該特定檔案所在目錄，再將本例Server.class置於遠端目的目錄，依執行步驟即可上傳該特定檔案。

範例131：設有檔案Server_upload.java、Client_upload.java其功能為解釋檔案上傳之應用。   檔案Server_upload.java： 01 import java.net.*; 02 import java.io.*; 03 public classServer_upload { 04 static int port; 05 static String uploadFile; 06 int messagein; 07 public Server_upload() { 08 try{ 09 ServerSocket SS = new ServerSocket(port); 10 System.out.println("Server_upload is ready..."); 11 Socket cmdsocket = SS.accept(); 12 Socket datasocket = SS.accept();

範例131：續1 13 System.out.println("Client IP = " + cmdsocket.getInetAddress().getHostAddress()); 14 DataInputStream cmdinstream = new DataInputStream(cmdsocket.getInputStream()); 15 uploadFile = cmdinstream.readUTF();   16 DataInputStream datainstream = new DataInputStream(datasocket.getInputStream()); 17 FileOutputStream fos = new FileOutputStream(uploadFile); 18 while(messagein != -1){ 19 messagein = datainstream.readInt(); 20 fos.write(messagein); 21 } 22 System.out.println("File is uploaded successfully!"); 23 }

範例131：續2 24 catch(IOException e){ 25 System.out.println(e.getMessage()); 26 } 27 }   28 public static void main(String args[]){ 29 if(args.length < 1){ 30 System.out.println("Usage: java Server_upload [port]"); 31 System.exit(1); 32 } 33 port = Integer.parseInt(args[0]); 34 Server_upload ServerStart=new Server_upload(); 35 } 36 }

範例131：續3 檔案Client_upload.java： 37 import java.io.*; 38 import java.net.*;   39 public class Client_upload { 40 int i; 41 static String iaddr; 42 static int port; 43 static String uploadFile; 44 public Client_upload() { 45 try{ 46 Socket cmdsocket=new Socket(InetAddress.getByName(iaddr),port); 47 Socket datasocket=new Socket(InetAddress.getByName(iaddr),port);

範例131：續4 48 DataOutputStream cmdoutstream = new DataOutputStream(cmdsocket.getOutputStream()); 49 cmdoutstream.writeUTF(uploadFile);   50 DataOutputStream dataoutstream = new DataOutputStream(datasocket.getOutputStream()); 51 FileInputStream fis = new FileInputStream(uploadFile); 52 while((i=fis.read()) !=-1) dataoutstream.writeInt(i); 53 dataoutstream.writeInt(i); 54 System.out.println("File is sent to internet successfully!"); 55 cmdsocket.close(); 56 datasocket.close(); 57 }

範例131：續5 58 catch(IOException e){ 59 System.out.println(e.getMessage()); 60 } 61 }   62 public static void main(String args[]) { 63 if (args.length < 3){ 64 System.out.println("USAGE: java Client_upload [iaddr] [port] [uploadFile]"); 65 System.exit(1); 66 } 67 iaddr = args[0]; 68 port=Integer.parseInt(args[1]); 69 uploadFile = args[2]; 70 Client_upload ClientStart=new Client_upload(); 71 } 72 }

13-6 檔案下載(File Download)   設計範例132，從Client端對Server端所在目錄內之檔案執行下載(Download)。也即、當要對特定檔案執行網路下載時，將本例Client.class置於需求目錄內，再將本例Server.class置於遠端檔案群目錄內，依執行步驟從Client端對Server端目錄內之特定檔案執行下載。

範例132：設有檔案Server_download.java、Client_download.java其功能為解釋檔案下載之應用。   檔案Server_download.java： 01 import java.net.*; 02 import java.io.*; 03 public class Server_download { 04 static int port; 05 static String downloadFile; 06 int messagein, i; 07 public Server_download() { 08 try{ 09 ServerSocket SS = new ServerSocket(port); 10 System.out.println("Server_download is ready...");

範例132：續1 11 Socket cmdsocket = SS.accept(); 12 Socket datasocket = SS.accept();   13 System.out.println("Client IP = " + cmdsocket.getInetAddress().getHostAddress()); 14 DataInputStream cmdinstream = new DataInputStream(cmdsocket.getInputStream()); 15 downloadFile = cmdinstream.readUTF(); 16 DataOutputStream dataoutstream = new DataOutputStream(datasocket.getOutputStream()); 17 FileInputStream fis = new FileInputStream(downloadFile); 18 while((i=fis.read()) !=-1) 19 dataoutstream.writeInt(i); 20 dataoutstream.writeInt(i);

範例132：續2 21 System.out.println("File is sent to internet successfully!"); 22 datasocket.close(); 23 cmdsocket.close(); 24 } 25 catch(IOException e){ 26 System.out.println(e.getMessage()); 27 } 28 }   29 public static void main(String args[]){ 30 if(args.length < 1){ 31 System.out.println("Usage: java Server_download [port]"); 32 System.exit(1); 33 } 34 port=Integer.parseInt(args[0]); 35 Server_download ServerStart=new Server_download(); 36 } 37 }

範例132：續3 檔案Client_download.java： 38 import java.io.*; 39 import java.net.*;   40 public class Client_download { 41 int i; 42 static String iaddr; 43 static int port; 44 static String downloadFile; 45 int messagein; 46 public Client_download() { 47 try{ 48 Socket cmdsocket=new Socket(InetAddress.getByName(iaddr),port); 49 Socket datasocket=new Socket(InetAddress.getByName(iaddr),port);

範例132：續4 50 DataOutputStream cmdoutstream = new DataOutputStream(cmdsocket.getOutputStream()); 51 cmdoutstream.writeUTF(downloadFile);   52 DataInputStream datainstream = new DataInputStream(datasocket.getInputStream()); 53 FileOutputStream fos = new FileOutputStream(downloadFile); 54 while(messagein != -1){ 55 messagein = datainstream.readInt(); 56 fos.write(messagein); 57 } 58 System.out.println("File is downloaded successfully!"); 59 cmdsocket.close(); 60 datasocket.close(); 61 }

範例132：續5 62 catch(IOException e){ 63 System.out.println(e.getMessage()); 64 } 65 }   66 public static void main(String args[]) { 67 if (args.length < 3){ 68 System.out.println("USAGE: java Client_download [iaddr] [port] [downloadFile]"); 69 System.exit(1); 70 } 71 iaddr = args[0]; 72 port=Integer.parseInt(args[1]); 73 downloadFile = args[2]; 74 Client_download ClientStart=new Client_download(); 75 } 76 }