BÀi thực hành số 11 Mục tiêu
tải về 55.42 Kb.
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- Điều hướng trang này:
- Các bước thực hiện Xây dựng giao thức đơn giản
- Soạn thảo tập tin FileServer.java
- ServerSocket server_socket = ...
- Socket client_socket = ...
- Soạn thảo tập tin Worker.java
- BufferedReader in = new BufferedReader (isr); // Now get an output stream to the client. OutputStream os = ...
- PrintWriter out = new PrintWriter (osr, true); while (true) { // First read the message from the client String str = in.readLine ();
- FileOutStream file_out = new FileOutputStream (file_name);
- Soạn thảo tập tin FileClient.java
- Thực thi FileClient C:\bai1> javac FileClient.java C:\bai1> java FileClient Bài tập
- Về việc nộp bài thực hành
Khoa Khoa học & Kỹ thuật Máy tính, trường Đại Học Bách Khoa – ĐHQG Tp.HCM BÀI THỰC HÀNH SỐ 11
import java.net.*; import java.io.*; import java.util.*; public class FileServer { public static void main (String argv[]) throws IOException { int port = 8000; // server port number // Create a ServerSocket object ServerSocket server_socket = ... System.out.println ("Server started"); // Loop indefinitely while waiting for clients to connect while (true) { // accept () does not return until a client requests a connection Socket client_socket = ... // Now that a client has arrived, create an instance of our special // thread subclass to respond to it. Worker worker = new Worker (client_socket); ... System.out.println ("New client connected"); } } // main } // class FileServer
import java.net.*; import java.io.*; import java.util.*;
class Worker extends Thread { Socket socket = null; /** Pass the socket as a argument to the constructor **/ Worker ( Socket client_socket ) throws SocketException {
// will be responsive to new clients. setPriority ( NORM_PRIORITY - 1 ); }
* This thread receives a message from the client that will * request a web page file. The file name is found relative to * the directory location of this code. **/
public void run () { try {
// Use the client socket to obtain an input stream from it. InputStream is = ... // For text input we wrap an InputStreamReader around // the raw input stream and set ASCII character encoding. InputStreamReader isr = new InputStreamReader (is, "8859_1"); // Finally, use a BufferReader wrapper to obtain // buffering and higher order read methods.
// the raw output stream and set ASCII character encoding. OutputStreamWriter osr = new OutputStreamWriter (os, "8859_1"); // Finally, we use a PrintWriter wrapper to obtain its // higher level output methods.Open in autoflush mode. // (Autoflush occurs only with println() method.)
{ // First read the message from the client String str = in.readLine (); System.out.println ("Client message: " + str); // Example: GET example.txt // Split the message into substrings. String [] tokens = str.split(" ");
tokens[0].equals ("QUIT")) { ... }
// and that the first word is the GET command. if ((tokens.length >= 2) && tokens[0].equals ("GET")) { String file_name = tokens[1]; // Now read the file from the disk and write it to the // output stream to the client. try {
FileInputStream file_in = new FileInputStream (file_name); // Send the header. out.println("200 OK\r\n"); File file = new File (file_name); out.println("Content-length: " + file_in.available () + "\r\n"); // Creat a byte array to hold the file. byte [] data = new byte [file_in.available ()]; file_in.read (data); // Read file into the byte array os.write (data); // Write it to client output stream os.flush (); // Remember to flush output buffer file_in.close (); // Close file input stream } catch (FileNotFoundException e) { // If no such file, then send the 201 message. out.println ("201 File Not Found" ); } //} // Check that the message has a minimun number of words // and that the first word is the GET command. //else if ((tokens.length >= 2) && // tokens[0].equals ("PUT")) { //String file_name = tokens[1];
//try {
// Open a stream to the file. //FileOutStream file_out = new FileOutputStream (file_name); //... //} catch (FileNotFoundException e) { // out.println ("202 File Existed" ); //}
} else { out.println ("203 Bad Request"); } } catch (FileNotFoundException e) { out.println ("202 File Existed"); } catch (IOException e) { System.out.println ( "I/O error " + e ); } } // End while // Close client socket. try {
... } catch (IOException e){ System.out.println ("I/O error " + e ); } // On return from run () the thread process will stop. } // run } // class Worker
C:\bai2> javac Worker.java FileServer.java C:\bai1> java FileServer
telnet 127.0.0.1 8000 GET example.txt
import javax.swing.*; import java.awt.*; import java.awt.event.*; import java.io.*; import java.net.*;
* This program provides a graphical user interface to * set up the connection to a server and to download/upload * the file from/to the server. **/ public class ClientClient extends JFrame implements Runnable, ActionListener {
JTextArea fTextArea = null;
JTextField fPortField; JTextField fFileField;
String fIpAddr = "127.0.0.1"; // Default port int fPort = 8000; // Socket to connect with server. Socket fSocket = null; // File name String fFilename = "example.txt"; // Change the button name as needed String fButtonName = "Get"; JButton fButton = null;
public static void main (String [] args) { FileClient f = new FileClient ("Client for FileServer "); f.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE); f.setVisible(true); }
* Create user interface for client. Includes text fields * for the server IP address, the server's port number, a * text area to show the data returned from the server, and * a button to initiate the connection to the server. **/
FileClient (String title){ super (title); Container content_pane = getContentPane (); // Create a user interface. content_pane.setLayout ( new BorderLayout () ); fTextArea = new JTextArea (""); fTextArea.setLineWrap (true); content_pane.add ( fTextArea, "Center"); // Create a panel with three text fields to obtain // the server address, the port number, // the file to download, and to initiate the link // with the server. fIpField = new JTextField (fIpAddr); fPortField = new JTextField (""+fPort); fFileField= new JTextField (fFilename);
fButton = new JButton (fButtonName); fButton.addActionListener (this);
panel.add (fIpField); panel.add (fPortField); panel.add (fFileField); panel.add (fButton); content_pane.add ( panel, "South"); setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE); }
public void actionPerformed ( ActionEvent e ){ boolean status = false; String command = e.getActionCommand ();
fIpAddr = fIpField.getText (); // Get port number fPort = Integer.parseInt (fPortField.getText ()); // Get the name of the file to download fFilename = fFileField.getText (); start (); } } /** * Start the thread to connect to the server * and read the file from it. */ public void start (){ // If the thread reference not null then a // thread is already running. Otherwise, create // a thread and start it. if (fThread == null) { fThread = new Thread (this); fThread.start (); } } // start /** Connect with the server via a thread process. **/ public void run () { // Clear the text area fTextArea.setText ("Downloading..."); try{ // Connect to the server via the given IP address and port number ...
String message = "GET " + fFilename; // Now get an output stream to the server. OutputStream os = ... // Wrap in writer classes PrintWriter pw = new PrintWriter ( new OutputStreamWriter (os, "8859_1"), true );
pw.println (message); // Get the input stream from the server and then // wrap the stream in two wrappers. BufferedReader br = new BufferedReader ( new InputStreamReader ( ... ) ); String line; // Get some first line to get file size ... // Prepare buffer to get data from File Server and save to local file ... fTextArea.setText ("OK"); // Send message QUIT to the server pw.println (“QUIT”); } catch ( UnknownHostException uhe) { fTextArea.setText ("Unknown host"); } catch ( IOException ioe){ fTextArea.setText ("I/O Exception"); } finally{ try{
// End the connection ...
fThread=null; } catch ( IOException ioe) { fTextArea.append ("IO Exception while closing socket"); } } } // run
C:\bai1> javac FileClient.java C:\bai1> java FileClient
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