threadedserver.java

SSD8练习1答案

import java.io.*;
import java.net.*;
import java.util.Date;
import java.util.StringTokenizer;

public class ThreadedServer {
	
	/*the standard input stream*/
	private static BufferedReader stdIn = 
		new BufferedReader(new InputStreamReader(System.in));
	
	/*the standard output stream*/
	private static PrintWriter stdOut =
		new PrintWriter(System.out,true);
	
	/*the default socket port*/
	private static final int port = 8000;
	
	private ServerSocket serverSocket;
	
	static String hostname = null;
	
	/**the constructor of the ThreadedServer
	 * */
	public ThreadedServer(String h) throws IOException {
		
		serverSocket = new ServerSocket(port);
		stdOut.println("Server " + h + "is listening to your request:");
		stdOut.flush();
	}
	
	/**
	 * @param creat a socket object and a thread for 
	 * accepting more than one client's request*/
	public void service() {
		while(true) {
			Socket socket = null;
			try {
				socket = serverSocket.accept();
				Thread serverThread = new Thread(new Handler(socket,hostname));
				serverThread.start();
			} catch(IOException e) {
				e.getMessage().toString();	
			}
		}
	}
	
	public static void main(String args[]) throws IOException{
		stdOut.print("Input the server's name:");
		stdOut.flush();
		hostname = stdIn.readLine();
		new ThreadedServer(hostname).service();
	}
}

	class Handler  implements Runnable {
		/*standard input stream*/
		private static BufferedReader stdIn = 
			new BufferedReader(new InputStreamReader(System.in));
	
		/*standard output stream*/
		private static PrintWriter stdOut = 
			new PrintWriter(System.out,true);
	
		/*the default port number*/
		static final int DEFAULT_PORT = 8000;
	
		/*the port number request by the client*/
		private int port = 0;
	
		/*a identifier shows the request from the client is legal*/
		static final int SUCCESS = 200;
	
		/*a identifier shows the request from the client is illegal*/
		static final int FAILED = 400;
	
		/*a variable shows the request is legal or not*/
		static String responseState = 200 + " OK";
	
		/*a client socket*/
		Socket client;
	
		/*the server's name*/
		static String hostname = null;
	
		/*the response time */
		static Date responseTime;
	
		/*the code name of the erro when the client send a bad request*/
		static String ERRO = "";
	
		public Handler(Socket socket,String h) {
			hostname = h;
			client = socket;
		}
	
		public void response(String fileType,long fileLength,FileReader file) throws Exception {
		
			DataOutputStream outToClient = 
				new DataOutputStream(client.getOutputStream());
			String sendToClient = null;
			String content = null;
			if(fileType == "text/html" || fileType == "txt") {
				int i = 0;
				while(i<fileLength) {
					content += (char)file.read();
					i++;
				}
			}
		
			sendToClient = "HTTP/1.0 " + responseState + "\n"
						+"Server: " + hostname + "\n"
						+"Date: " + responseTime + "\n"
						+"Content-Type: " + fileType + "\n"
						+"Content-Length: " + fileLength + "\n"
						+"Expires: " + new Date() + "\n"//the time the response end
						+ERRO+"Via: " + hostname + " "+DEFAULT_PORT+"\n"
						+"Connection: close\n\n";
			sendToClient += content;
		
			outToClient.writeBytes(sendToClient);
		}
		
		/**
		 * @param send the information which is requested by the client*/
		public void sendMessage() {
			String fileType = null;
			String newUrl = null;
			long fileLength = 0;
			boolean containFile = false;
			FileReader file = null;
			
				try {
					BufferedReader inFromClient =
						new BufferedReader(new InputStreamReader(client.getInputStream()));
					
					//the request from the client
					String command = inFromClient.readLine();
					StringTokenizer request= new StringTokenizer(command);
					
					command = request.nextToken();
					responseState = FAILED + " Bad Request";
					responseTime = new  Date();
					ERRO = "X_" + hostname +"ERR_INVALID_REQ 0\n";
					if(command.equals("GET")) {
						
						String url = "";
						//the path of the file which the client request
						if(request.countTokens() != 2) {
							url = "";
						} else {
							url = request.nextToken();
						}
						if(url.startsWith("/")) {
							request = new StringTokenizer(url,"/");
							newUrl = request.nextToken();
							while(request.hasMoreTokens()) {
									newUrl = newUrl + "\\" + request.nextToken();
						}
						if(newUrl.endsWith(".html")) {
							fileType = "text/html";
							responseTime = new  Date();
							containFile = true;
						} else if(newUrl.endsWith(".jpg")) {
							fileType = "image/jpeg";
							responseTime = new  Date();
							containFile = true;
						} else if(newUrl.endsWith(".gif")) {
							fileType = "image/gif";
							responseTime = new  Date();
							containFile = true;
						} else if(newUrl.endsWith(".txt")) {
							fileType = "txt";
							responseTime = new  Date();
							containFile = true;
						} 
					}
						
						try {
							File f = new File(newUrl);
							fileLength = f.length();
							//stdOut.println(fileLength);
							//stdOut.println(newUrl);
							file = new FileReader(newUrl);  
							stdOut.flush();
							if(containFile == true) {
								responseState = SUCCESS + " OK";
								responseTime = new  Date();
								ERRO = "";
							}
						} catch(Exception e) {
								e.toString();
								//stdOut.println("The file is not existent!");
								stdOut.flush();
						}
					} 
					this.response(fileType,fileLength,file);
					client.close();
				} catch (Exception e) {
					e.toString();
				}
			}
		public void run(){
			
			this.sendMessage();
		}
}