用Socket实现的多线程类邮件服务器，朋友的一个作业题

一个朋友的作业，用Socket实现简单的邮件功能，客户端和服务器端。

 

 

Computer and Communication Networks(CSIS0234B)
Assigment 1: Simple Mail Service
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file list
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MailServer.java
MailClient.java
readme.txt

Key feature
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1 Server support multi-threads of client
2 Support multi message from client for same user

 
Support command
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#USERNAME username of user
#PASSWORD password of user
#SENDTO  username send to;
#TITLE  title of message send to
#CONTENT content of message send to
#RECEIVE receive message current user logined
#EXIT exit the system

 

 

 

服务器端：

import java.io.BufferedReader;import java.io.BufferedWriter;import java.io.File;import java.io.FileReader;import java.io.FileWriter;import java.io.IOException;import java.io.InputStreamReader;import java.io.OutputStreamWriter;import java.net.ServerSocket;import java.net.Socket;import java.util.HashMap;import java.util.Map;/** * 简单服务器端的实现。<br> * 多线程。 * * @author 老紫竹(laozizhu.com) */public class MailServer { public static void main(String[] args) throws IOException { ServerSocket server = null; try { // We assume that our service port number is 1234 server = new ServerSocket(1234); while (true) { try { new MailServerThread(server.accept()).start(); } catch (IOException e) { System.out.println("Accept failed: 1234"); } catch (Exception e) { System.out.println("Server error:" + e.getMessage()); } } } catch (IOException e) { System.out.println("Failed to listen on port: 1234"); } finally { if (server != null) { server.close(); } } }}class MailServerThread extends Thread { // common string private static final String OK = "250"; private static final String ERROR = "200"; private static final String BR = "/r/n"; private static final String FILEPATH = "Mailbox and client information/"; private static final String FILENAME_EXT = ".txt"; private static final String FILENAME_CLIENTINFO = FILEPATH + "ClientInfo.txt"; // command private static final String COMMAND_USERNAME = "#USERNAME"; private static final String COMMAND_PASSWORD = "#PASSWORD"; private static final String COMMAND_SENDTO = "#SENDTO"; private static final String COMMAND_TITLE = "#TITLE"; private static final String COMMAND_CONTENT = "#CONTENT"; private static final String COMMAND_RECEIVE = "#RECEIVE"; private static final String COMMAND_EXIT = "#EXIT"; // message private static final String MESSAGE_EXIT = OK + " Exit ok" + BR; private static final String MESSAGE_COMMAND_NOT_FOUND = ERROR + " Command not found"; private static final String MESSAGE_AUTH_NEED = ERROR + " User not logged in yet"; private static final String MESSAGE_USERNAME_OK = OK + " Username ok"; private static final String MESSAGE_USERNAME_NOT_EXISTS = ERROR + " Username is not exists"; private static final String MESSAGE_USERNAME_COMMAND_FIRST = ERROR + " " + COMMAND_USERNAME + " first!"; private static final String MESSAGE_USER_AUTH_OK = OK + " User authenticated"; private static final String MESSAGE_USER_AUTH_ERROR = ERROR + " Authentication failure"; private static final String MESSAGE_SENDTO_MISSION = ERROR + " Recipient error"; private static final String MESSAGE_SENDTO_NOT_EXISTS = ERROR + " Recipient does not exist on the server"; private static final String MESSAGE_SENDTO_OK = OK + " Recipient ok"; private static final String MESSAGE_SENDTO_COMMAND_FIRST = ERROR + " " + COMMAND_SENDTO + " first"; private static final String MESSAGE_TITLE_MISSING = ERROR + " Title is missing"; private static final String MESSAGE_TITLE_OK = OK + " Title ok"; private static final String MESSAGE_TITLE_COMMAND_FIRST = ERROR + " " + COMMAND_TITLE + " first"; private static final String MESSAGE_CONTENT_MISSING = ERROR + " Content is missing"; private static final String MESSAGE_CONTENT_OK = OK + " Content ok"; private static final String MESSAGE_RECEIVE_EMPTY = ERROR + " Mailbox empty"; private static final String MESSAGE_RECEIVE_SAVE_ERROR = ERROR + " server error"; // property Socket client = null; BufferedReader inFromClient; BufferedWriter outToClient; private String username; private String password; private boolean auth = false; private String sendtoUsername; private String title; private String content; // constructer MailServerThread(Socket client) { this.client = client; try { inFromClient = new BufferedReader(new InputStreamReader(client.getInputStream())); outToClient = new BufferedWriter(new OutputStreamWriter(client.getOutputStream())); } catch (IOException e) { e.printStackTrace(); } } public void run() { try { // tmp buffers one input line from the client's socket. String tmp = inFromClient.readLine(); // The socket connection persists until the server receives a '#EXIT' while (tmp != null && !tmp.equals(COMMAND_EXIT)) { // find command int index = tmp.indexOf(" "); String str = index == -1 ? tmp : tmp.substring(0, index); // get command Command command = mapCommand.get(str); if (command == null) { str = MESSAGE_COMMAND_NOT_FOUND; } else { str = command.doIt(tmp); } outToClient.write(str + BR); outToClient.flush(); tmp = inFromClient.readLine(); } // #EXIT command outToClient.write(MESSAGE_EXIT); outToClient.flush(); } catch (IOException e) { System.out.println("ServerThread error:" + e.getMessage()); } finally { // close the client connection if (client != null && client.isConnected()) { try { client.close(); } catch (IOException e) { e.printStackTrace(); } } } } final Map<String, Command> mapCommand = new HashMap<String, Command>(); { mapCommand.put(COMMAND_USERNAME, new UsernameCommand()); mapCommand.put(COMMAND_PASSWORD, new PasswordCommand()); mapCommand.put(COMMAND_SENDTO, new SendToCommand()); mapCommand.put(COMMAND_TITLE, new TitleCommand()); mapCommand.put(COMMAND_CONTENT, new ContentCommand()); mapCommand.put(COMMAND_RECEIVE, new ReceiveCommand()); } interface Command { public String doIt(String str); } class UsernameCommand implements Command { public String doIt(String str) { password = null; auth = false; sendtoUsername = null; title = null; content = null; username = str.substring(COMMAND_USERNAME.length()).trim(); if (userMap.keySet().contains(username)) { password = null; auth = false; return MESSAGE_USERNAME_OK; } username = null; return MESSAGE_USERNAME_NOT_EXISTS; } } class PasswordCommand implements Command { public String doIt(String str) { if (username == null) { return MESSAGE_USERNAME_COMMAND_FIRST; } auth = false; sendtoUsername = null; title = null; content = null; password = str.substring(COMMAND_USERNAME.length()).trim(); String pass = userMap.get(username); if (pass != null && pass.equals(password)) { auth = true; return MESSAGE_USER_AUTH_OK; } else { password = null; auth = false; return MESSAGE_USER_AUTH_ERROR; } } } class SendToCommand implements Command { public String doIt(String str) { if (!auth) { return MESSAGE_AUTH_NEED; } title = null; content = null; sendtoUsername = str.substring(COMMAND_SENDTO.length()).trim(); if (sendtoUsername == null || sendtoUsername.length() == 0) { sendtoUsername = null; return MESSAGE_SENDTO_MISSION; } if (!userMap.keySet().contains(sendtoUsername)) { sendtoUsername = null; return MESSAGE_SENDTO_NOT_EXISTS; } return MESSAGE_SENDTO_OK; } } // #TITLE COMMAND class TitleCommand implements Command { public String doIt(String str) { if (!auth) { return MESSAGE_AUTH_NEED; } if (sendtoUsername == null) { return MESSAGE_SENDTO_COMMAND_FIRST; } content = null; title = str.substring(COMMAND_TITLE.length()).trim(); if (title == null || title.length() == 0) { return MESSAGE_TITLE_MISSING; } return MESSAGE_TITLE_OK; } } class ContentCommand implements Command { public String doIt(String str) { if (!auth) { return MESSAGE_AUTH_NEED; } if (title == null) { return MESSAGE_TITLE_COMMAND_FIRST; } content = str.substring(COMMAND_CONTENT.length()).trim(); if (content == null || content.length() == 0) { return MESSAGE_CONTENT_MISSING; } // save to file try { File file = new File(FILEPATH + sendtoUsername + FILENAME_EXT); if (!file.exists()) { file.createNewFile(); } FileWriter fw = new FileWriter(file, true); fw.write("FROM " + username + BR + BR); fw.write("TITLE " + title + BR + BR); fw.write("CONTENT " + content + BR + BR); fw.flush(); fw.close(); } catch (Exception ex) { ex.printStackTrace(); } return MESSAGE_CONTENT_OK; } } class ReceiveCommand implements Command { public String doIt(String str) { if (!auth) { return MESSAGE_AUTH_NEED; } StringBuilder builder = new StringBuilder(); try { File file = new File(FILEPATH + username + FILENAME_EXT); if (file.exists()) { BufferedReader reader = new BufferedReader(new FileReader(file)); String line = null; while ((line = reader.readLine()) != null) { builder.append(line); builder.append(BR); } reader.close(); // delete file; file.delete(); } else { builder.append(MESSAGE_RECEIVE_EMPTY); } } catch (Exception ex) { ex.printStackTrace(); builder.append(MESSAGE_RECEIVE_SAVE_ERROR); } return builder.toString(); } } static final Map<String, String> userMap = new HashMap<String, String>(); static { try { File file = new File(FILENAME_CLIENTINFO); BufferedReader bf = new BufferedReader(new FileReader(file)); String username; String password; while ((username = bf.readLine()) != null) { bf.readLine(); password = bf.readLine(); userMap.put(username, password); System.out.println(username + "/" + password); bf.readLine(); } } catch (Exception ex) { ex.printStackTrace(); // init error, force to exit System.exit(1); } }}

 

客户端：

import java.io.*;import java.net.*;/** * MailClient.<br> * connec to server, send message to sombody <br> * and(or) receive message of mine; */public class MailClient { public static void main(String[] args) throws IOException { Socket client = null; BufferedReader inFromServer, inFromUser; BufferedWriter outToServer; try { client = new Socket("127.0.0.1", 1234); // set the timeout of waiting for data of stream // 500 = 0.5s client.setSoTimeout(500); inFromServer = new BufferedReader(new InputStreamReader(client.getInputStream())); outToServer = new BufferedWriter(new OutputStreamWriter(client.getOutputStream())); inFromUser = new BufferedReader(new InputStreamReader(System.in)); // tmp buffers the input line from user's standard input. String tmp = inFromUser.readLine(); if (tmp == null) { return; } Receiver receiver = new Receiver(inFromServer); receiver.start(); // The client connection to the server persists until it gets a '#EXIT' // from the standard input. while (!tmp.equals("#EXIT")) { outToServer.write(tmp + "/r/n"); outToServer.flush(); tmp = inFromUser.readLine(); } // #EXIT command outToServer.write("#EXIT/r/n"); outToServer.flush(); // waiting for receiver thread end; try { receiver.join(); } catch (InterruptedException e) { e.printStackTrace(); } } catch (IOException e) { System.out.println("Cannot connect to server!"); System.exit(-1); } } /** * receive message from server. */ static class Receiver extends Thread { BufferedReader inFromServer; Receiver(BufferedReader inFromServer) { this.inFromServer = inFromServer; } public void run() { String line; while (true) { try { if ((line = inFromServer.readLine()) == null) { // no more data,return return; } System.out.println(line); } catch (SocketTimeoutException ex) { // when timeout, do nothing } catch (IOException e) { // when socket is close ,return return; } } } }}

 

 

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