client.java

银行客户端应用模拟

import java.io.*;
import java.net.*;

public class Client{
	
	public static void main(String[] args) {
		boolean goon = true;
HERE:	while (goon) {
			System.out
					.println("Please give me the server name you want to login in: ");
			BufferedReader br = null;
			String hostName = null;
			String accountNumber = null;
			String clientAmount = null;
			Socket client = null;
			DataInputStream clientIn = null;
			DataOutputStream clientOut = null;
			
			// ask the client to input the name of the host
			br = new BufferedReader(new InputStreamReader(System.in));
			try {
				hostName = br.readLine();
			} catch (IOException e1) {
				e1.printStackTrace();
			}
			
			// connect to the host
			try {
				client = new Socket(hostName, 111);
			} catch (UnknownHostException e) {
				System.err.println("Host Unknown!");
				System.exit(1);
			} catch (IOException e) {
				System.err.println("Host Unknown!");
				System.exit(1);
			}
			
			try {
				clientIn = new DataInputStream(client.getInputStream());
				clientOut = new DataOutputStream(client.getOutputStream());
				clientOut.writeUTF("Hello!");
				clientOut.flush();

				System.out.println(clientIn.readUTF());
				
				// give the account number to the server
				br = new BufferedReader(new InputStreamReader(System.in));
				accountNumber = br.readLine();
				clientOut.writeUTF(accountNumber);
				clientOut.flush();
				
				// deal with login incorrect!!!
				if (clientIn.readBoolean()) {
					System.out
							.println("Login incorrect or time gap between two transaction is less than 1 minute!!!"
									+ "\nPlease try again!");
					continue HERE;
				}
				
				
				// when the time gap is too short, less than 1 minute
				if (clientIn.readBoolean()) {
					System.out
							.println("Login incorrect or time gap between two transaction is less than 1 minute!!!"
									+ "\nPlease try again!");
					continue HERE;
				}

				
				System.out.println(clientIn.readUTF());
				System.out.println(clientIn.readUTF());

				// give the server the amount of the money, deposite or withdraw
				br = new BufferedReader(new InputStreamReader(System.in));
				clientAmount = br.readLine();
				clientOut.writeUTF(clientAmount);
				clientOut.flush();
				System.out.println(clientIn.readUTF());

				System.out.println(clientIn.readUTF());

				// ask the client if he wants to make another transaction
				int again;
				br = new BufferedReader(new InputStreamReader(System.in));
				again = Integer.valueOf(br.readLine());
				clientOut.write(again);
				clientOut.flush();
				if (again == 1) {
					goon = true;
					continue HERE;			// loop again if he wants to make another transaction
				} else {
					goon = false;			// if not, terminate
					clientIn.close();
					clientOut.close();
					br.close();
					client.close();
				}
				
			} catch (IOException e) {
				System.err.println("Connection Lost, Please Try again!");
				System.exit(1);
			}
		}			
	}

}