初学网络编程 今天的网络编程作业

1. 使用基于TCP的Java Socket编程，完成如下功能：

1) 要求从客户端录入几个字符，发送到服务器端。

2) 由服务器端将接收到的字符进行输出。

3) 服务器端向客户端发出“您的信息已收到”作为响应。

4) 客户端接收服务器端的响应信息。

public class Client {
	public static void main(String[] args) {
		System.out.println("-----------客户端-----------");
		try {
			Socket s = new Socket("127.0.0.1", 8888);
			OutputStream os = s.getOutputStream();
			InputStream is = s.getInputStream();
			OutputStreamWriter osw = new OutputStreamWriter(os);
			InputStreamReader isr = new InputStreamReader(is);
			String ss = "你好，我是客户端";
			osw.write(ss);
			osw.flush();
			char[] c = new char[1024];
			int len = isr.read(c);
			String se = new String(c, 0, len);
			System.out.println("服务器端说:" + se);
			osw.close();
			isr.close();
			os.close();
			is.close();
			s.close();
		} catch (UnknownHostException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
}

public class Server {
	public static void main(String[] args) {
		System.out.println("-------------服务器端-------------");
		try {
			ServerSocket ss = new ServerSocket(8888);
			Socket a = ss.accept();
			OutputStream os = a.getOutputStream();
			InputStream is = a.getInputStream();
			InputStreamReader isr = new InputStreamReader(is);
			char[] c = new char[1024];
			int len = isr.read(c);
			String se = new String(c, 0, len);
			System.out.println("客户端说:" + se);
			OutputStreamWriter osw = new OutputStreamWriter(os);
			String sc = "服务器端收到了";
			osw.write(sc);
			osw.flush();
			isr.close();
			osw.close();
			is.close();
			os.close();
			ss.close();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
}

1. 使用TCP网络编程完成用户登录功能：客户端输入用户名和密码，向服务器发出登录请求；服务器接收数据并进行判断，如果用户名和密码均是bjsxt，则登录成功，否则登录失败，返回相应响应信息；客户端接收响应信息并输出登录结果。

1) 用户User类已提供构造方法 public User(String username,String password)。

2) 客户端采用ObjectOutputStream发送封装了用户名和密码的User对象。

public class User implements Serializable {
	String username;
	String password;

	public User(String username, String password) {
		this.username = username;
		this.password = password;
	}

	public String getUsername() {
		return username;
	}

	public void setUsername(String username) {
		this.username = username;
	}

	public String getPassword() {
		return password;
	}

	public void setPassword(String password) {
		this.password = password;
	}

}

public class LoginClient {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		System.out.println("请输入用户名:");
		String username = sc.nextLine();
		System.out.println("请输入密码:");
		String password = sc.nextLine();
		User u = new User(username, password);
		try {
			Socket s = new Socket("127.0.0.1", 8888);
			OutputStream os = s.getOutputStream();
			ObjectOutputStream oos = new ObjectOutputStream(os);
			oos.writeObject(u);
			oos.flush();
			InputStream is = s.getInputStream();
			DataInputStream dis = new DataInputStream(is);
			String utf = dis.readUTF();
			System.out.println(utf);
			dis.close();
			is.close();
			oos.close();
			os.close();
			s.close();
		} catch (UnknownHostException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
}

public class LoginServer {
	static Map map = new HashMap();
	static {
		map.put("bjsxt", "bjsxt");
		map.put("zzsxt", "zzsxt");
		map.put("shsxt", "shsxt");
		map.put("whsxt", "whsxt");
	}
	static int num = 0;

	public static void main(String[] args) {
		ServerSocket ss = null;
		Socket s = null;
		ObjectInputStream ois = null;
		DataOutputStream dos = null;
		try {
			ss = new ServerSocket(8888);
			while (true) {
				s = ss.accept();
				InputStream is = s.getInputStream();
				ois = new ObjectInputStream(is);
				User u = (User) ois.readObject();
				String username = u.getUsername();
				String password = u.getPassword();
				String m = map.get(username);
				String str;
				if (m != null && m.equals(password)) {
					num++;
					str = "恭喜你,登陆成功!您是第" + num + "位访客";
				} else {
					str = "用户名密码错误";
				}
				OutputStream os = s.getOutputStream();
				dos = new DataOutputStream(os);
				dos.writeUTF(str);
				dos.flush();
			}
		} catch (IOException e) {
			e.printStackTrace();
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		} finally {
			try {
				s.close();
				dos.close();
				ois.close();
				ss.close();
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
	}
}