Question

编写一个客户端应用程序，在它打印新值之后将机器时间设置为给定主机约会该应用程序使用TCP端口37中可用的主机服务的标准日期。参数是主机名和端口号。端口号的默认值是37.如果是程序运行时没有参数，它与localhost通信。程序使用标准输出到打印信息。重要的提示： dateAtHost服务给出一个带符号的32位整数，其自1月1日起的秒数， 1990年。 DateAtHost服务器编写一个侦听给定TCP端口的服务器应用程序，它以32位整数发送日期格式化到客户端，如主机服务的标准日期。程序参数是端口号。端口号的默认值为37.程序使用标准输出来打印信息。

DateAthostclient.java

package DateAthostclient;
import java.net.*;
import java.io.*;
import java.util.*;
public class DateAthostclient {
   static final int defaultPort = 37;
   static final long offset = 2208988800L;

 public static void main(String[] args) {
    // TODO code application logic here
    int portNumber;
    Socket clientSocket;
    DataInputStream timeStream;
    String hostName;
    switch(args.length) {
    case 1: hostName = args[0];
    portNumber = defaultPort;//dateAtHost Port;
    break;
    case 2: hostName = args[0];
    portNumber = new Integer(args[1]).intValue();
    break;
    default:
    hostName = "localhost";
    portNumber = defaultPort;//dateAtHost Port;
   }

   try {
   clientSocket = new Socket(hostName,portNumber);
   timeStream = new DataInputStream(clientSocket.getInputStream());
   int dateAtHost = timeStream.readInt() + (int)(1L<<32);
   new Date().setTime((dateAtHost-offset)*1000);
   System.out.println("It is " + new Date().toString() + " at " +hostName);
   timeStream.close();
    clientSocket.close();
   }
   catch (UnknownHostException {
   System.err.println(" Unknown host error");
   }
   catch (ConnectException e) {
   System.out.println(" Service unavailable on port "+portNumber+"of host       "+hostName);
   }
  catch (IOException e) {
  System.err.println(" Communication error occured\r\n "+e);
  }
  }

 }


dayAtHostserver.java
package dayAtHostserver;
import java.net.*;
import java.io.*;
import java.util.*;
 public class dayAtHostserver {
 public final static int daytimePort = 13;


public static void main(String[] args) {
    // TODO code application logic here
    ServerSocket theServerSocket;
    Socket theConnectionSocket;
    PrintWriter out;
    try {
    theServerSocket = new ServerSocket(daytimePort);
    System.out.println("Timeserver ready at port "+daytimePort);
    try {
    while (true) {
    theConnectionSocket = theServerSocket.accept();
    System.out.println("Request arrived!");
    out = new PrintWriter(theConnectionSocket.getOutputStream(),true);
    out.println(new Date());
    theConnectionSocket.close();
    }
    }
    catch (IOException e) {
    theServerSocket.close();
    System.err.println(e);
     }
     }
    catch (IOException e) {
    System.err.println(e);

    }
    }
    }

    我有两个问题     1）我需要了解什么是（1L＆lt; 32）以及为什么他在这里使用它？     2）当我运行服务器并且客户端日期未在客户端
中收到时

命令行DateAthost客户端

0 个答案: