8.1
下面展示一些 代码。

package main

import (
	"fmt"
	"net"
	"os"
	"time"
)

type Clock struct {
	Name   string
	Addr   string
｝
func main() {
	clocks := []Clock{
		{Name: "New York", Addr: "localhost:8000"},
		{Name: "London", Addr: "localhost:8001"},
		{Name: "Tokyo", Addr: "localhost:8002"},
	}

	fmt.Printf("%-15s %s\n", "Location", "Time")

	for _, clock := range clocks {
		conn, err := net.Dial("tcp", clock.Addr)
		if err != nil {
			fmt.Fprintf(os.Stderr, "Error connecting to %s: %v\n", clock.Name, err)
			continue
		}
		defer conn.Close()

		// 读取服务器发送的时间
		var timeStr string
		_, err = fmt.Fscan(conn, &timeStr)
		if err != nil {
			fmt.Fprintf(os.Stderr, "Error reading time from %s: %v\n", clock.Name, err)
			continue
		}

		// 解析时间
		t, err := time.Parse(time.RFC3339, timeStr)
		if err != nil {
			fmt.Fprintf(os.Stderr, "Error parsing time from %s: %v\n", clock.Name, err)
			continue
		}

		fmt.Printf("%-15s %s\n", clock.Name, t.Format(time.RFC3339))
	}
}

8.2
下面展示一些 代码。

package main

import (
	"bufio"
	"fmt"
	"net"
	"os"
	"strings"
)

func handleClient(conn net.Conn) {
	defer conn.Close()

	reader := bufio.NewReader(conn)
	writer := bufio.NewWriter(conn)

	for {
		// 读取客户端发送的命令
		cmd, err := reader.ReadString('\n')
		if err != nil {
			fmt.Println("Error reading command:", err)
			return
		}

		// 去除命令中的空白字符
		cmd = strings.TrimSpace(cmd)

		// 解析并处理命令
		switch cmd {
		case "cd":
			// 处理 cd 命令
			_, err := writer.WriteString("Change directory command executed.\n")
			if err != nil {
				fmt.Println("Error writing response:", err)
				return
			}
			writer.Flush()
		case "quit":
			// 处理退出命令
			return
		default:
			_, err := writer.WriteString("Unknown command.\n")
			if err != nil {
				fmt.Println("Error writing response:", err)
				return
			}
			writer.Flush()
		}
	}
}

func main() {
	listener, err := net.Listen("tcp", ":2121")
	if err != nil {
		fmt.Println("Error starting server:", err)
		return
	}

	defer listener.Close()

	fmt.Println("Server started, waiting for connections...")

	for {
		conn, err := listener.Accept()
		if err != nil {
			fmt.Println("Error accepting connection:", err)
			continue
		}

		go handleClient(conn)
	}
}