02、client端开发

package main
import (
    "bufio"
    "fmt"
    "io"
    "net"
    "os"
    "strconv"
    "strings"
)
//写函数和读函数同server端，要保持一致
func write(conn net.Conn, txt string) error {
    length := len(txt)
    _, err := conn.Write([]byte(fmt.Sprintf("%05d", length)))
    if err != nil {
        fmt.Println(err)
        return err
    }
    _, err = conn.Write([]byte(txt))
    if err != nil {
        fmt.Println(err)
        return err
    }
    return nil
}
//写函数和读函数同server端，要保持一致
func read(conn net.Conn) (string, error) {
    lengthBytes := make([]byte, 5)
    _, err := conn.Read(lengthBytes)
    if err != nil {
        fmt.Println(err)
        return "", err
    }
    length, err := strconv.Atoi(string(lengthBytes))
    if err != nil {
        fmt.Println(err)
        return "", err
    }
    ctx := make([]byte, length)
    _, err = conn.Read(ctx)
    if err != nil {
        fmt.Println(err)
        return "", err
    }
    return string(ctx), nil
}
func input(prompt string) string {
    fmt.Print(prompt)
    scanner := bufio.NewScanner(os.Stdin)
    scanner.Scan()
    return strings.TrimSpace(scanner.Text())
}
func main() {
    addr := "127.0.0.1:8888"
    protocol := "tcp"
    // 1. 创建连接
    conn, err := net.Dial(protocol, addr)
    if err != nil {
        fmt.Println(err)
        return
    }
    // 2. 交换数据
    for {
        txt := input("请输入信息:")
        if txt == "exit" {
            break
        }
        err := write(conn, txt)
        if err != nil {
            if err != io.EOF {
                fmt.Println(err)
            }
            break
        }
        txt, err = read(conn)
        if err != nil {
            if err != io.EOF {
                fmt.Println(err)
            }
            break
        }
        fmt.Printf("服务器端响应: %s\n", txt)
    }
    // conn.Read()
    // 3. 关闭
    conn.Close()
}