Network programming with Go

很不错的教程，讲的很详细。《Network programming with Go》http://jan.newmarch.name/golang/，照着教程写了一个小程序。  

//server.go
package main

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

func handleClient(conn *net.UDPConn){
    var buf [512]byte

    n, addr, err := conn.ReadFromUDP(buf[0:])
    if err != nil{
        return
    }
    fmt.Println(string(buf[0:]))
    daytime := time.Now().String()
    fmt.Println(n,addr)
    conn.WriteToUDP([]byte(daytime),addr)

}

func checkError(err error){
    if err != nil{
        fmt.Fprintf(os.Stderr,"Fatal error:%s",err.Error())
        os.Exit(1)
    }
}

func main(){
    service := ":1200"
    udpAddr, err := net.ResolveUDPAddr("up4",service)
    checkError(err)

    conn,err := net.ListenUDP("udp",udpAddr)
    checkError(err)

    for{
        handleClient(conn)
    }
}

//client.go
package main

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

func checkError(err error){
    if err != nil{
        fmt.Fprintf(os.Stderr,"Fatal error:%s",err.Error())
        os.Exit(1)
    }
}

func main(){
    if len(os.Args) != 2{
        fmt.Fprintf(os.Stderr, "Usage:%s host:port", os.Args[0])
        os.Exit(1)
    }
    service := os.Args[1]
    udpAddr, err := net.ResolveUDPAddr("up4",service)
    checkError(err)

    conn,err := net.DialUDP("udp",nil,udpAddr)
    checkError(err)

    _,err = conn.Write([]byte("hello"))
    checkError(err)

    var buf [512]byte
    n,err := conn.Read(buf[0:])
    checkError(err)
    fmt.Println(string(buf[0:n]))
    os.Exit(0)
}

,以后再扩展功能，先睡觉。