go模拟网络数据包传送代码

1.构建数据包过程

package protocol

import (
    "bufio"
    "bytes"
    "encoding/binary"
    "fmt"
)

//构建网络中数据包格式
func Encode (message string ) []byte {
    var length = int32(len(message))
    var pkg = new(bytes.Buffer)
    err:=binary.Write(pkg,binary.LittleEndian,length)//前四个字节
    if err != nil {
        fmt.Println("build pkg is error")
        return nil
    }
    err=binary.Write(pkg,binary.LittleEndian,[]byte(message))
    if err != nil {
        return nil
    }
    return pkg.Bytes()
}
//解包过程
func Decode( reader *bufio.Reader) string {
    lengthBytes,_:= reader.Peek(4)//前4个字节数据
    lengthBuff:=bytes.NewBuffer(lengthBytes)
    var length int32
    binary.Read(lengthBuff,binary.LittleEndian,&length)

    //if int32(reader.Buffered()) < length +4 {
    //    return nil
    //}

    pack:=make([]byte, int(4+length))
    reader.Read(pack)
    return string(pack[4:])

}

1.服务端

package main

import (
    "bufio"
    "fmt"
    "net"
    "protocol"
)

func process(conn net.Conn){
    defer conn.Close()
    reader:=bufio.NewReader(conn)
    for {
        msg:= protocol.Decode(reader)
        fmt.Printf("%v\n",msg)
    }
}

func main(){
    listener,err:=net.Listen("tcp","127.0.0.1:8890")
    if err != nil {
        fmt.Println("start server is erros")
        return
    }
    for {
        conn,_:= listener.Accept()
        go process(conn)
    }
    defer listener.Close()
}

2.客户端

package main

import (
    "log"
    "net"
    "protocol"
    "time"
)

func main(){
    conn,err:=net.Dial("tcp","127.0.0.1:8890")
    if err != nil {
        log.Fatal("is error")
        return
    }
    str:="hello word你好"
    for i:=0;i<10;i++ {
        bytes:= protocol.Encode(str)
        conn.Write(bytes)
        time.Sleep(time.Second)
    }
}