Golang生成唯一的GUID

 

在uitl目錄下新建guid.go文件

package util

import (
    "crypto/md5"
    "crypto/rand"
    "encoding/binary"
    "encoding/hex"
    "fmt"
    "io"
    "os"
    "sync/atomic"
    "time" ) var objectIdCounter uint32 = 0 var machineId = readMachineId() type ObjectId string func readMachineId() []byte { var sum [3]byte id := sum[:] hostname, err1 := os.Hostname() if err1 != nil { _, err2 := io.ReadFull(rand.Reader, id) if err2 != nil { panic(fmt.Errorf("cannot get hostname: %v; %v", err1, err2)) } return id } hw := md5.New() hw.Write([]byte(hostname)) copy(id, hw.Sum(nil)) fmt.Println("readMachineId:" + string(id)) return id } // GUID returns a new unique ObjectId. // 4byte 時間， // 3byte 機器ID // 2byte pid // 3byte 自增ID func GetGUID() ObjectId { var b [12]byte // Timestamp, 4 bytes, big endian  binary.BigEndian.PutUint32(b[:], uint32(time.Now().Unix())) // Machine, first 3 bytes of md5(hostname) b[4] = machineId[0] b[5] = machineId[1] b[6] = machineId[2] // Pid, 2 bytes, specs don't specify endianness, but we use big endian. pid := os.Getpid() b[7] = byte(pid >> 8) b[8] = byte(pid) // Increment, 3 bytes, big endian i := atomic.AddUint32(&objectIdCounter, 1) b[9] = byte(i >> 16) b[10] = byte(i >> 8) b[11] = byte(i) return ObjectId(b[:]) } // Hex returns a hex representation of the ObjectId. // 返回16進制對應的字符串 func (id ObjectId) Hex() string { return hex.EncodeToString([]byte(id)) }

調用方法

strGuid := GetGUID().Hex(). //5f23d8c5dc1d1c5e33000001