详解如何在Go语言中生成随机种子

import "time"

func TestSeedNanoTime(t *testing.T) {
	var seeds = make(map[int64]bool)
	for i := 0; i < 100000; i++ {
		seed := time.Now().UnixNano()
		seeds[seed] = true
		fmt.Println(seed)
	}
	fmt.Println(len(seeds))
}

import "hash/maphash"

func TestSeedMapHash(t *testing.T) {
	var seeds = make(map[int64]bool)
	for i := 0; i < 100000; i++ {
		seed := int64(new(maphash.Hash).Sum64())
		seeds[seed] = true
		fmt.Println(seed)
	}
	fmt.Println(len(seeds))
}

import (
	cryptoRand "crypto/rand"
	mathRand "math/rand"
)

func TestSeedCryptoRand(t *testing.T) {
	var seeds = make(map[int64]bool)
	for i := 0; i < 100000; i++ {
		var b [8]byte
		_, err := cryptoRand.Read(b[:])
		if err != nil {
			panic("cannot seed math/rand package with cryptographically secure random number generator")
		}
		seed := int64(binary.LittleEndian.Uint64(b[:]))
		seeds[seed] = true
		fmt.Println(seed)
	}
	fmt.Println(len(seeds))
}

func TestSeedRandomString(t *testing.T) {
	const alpha = "abcdefghijkmnpqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ23456789"
	size := 8
	var seeds = make(map[int64]bool)
	for i := 0; i < 100000; i++ {
		buf := make([]byte, size)
		for i := 0; i < size; i++ {
			buf[i] = alpha[mathRand.Intn(len(alpha))]
		}
		seed := int64(binary.LittleEndian.Uint64(buf[:]))
		seeds[seed] = true
		fmt.Println(seed)
	}
	fmt.Println(len(seeds))
}