go里面几个不同的字符串连接符的效率测试

Golang

在搞mysql的orm框架，在处理dsn时候，考虑字符串拼接。有很如下选择：

1. 直接用+
2. strings.Join
3. strings.Bandle
4. fmt.Sprintf

分别benchmark测试一下，直接上代码跑一下：

func dsnJson (Username string, Password string, Ip string, Port int64, Dbname string) string {
    dsn := strings.Join([]string{Username, ":", Password, "@tcp(", Ip, ":", strconv.FormatInt(Port, 10), ")/", Dbname, "?charset=utf8&timeout=5s&readTimeout=6s"}, "")
    return dsn
}
func dsnPlus (Username string, Password string, Ip string, Port int64, Dbname string) string {
    dsn := Username + ":" + Password + "@tcp(" + Ip + ":" + strconv.FormatInt(Port, 10) + ")/" + Dbname + "?charset=utf8&timeout=5s&readTimeout=6s"
    return dsn
}
func dsnSprintf (Username string, Password string, Ip string, Port int64, Dbname string) string {
    dsn := fmt.Sprintf("%s:%s@tcp(%s:%d)/%s?charset=utf8&timeout=5s&readTimeout=6s", Username, Password, Ip, Port, Dbname)
    return dsn
}
func dsnBuilder (Username string, Password string, Ip string, Port int64, Dbname string) string {
    var dsn2 strings.Builder
    dsn2.WriteString(Username)
    dsn2.WriteString(":")
    dsn2.WriteString(Password)
    dsn2.WriteString("@tcp(")
    dsn2.WriteString(Ip)
    dsn2.WriteString(":")
    dsn2.WriteString(strconv.FormatInt(Port, 10))
    dsn2.WriteString(")/")
    dsn2.WriteString(Dbname)
    dsn2.WriteString("?charset=utf8&timeout=5s&readTimeout=6s")
    dsn1 := dsn2.String()
    dsn2.Reset()
    return dsn1
}
func BenchmarkDsnJoin(b *testing.B) {
    for i := 0; i < b.N; i++ {
        _ = dsnJson("root", "123456", "127.0.0.1", 3306, "ApiDB")
    }
}
func BenchmarkDsnPlus(b *testing.B) {
    for i := 0; i < b.N; i++ {
        _ = dsnPlus("root", "123456", "127.0.0.1", 3306, "ApiDB")
    }
}
func BenchmarkDsnBuilder(b *testing.B) {
    for i := 0; i < b.N; i++ {
        _ = dsnBuilder("root", "123456", "127.0.0.1", 3306, "ApiDB")
    }
}
func BenchmarkDsnSprintf(b *testing.B) {
    for i := 0; i < b.N; i++ {
        _ = dsnSprintf("root", "123456", "127.0.0.1", 3306, "ApiDB")
    }
}

$ go test -bench=. -benchmem 
BenchmarkDsnJoin-12              8620420    138 ns/op     84 B/op   2 allocs/op
BenchmarkDsnPlus-12             10246611    115 ns/op     84 B/op   2 allocs/op
BenchmarkDsnBuilder-12           5990828    198 ns/op     256 B/op  6 allocs/op
BenchmarkDsnSprintf-12           3582942    337 ns/op     152 B/op  6 allocs/op
PASS
ok      command-line-arguments  6.388s

可以看出在少数量的字符拼接的情况下。Join和+的效率是最高的内存分配了2次，每次都是84byte，还是不错的。

所以，在确定字符串个数且很少的情况下，直接用+来拼接字符串吧，效率高又简单方便。