有條件的同學(xué)看一下官方，我這也是那抄的：https://golang.org/pkg/unicode/utf8/#ValidString

func Valid(p []byte) bool
Valid reports whether p consists entirely of valid UTF-8-encoded runes.

package main
import (
    "fmt"
    "unicode/utf8"
)
func main() {
    valid := []byte("Hello, 世界")
    invalid := []byte{0xff, 0xfe, 0xfd}
    fmt.Println(utf8.Valid(valid))
    fmt.Println(utf8.Valid(invalid))
}

func ValidRune(r rune) bool
ValidRune reports whether r can be legally encoded as UTF-8. Code points that are out of range or a surrogate half are illegal.

package main

import (
    "fmt"
    "unicode/utf8"
)

func main() {
    valid := 'a'
    invalid := rune(0xfffffff)

    fmt.Println(utf8.ValidRune(valid))
    fmt.Println(utf8.ValidRune(invalid))
}