Golang的反射由reflect包提供支持，有两个重要类型：一个Type表示一个Go类型，它是一个接口。一个Value可以持有任意类型的值。
import ( "fmt" "reflect" "strconv" ) func Display(name string, x interface{}) { fmt.Printf("Display %s (%T):\n", name, x) display(name, reflect.ValueOf(x)) } func formatAtom(v reflect.Value) string { switch v.Kind() { case reflect.Invalid: return "invalid" case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64: return strconv.FormatInt(v.Int(), 10) case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64: return strconv.FormatUint(v.Uint(), 10) case reflect.Bool: return strconv.FormatBool(v.Bool()) case reflect.String: return strconv.Quote(v.String()) case reflect.Chan, reflect.Func, reflect.Ptr, reflect.Slice, reflect.Map: return v.Type().String() + "0x" + strconv.FormatUint(uint64(v.Pointer()), 16) default: return v.Type().String() + "value" } } func display(path string, v reflect.Value) { switch v.Kind() { case reflect.Invalid: fmt.Printf("%s = invalid\n", path) case reflect.Slice, reflect.Array: for i := 0; i < v.Len(); i++ { display(fmt.Sprintf("%s[%d]", path, i), v.Index(i)) } case reflect.Struct: for i := 0; i < v.NumField(); i++ { fieldPath := fmt.Sprintf("%s.%s", path, v.Type().Field(i).Name) display(fieldPath, v.Field(i)) } case reflect.Map: for _, key := range v.MapKeys(){ display(fmt.Sprintf("%s[%s]", path, formatAtom(key)), v.MapIndex(key)) } case reflect.Ptr: if v.IsNil() { fmt.Printf("%s = nil\n", path) } else { display(fmt.Sprintf("*%s", path), v.Elem()) } case reflect.Interface: if v.IsNil() { fmt.Printf("%s = nil\n", path) } else { fmt.Printf("%s.type = %s\n", path, v.Elem().Type()) display(path+".value", v.Elem()) } default: fmt.Printf("%s = %s\n", path, formatAtom(v)) } } import "testing" type Movie struct { Title, Subtitle string Year int Color bool Actor map[string]string Oscars []string Sequel *string } var strangelove = Movie{ Title: "Dr. Strangelove", Subtitle: "How I Learned to Stop Worrying and Love the Bomb", Year: 1964, Color: false, Actor: map[string]string{ "Dr. Strangelove": "Peter Sellers", "Grp. Cat. Lionel Mandrake": "Peter Sellers", "Gen. Buck Turgidson": "George Hayden", }, Oscars: []string{ "Best Actor (Nomin.)", "Best Adapted Screeenplay (Nomin.)", }, } func TestDisplay(t *testing.T) { Display("strangelove",strangelove) }Display strangelove (main.Movie): strangelove.Title = “Dr. Strangelove” strangelove.Subtitle = “How I Learned to Stop Worrying and Love the Bomb” strangelove.Year = 1964 strangelove.Color = false strangelove.Actor[“Dr. Strangelove”] = “Peter Sellers” strangelove.Actor[“Grp. Cat. Lionel Mandrake”] = “Peter Sellers” strangelove.Actor[“Gen. Buck Turgidson”] = “George Hayden” strangelove.Oscars[0] = “Best Actor (Nomin.)” strangelove.Oscars[1] = “Best Adapted Screeenplay (Nomin.)” strangelove.Sequel = nil
