"Go learning note" 13, reflective reflect

This is a creation in Article, where the information may have evolved or changed.

Reflective Reflection

Reflection can greatly increase the flexibility of the program, so that interface{} has a greater scope of play
Reflection uses the TypeOf and valueof functions to get target object information from the interface
Reflection will use anonymous fields as separate fields (anonymous field nature)
You want to use reflection to modify the state of an object, if Interface.data is settable, which is pointer-interface
Methods can be called dynamically by reflection

Structural Body Reflection

12345678910111213141516171819202122232425262728293031323334353637383940

typeUserstruct{IdintNamestringAgeint} func (u User) Hello() {FMT. Println ("Hello World")} func Info(o interface{}) {t: = reflect. TypeOf (o)ifK: = T.kind (); K! = reflect. Struct {fmt. Println ("XXX")return}fmt. Println ("Type:", T.name ()) V: = reflect. ValueOf (o) fmt. Println ("Fields:") forI: =0; I < T.numfield (); i++ {f: = T.field (i) Val: = V.field (i). Interface () fmt. Printf ("%6s:%v =%v \ n", F.name, F.type, Val)} forI: =0; I < T.nummethod (); i++ {m: = T.method (i) fmt. Printf ("%6s:%v\n", M.name, M.type)}} func main() {u: = user{1,"OK", A}info (U)}

Calling Anonymous fields through reflection

1234567891011121314151617

type User struct {Id int Name string age int } type Manager struct {usertitle string } func main () {m: = Manager{user:user{1 , "OK" , 19 }, Title: }t: = reflect. TypeOf (m) fmt. Printf ( "% #v \ n" , T.fieldbyindex ([]int { 0 , 0 })}

Modifying an object's state by reflection

Basic type

123456

func Main ()t: = reflect. ValueOf (&x) T.elem (). Setint (111) fmt. PRINTLN (x)}

Structural body

123456789101112131415161718192021222324252627282930313233

func main() {u: = user{1,"OK", +}set (&u) fmt. PRINTLN (U)}typeUserstruct{IdintNamestringAgeint} func Set(o interface{}) {V: = reflect. ValueOf (o)ifV.kind () = = reflect. Ptr &&!v.elem (). Canset () {fmt. Println ("xxxx")return}Else{v = V.elem ()}f: = V.fieldbyname ("Name")if!f.isvalid () {fmt. Println ("Bad")return}ifF.kind () = = reflect. String {f.setstring ("Success")}}

Dynamic Call method by reflection

12345678910111213141516171819

type User struct {Id int Name string age int } func (U User) hello string ) {FMT. Println ( "Hello" , name, , u.name)}func main () {u: = User{1 , , 19 } V: = reflect. ValueOf (u) MV: = V.methodbyname ( "Hello" ) args: = []reflect. Value{reflect. ValueOf ( "hundred" )}mv. Call (args)}