Using JSON in Golang

Some examples of using JSON in Golang

Go_json_test Project Main.gopackage mainimport ("Encoding/json" "FMT") func encode_from_map_test () {fmt. Printf ("encode_from_map_test\n") m: = map[string][]string{"level": {"Debug"}, "message": {"File not fo und "," Stack Overflow "},} if data, err: = json. Marshal (m); Err = = Nil {fmt. Printf ("%s\n", data)}}type gameinfo struct {game_id int64 game_map string game_time int32}func Encode_fro M_object_test () {fmt. Printf ("encode_from_object_test\n") Game_infos: = []gameinfo{gameinfo{1, "Map1", +}, gameinfo{2, "MAP2" , $},} if data, err: = json. Marshal (Game_infos); Err = = Nil {fmt.    Printf ("%s\n", data)}}type GameInfo1 struct {game_id int64 ' JSON: "game_id" '//game_id resolves to game_id  Game_map string ' JSON: ' game_map,omitempty '///gamemap resolves to game_map, ignoring empty game_time int32 game_name string ' json: '-' ' Ignore Game_name}func encode_from_object_tag_test () {fmt. Printf ("Encode_frOm_object_tag_test\n ") Game_infos: = []gameinfo1{gameinfo1{1," Map1 "," name1 "}, Gameinfo1{2," Map2 ", "Name2"}, Gameinfo1{3, "", "Name3"},} if data, err: = json. Marshal (Game_infos); Err = = Nil {fmt. Printf ("%s\n", data)}}type baseobject struct {field_a string field_b string}type deriveobject struct {baseo Bject Field_c String}func Encode_from_object_with_anonymous_field () {fmt. Printf ("encode_from_object_with_anonymous_field\n") object: = deriveobject{baseobject{"A", "B"}, "C"} if data, err: = json. Marshal (object); Err = = Nil {fmt. Printf ("%s\n", data)}}//convert interface//when calling Marshal (v interface{}), the function will determine whether v satisfies the JSON. Marshaler or encoding. Marshaler interface,//If satisfied, the two interfaces are called for conversion (if two are satisfied, the JSON is called first. Marshaler)/*//JSON. Marshalertype Marshaler Interface {Marshaljson () ([]byte, error)}//encoding.    Textmarshalertype Textmarshaler Interface {marshaltext () (text []byte, err Error)}*/type point struct {X int Y Int}func (pt Point) Marshaljson ([]byte, error) {return []byte (FMT). Sprintf (' {' px ':%d, ' py ':%d} ', Pt. X, Pt. Y)), Nil}func Encode_from_object_with_marshaler_interface () {fmt. Printf ("encode_from_object_with_marshaler_interface\n") if data, err: = json. Marshal (POINT{50, 50}); Err = = Nil {fmt. Printf ("%s\n", data)} else {fmt. Printf ("Error%s\n", err.) Error ())}}type Point1 struct {X int Y int}func (pt Point1) Marshaltext () ([]byte, error) {return []byte (FMT . Sprintf (' {' px ':%d, ' py ':%d} ', Pt. X, Pt. Y)), Nil}func Encode_from_object_with_text_marshaler_interface () {fmt. Printf ("encode_from_object_with_text_marshaler_interface\n") if data, err: = json. Marshal (POINT1{50, 50}); Err = = Nil {fmt. Printf ("%s\n", data)} else {fmt. Printf ("Error%s\n", err.) Error ())}}//decode TestFunc decode_to_map_test () {fmt. Printf ("decode_to_map_test\n") Data: = ' [{' Level ': ' Debug ', ' MSG ': ' File: \ ' test.txt\ ' not Found '}, '+ ' {"Level": "", "MSG": "Logic Error"}] ' var Debug_infos []map[string]string JSON. Unmarshal ([]byte (data), &debug_infos) fmt. Println (Debug_infos)}type debuginfo struct {level string MSG string Author string//non-exported field is not parsed by JSON}func (db Ginfo debuginfo) string () string {return FMT. Sprintf ("{level:%s, MSG:%s}", Dbginfo.level, dbginfo.msg)}func decode_to_object_test () {fmt. Printf ("decode_to_object_test\n") Data: = ' [{"Level]:" Debug "," MSG ":" File not Found "," Author ":" Cynhard "}, ' + ' {" L Evel ":" "," MSG ":" Logic Error "," Author ":" Gopher "}] ' var Dbginfos []debuginfo JSON. Unmarshal ([]byte (data), &dbginfos) fmt. Println (Dbginfos)}type debuginfotag struct {level string ' JSON: ' Level '//level decoded to level MSG string ' JSON: '    Message "//message decoded to MSG Author string ' JSON:"-"'///Ignore Author}func (Dbginfo Debuginfotag) string () string { Return to FMT. Sprintf ("{level:%s, MSG:%s}", Dbginfo.level, dbginfo.msg)}func Decode_to_objeCt_tag_test () {fmt.        Printf ("decode_to_object_tag_test\n") Data: = ' [{' Level ': ' Debug ', ' Message ': ' File not Found ', ' Author ': ' Cynhard '}, ' + ' {' Level ': ', ' message ': ' Logic error ', ' Author ': ' Gopher '}] ' var Dbginfos []debuginfotag JSON. Unmarshal ([]byte (data), &dbginfos) fmt. Println (Dbginfos)}type pointx struct{X, Y int}type Circle struct {pointx Radius int}func (c Circle) String () stri ng {return FMT. Sprintf ("{point{x:%d, Y:%d}, Radius:%d}", c.pointx.x, C.pointx.y, C.radius)}func decode_to_object_with_anonymous _field () {fmt. Printf ("decode_to_object_with_anonymous_field\n") Data: = ' {' X ': +, ' Y ': $, ' Radius ': +} ' var c Circle json. Unmarshal ([]byte (data), &c) fmt. Println (c)}//decode convert interface//decoding when the JSON is satisfied according to the parameters. Unmarshaler and Encoding.textunmarshaler call the corresponding function (if two functions are present, priority call Unmarshaljson)/*//JSON. Unmarshalertype Unmarshaler Interface {Unmarshaljson ([]byte) error}//encoding.    Textunmarshalertype Textunmarshaler Interface {Unmarshaltext (text []byte) error}*/type pointy struct{X, Y int}func (PT pointy) Marshaljson () ([]byte, error) {//No Decode, just print return []byte (FMT. Sprintf (' {' X ':%d, ' Y ':%d} ', Pt. X, Pt. Y)), Nil}func Decode_to_object_with_marshaler_interface () {fmt. Printf ("decode_to_object_with_marshaler_interface\n") if data, err: = json. Marshal (POINTY{50, 50}); Err = = Nil {fmt. Printf ("%s\n", data)}}func main () {FMT.    Println ("JSON test!") Fmt. Printf ("Ecode test\n") encode_from_map_test () encode_from_object_test () encode_from_object_tag_test () Encode_f Rom_object_with_anonymous_field () encode_from_object_with_marshaler_interface () Encode_from_object_with_text_ Marshaler_interface () fmt. Printf ("Decode test\n") decode_to_map_test () decode_to_object_test () decode_to_object_tag_test () decode_to_obj Ect_with_anonymous_field () Decode_to_object_with_marshaler_interface ()}

Run Result:

JSON Test!ecode testencode_from_map_test{"level": ["Debug"], "message": ["File not Found", "Stack Overflow"]}encode_ from_object_test[{"game_id": 1, "Game_map": "Map1", "Game_time": 20},{"game_id": 2, "Game_map": "Map2", "Game_time": 60} ]encode_from_object_tag_test[{"game_id": 1, "Game_map": "Map1", "Game_time": 20},{"game_id": 2, "Game_map": "Map2", " Game_time ": 60},{" game_id ": 3," Game_time ": 120}]encode_from_object_with_anonymous_field{" Field_a ":" A "," Field_b ":" B "," Field_c ":" C "}encode_from_object_with_marshaler_interface{" px ":" py ": 50}encode_from_object_with_text_ Marshaler_interface "{\" px\ ":", \ "py\": "Decode Testdecode_to_map_test[map[level:debug msg:file:" Test.txt "not Found] Map[level:msg:logic error]]decode_to_object_test[{level:debug, msg:file not Found} {level:, Msg:logic error}]d Ecode_to_object_tag_test[{level:debug, Msg:file not Found} {level:, Msg:logic error}]decode_to_object_with_anonymous _FIELD{POINT{X:80, y:80}, radius:40}decode_to_object_with_marshaler_interface{"X": +, "Y": 50}