1
type Reader interface {
2
  Read()
3
}
4

5
type Writer interface {
6
  Write()
7
}
8

9
type Book struct {
10
  Name string
11
}
12

13
func (b *Book) Read() {
14
  fmt.Println("read book:", b.Name)
15
}
16

17
func (b *Book) Write() {
18
  fmt.Println("write book:", b.Name)
19
}
20

21
func main() {
22
  book := &Book{Name: "Go 语言"} // 创建Book对象，name=Go 语言
23

24
  var r Reader // 多态：Reader r = book
25
  r = book
26

27
  var r1 Reader = book
28
  r1.Read()
29

30
  r.Read()
31

32
  var w Writer
33
  // r = pair<type:*Book, value:Book对象地址>
34
  w, ok := r.(Writer) // 检查 r 里面当前保存的真实类型，是否实现了 Writer 接口
35
  if ok {
36
    w.Write()
37
  } else {
38
    fmt.Println("Book is not have write method")
39
  }
40
}

1
type User struct {
2
  Name string
3
  Age  int
4
}
5

6
func (this *User) Call() {
7
  fmt.Println("User.Call()")
8
  fmt.Printf("%v\n", this)
9
}
10

11
func reflectNum(arg interface{}) {
12
  fmt.Println("reflectNum.type", reflect.TypeOf(arg))
13
  fmt.Println("reflectNum.value", reflect.ValueOf(arg))
14
}
15

16
func DoFileAndMethod(input interface{}) {
17
  // 获取input的type和value
18
  inputType := reflect.TypeOf(input)
19
  inputValue := reflect.ValueOf(input)
20
  inputKind := inputType.Kind()
21
  fmt.Println("input.type:", inputType)
22
  fmt.Println("input.value:", inputValue)
23
  fmt.Println("inputType.Kind():", inputKind)
24
  fmt.Println("reflect.Struct:", reflect.Struct)
25
  // 转成对应type,如User对象
26
  // 遍历input对象
27
  if inputType.Kind() != reflect.Struct {
28
    fmt.Println("input 不是结构体，不能遍历字段")
29
    return
30
  }
31
  for i := 0; i < inputType.NumField(); i++ {
32
    field := inputType.Field(i)
33
    value := inputValue.Field(i).Interface()
34

35
    fmt.Println("field.Name:", field.Name)
36
    fmt.Println("field.Value:", value)
37
  }
38
}
39

40
func main() {
41
  var num float64 = 23.4351
42
  reflectNum(num)
43

44
  var user = User{"zhangsan", 20}
45
  reflectNum(user)
46

47
  DoFileAndMethod(num)
48
}
49
--------------
50
reflectNum.type float64
51
reflectNum.value 23.4351
52
reflectNum.type main.User
53
reflectNum.value {zhangsan 20}
54
input.type: float64
55
input.value: 23.4351
56
inputType.Kind(): float64
57
reflect.Struct: struct
58
input 不是结构体，不能遍历字段

1
type Bank struct {
2
  Name string `json:"bank_name" desc:"名称"`
3
  Addr string `json:"bank_addr" desc:"地址"`
4
}
5

6
func findTag(str interface{}) {
7
  tag := reflect.TypeOf(str).Elem()
8
  for i := 0; i < tag.NumField(); i++ {
9
    desc := tag.Field(i).Tag.Get("desc")
10
    json := tag.Field(i).Tag.Get("json")
11
    fmt.Printf("desc:%s, json:%s\n", desc, json)
12
  }
13
}
14

15
func main() {
16
  spdb := Bank{"SPDB", "Shanghai"}
17
  fmt.Println(spdb)
18
  findTag(&spdb)
19
}
20
---------------
21
{SPDB Shanghai}
22
desc:名称, json:bank_name
23
desc:地址, json:bank_addr

1
type Movie struct {
2
  Title  string   `json:"title"`
3
  Year   int      `json:"year"`
4
  Price  float32  `json:"price"`
5
  Actors []string `json:"actors"`
6
}
7

8
func main() {
9
  movie := Movie{"喜剧之王", 2000, 190000, []string{"zhangsan", "lisi"}}
10
  jsonStr, err := json.Marshal(movie)
11
  if err != nil {
12
    fmt.Println("json.Marshal error", err)
13
    return
14
  }
15
  fmt.Printf("jsonStr = %s", jsonStr)
16
}
17
---------------------------
18
jsonStr= {"title":"喜剧之王","year":2000,"price":190000,"actors":["zhangsan","lisi"]}

1
type Movie struct {
2
  Title  string   `json:"title"`
3
  Year   int      `json:"year"`
4
  Price  float32  `json:"price"`
5
  Actors []string `json:"actors"`
6
}
7

8
func main() {
9
  movie := Movie{"喜剧之王", 2000, 190000, []string{"zhangsan", "lisi"}}
10
  fmt.Println(movie)
11
  jsonStr, err := json.Marshal(movie)
12
  if err != nil {
13
    fmt.Println("json.Marshal error", err)
14
    return
15
  }
16
  fmt.Printf("jsonStr = %s\n", jsonStr)
17

18
  // jsonStr转回结构体,赋值给myMovie
19
  myMovie := Movie{}
20
  err = json.Unmarshal(jsonStr, &myMovie)
21
  if err != nil {
22
    fmt.Println("json.Unmarshal error", err)
23
    return
24
  }
25
  fmt.Printf("myMovie = %v\n", myMovie)
26
}
27
------------------
28
{喜剧之王 2000 190000 [zhangsan lisi]}
29
jsonStr = {"title":"喜剧之王","year":2000,"price":190000,"actors":["zhangsan","lisi"]}
30
myMovie = {喜剧之王 2000 190000 [zhang