1 package main
 2 
 3 import (
 4     "awesomeProject/retriever/mock"
 5     "awesomeProject/retriever/real"
 6     "fmt"
 7     "time"
 8 )
 9 
10 //接口由使用者定义
11 //接口的实现是隐式的，只要实现接口里的方法
12 //接口变量自带指针
13 //接口变量采用值传递，几乎不需要使用接口的指针
14 //指针接收者实现只能以指针方式使用，值接收者都可
15 //查看接口变量:
16 //             表示任何类型 :interface{}
17 //             Type Assertion
18 //             Type Switch
19 
20 type Retriever interface {
21      Get( url string) string
22 }
23 
24 type Postser interface {
25     Post(url string,
26         form map[string] string) string
27 }
28 
29 const  url  = "http://www.baidu.com"
30 func post( postser Postser)  {
31     postser.Post(url, map[string] string{
32             "name": "yuxiaoba",
33             "course": "go",
34         })
35 }
36 
37 type RetrieverPoster interface {  //接口的组合
38     Retriever
39     Postser
40 }
41 
42 func session( s RetrieverPoster)  string{
43 
44     s.Post(url, map[string]string{
45         "contents": "another faked baidu.com",
46     })
47     return s.Get(url)
48 }
49 //func download( r Retriever) string {
50 //    return  r.Get("http://www.baidu.com")
51 //}
52 
53 func inspect(r Retriever)  {
54     switch v := r.(type) {
55     case *mock.Retriever:
56         fmt.Println("Contents", v.Contents)
57 
58     case *real.Retriever:
59         fmt.Println("UserAgent", v.UserAgent)
60     }
61     fmt.Printf("%T %v
", r, r)
62     fmt.Println()
63 }
64 
65 func main() {
66     var r  Retriever
67     retriever := mock.Retriever{"this is a fake baidu"}
68     r = &retriever
69     inspect(r)  //Contents this is a fake baidu
70                 //     *mock.Retriever Retriver: {Contents = this is a fake baidu}
71 
72     r = &real.Retriever{
73         UserAgent: "Mozilla/5.0",
74         TimeOut: time.Minute,
75     }
76     inspect(r)     //UserAgent Mozilla/5.0
77                   /*   *real.Retriever &{Mozilla/5.0 1m0s}*/
78 
79     //type assertion
80     realRetriever := r.(*real.Retriever)
81 
82     if mockRetriever , ok := r.(*mock.Retriever); ok {
83         fmt.Println(mockRetriever.Contents)
84     }else {
85         fmt.Println("not mock retriever")   //not mock retriever
86     }
87 
88     fmt.Println(realRetriever.TimeOut)  //1m0s
89     /*    fmt.Println(download(r))*/
90 
91     fmt.Println(session(&retriever))  //another faked baidu.com
92 
93 }

package real

import (
    "time"
    "net/http"
    "net/http/httputil"
)

//真实retriever
type Retriever struct {
    UserAgent string
    TimeOut time.Duration
}

func (r *Retriever) Get(url string) string {    //指针接收者
    resp, err := http.Get(url)
    if err != nil {
        panic(err)
    }
    result, err := httputil.DumpResponse( resp, true)
    resp.Body.Close()

    if err != nil{
        panic(err)
    }
    return  string(result)
}

 1 package mock
 2 
 3 import "fmt"
 4 
 5 type  Retriever struct {
 6     Contents string
 7 }
 8 
 9 func (r *Retriever) String() string {
10     return fmt.Sprintf(
11         "Retriver: {Contents = %s}", r.Contents,
12     )
13 }
14 
15 func (r *Retriever) Post (url string,
16     form map[string]string) string {
17     r.Contents = form["contents"]
18     return  "OK"
19 }
20 
21 func (r *Retriever) Get(url string) string  {
22     return r.Contents
23 }