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| // Movie prints Movies as JSON.
// See page 108.
// 程序负责收集各种电影评论并提供反馈功
var movies = []Movie{
{Title: "Casablanca", Year: 1942, Color: false,
Actors: []string{"Humphrey Bogart", "Ingrid Bergman"}},
{Title: "Cool Hand Luke", Year: 1967, Color: true,
Actors: []string{"Paul Newman"}},
{Title: "Bullitt", Year: 1968, Color: true,
Actors: []string{"Steve McQueen", "Jacqueline Bisset"}},
// ...
}
func main() {
{
data, err := json.Marshal(movies)
if err != nil {
log.Fatalf("JSON marshaling failed: %s", err)
}
fmt.Printf("%s\n", data)
}
{
// 格式化json输出，产生整齐缩进的输出
// MarshalIndent()有两个额外的字符串参数，用于表示每一行输出的前缀和每一个层级的缩进：
// 译注：在最后一个成员或元素后面并没有逗号分隔符
data, err := json.MarshalIndent(movies, "", " ")
if err != nil {
log.Fatalf("JSON marshaling failed: %s", err)
}
fmt.Printf("%s\n", data)
// 代码将JSON格式的电影数据data解码为一个结构体slice，结构体中只有Title成员
var titles []struct{ Title string }
// 通过定义合适的Go语言数据结构，我们可以选择性地解码JSON中感兴趣的成员
if err := json.Unmarshal(data, &titles); err != nil {
log.Fatalf("JSON unmarshaling failed: %s", err)
}
// 这里的slice将被只含有Title信息的值填充，其它JSON成员将被忽略
fmt.Println(titles) // [{Casablanca} {Cool Hand Luke} {Bullitt}]
}
}
/*
//!+output
[{"Title":"Casablanca","released":1942,"Actors":["Humphrey Bogart","Ingr
id Bergman"]},{"Title":"Cool Hand Luke","released":1967,"color":true,"Ac
tors":["Paul Newman"]},{"Title":"Bullitt","released":1968,"color":true,"
Actors":["Steve McQueen","Jacqueline Bisset"]}]
//!-output
*/
/*
//!+indented
[
{
"Title": "Casablanca",
"released": 1942,
"Actors": [
"Humphrey Bogart",
"Ingrid Bergman"
]
},
{
"Title": "Cool Hand Luke",
"released": 1967,
"color": true,
"Actors": [
"Paul Newman"
]
},
{
"Title": "Bullitt",
"released": 1968,
"color": true,
"Actors": [
"Steve McQueen",
"Jacqueline Bisset"
]
}
]
//!-indented
*/
|