[英]Golang modify json without struct
type Struct struct {
Value string `json:"value"`
Value1 string `json:"value_one"`
Nest Nested `json:"nest"`
}
type Nested struct {
Something string `json:"something"`
}
我想添加不在結構定義中的元素而不創建另一個結構類型。 例如
Struct.Extra1 = Nested{"yy"}
Struct.Nested.Extra2 = "zz"
這將導致
{
"Value": "xx",
"Value1": "xx",
"Extra1": {
"Something", "yy"
},
"Nest": {
"Something": "xx",
"Extra2": "zz"
}
}
SOLUTION1:我想添加omitempty
來實現這一點,但它使結構變得復雜。
type Struct struct {
Value string
Value1 string
Nest Nested
Extra1 Nested `json:"omitempty"`
}
type Nested struct {
Something string
Extra2 string `json:"omitempty"`
}
溶液2:
myextras := make(map[string]interface{})
// get Struct.Nested in map[string]interface{} format
myextras = Struct.Nest
myextras["Extra2"] = "zz"
// get Struct in map[string]interface{} format
struct["Nest"] = myextras
struct["Extra1"] = Nested{"yy"}
// solves the problem with lots of type casting but doesn't support json tag naming
是否有更好的解決方案來添加嵌套元素,這些元素在結構數據類型中沒有用json-tag支持表示,並且可以用於輸出給用戶。
根據這個答案: 我可以使用MarshalJSON將任意字段添加到golang中的json編碼嗎?
你可以做類似的事情(演示: http : //play.golang.org/p/dDiTwxhoNn ):
package main
import (
"encoding/json"
"fmt"
"log"
)
type Book struct {
Title string
Author string
// extra is used for additional dynamic element marshalling
extra func() interface{}
}
type FakeBook Book
func (b *Book) SetExtra(fn func() interface{}) {
b.extra = fn
}
func (b *Book) MarshalJSON() ([]byte, error) {
if b.extra == nil {
b.extra = func() interface{} { return *b }
}
return json.Marshal(b.extra())
}
func main() {
ms := &Book{
Title: "Catch-22",
Author: "Joseph Heller",
}
ms.SetExtra(func() interface{} {
return struct {
FakeBook
Extra1 struct {
Something string `json:"something"`
} `json:"extra1"`
}{
FakeBook: FakeBook(*ms),
Extra1: struct {
Something string `json:"something"`
}{
Something: "yy",
},
}
})
out, err := json.MarshalIndent(ms, "", " ")
if err != nil {
log.Fatalln(err)
}
fmt.Println(string(out))
mb := &Book{
Title: "Vim-go",
Author: "Fatih Arslan",
}
mb.SetExtra(func() interface{} {
return struct {
FakeBook
Something string `json:"something"`
}{
FakeBook: FakeBook(*mb),
Something: "xx",
}
})
out, err = json.MarshalIndent(mb, "", " ")
if err != nil {
log.Fatalln(err)
}
fmt.Println(string(out))
mc := &Book{
Title: "Another-Title",
Author: "Fatih Arslan",
}
out, err = json.MarshalIndent(mc, "", " ")
if err != nil {
log.Fatalln(err)
}
fmt.Println(string(out))
}
是。 有一個類型json.Raw,它不是結構而是[]字節。 你可以用任何元帥/ unmarshal方式管理它。
其他一切(比如json.RawMessage
字段無論如何都需要額外的編組步驟),地圖方法是唯一理智的方法。
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