Go结构字段的第三个参数是什么? [英] What is the third parameter of a Go struct field?
问题描述
type Config struct {
CommitIndex uint64 `json:"commitIndex"`
// TODO decide what we need to store in peer struct
Peers []*Peer `json:"peers"`
}
我知道前两列是什么,但是json:"commitIndex"
是什么?
I understand what the first two columns are,but what is json:"commitIndex"
?
推荐答案
它称为struct标记,可以使用 reflect
程序包在运行时.
It's called a struct tag, they can be parsed using the reflect
package at runtime.
来自 https://golang.org/ref/spec#Struct_types :
字段声明之后可以是可选的字符串文字标签,该标签将成为相应字段声明中所有字段的属性.
A field declaration may be followed by an optional string literal tag, which becomes an attribute for all the fields in the corresponding field declaration.
可以通过反射界面使这些标签可见,并且可以使用这些结构的类型标识,但否则将被忽略.
The tags are made visible through a reflection interface and take part in type identity for structs but are otherwise ignored.
一些使用反射的软件包,例如 json
和
Some packages that use reflection like json
and xml
use tags to handle special cases better.
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