go struct 与 json

https://golang.org/pkg/encoding/json/#pkg-index

成员标签-tag

https://sosedoff.com/2016/07/16/golang-struct-tags.html

Only data structures that can be represented as valid JSON will be encoded:

JSON objects only support strings as keys; to encode a Go map type it must be of the form map[string]T (where T is any Go type supported by the json package).
// JSON的key只能是string类型，所有在支持Map的情况下，需要其对应的Map的key是string类型。

Channel, complex, and function types cannot be encoded.
// 这些类型是无法被encoded的

Cyclic data structures are not supported; they will cause Marshal to go into an infinite loop.
// 循环数据类型无法被encoded

Pointers will be encoded as the values they point to (or 'null' if the pointer is nil).
// 指针类型可以被encoded
The json package only accesses the exported fields of struct types (those that begin with an uppercase letter). Therefore only the the exported fields of a struct will be present in the JSON output.
// 只能访问那些exported的struct types类型的field（大写字母开头的）

使用

encode

使用marshal方法进行编码。

func Marshal(v interface{}) ([]byte, error)

举例使用一个go定义的一个structure Message

type Message struct {
    Name string
    Body string
    Time int64
}

使用一个Message的实例被编码完以后的结果类似于下面

b == []byte(`{"Name":"Alice","Body":"Hello","Time":1294706395881547000}`)

编码中需要注意的内容

Only data structures that can be represented as valid JSON will be encoded:

JSON objects only support strings as keys; to encode a Go map type it must be of the form map[string]T (where T is any Go type supported by the json package).

// JSON的key只能是string类型，所有在支持Map的情况下，需要其对应的Map的key是string类型。

Channel, complex, and function types cannot be encoded.

// 这些类型是无法被encoded的

Cyclic data structures are not supported; they will cause Marshal to go into an infinite loop.

// 循环数据类型无法被encoded

Pointers will be encoded as the values they point to (or 'null' if the pointer is nil).

// 指针类型可以被encoded

The json package only accesses the exported fields of struct types (those that begin with an uppercase letter). Therefore only the the exported fields of a struct will be present in the JSON output.

// 只能访问那些exported的struct types类型的field（大写字母开头的）

decode

https://blog.golang.org/json-and-go