英文:
What is the difference between json.Marshal and json.MarshalIndent using Go?
问题
我想要以JSON格式输出CF命令的结果，但我不确定应该使用json.Marshal还是json.MarshalIndent。
我需要的输出格式如下：
{"key1": "value1",...."keyn": "valuen"}
这是一个旧的示例，但它不是我想要的输出格式：
cmd.ui.Say(terminal.EntityNameColor(T("User-Provided:")))for _, key := range keys {// cmd.ui.Say("%s: %v", key, envVars[key])这里需要一个新的示例，使用json.MarshalIndent}
我从未使用过Go语言，所以我真的不知道应该使用哪个函数以及如何使用。
英文:
I would like to get an output of a CF command in JSON format but I am not sure what to use either json.Marshal or json.MarshalIndent.
The output I need is like this:
{"key1": "value1",...."keyn": "valuen",}
This is the old example but it is not the desired output:
cmd.ui.Say(terminal.EntityNameColor(T("User-Provided:")))for _, key := range keys {// cmd.ui.Say("%s: %v", key, envVars[key])here needed a new one with json.marshalIdent}
I never used go so I really do not know which one to use and how.
答案1
得分: 16
我认为文档对此非常清楚。json.Marshal()和json.MarshalIndent()都会生成一个 JSON 文本结果（以[]byte形式），但前者会以紧凑的方式输出，没有缩进，而后者则应用了（可以自定义的）缩进。引用自json.MarshalIndent()的文档：
> MarshalIndent 类似于 Marshal，但会应用 Indent 来格式化输出。
看下面这个简单的例子：
type Entry struct {Key string `json:"key"`}e := Entry{Key: "value"}res, err := json.Marshal(e)fmt.Println(string(res), err)res, err = json.MarshalIndent(e, "", " ")fmt.Println(string(res), err)
输出结果是（在Go Playground上试一试）：
{"key":"value"} <nil>{"key": "value"} <nil>
还有json.Encoder：
type Entry struct {Key string `json:"key"`}e := Entry{Key: "value"}enc := json.NewEncoder(os.Stdout)if err := enc.Encode(e); err != nil {panic(err)}enc.SetIndent("", " ")if err := enc.Encode(e); err != nil {panic(err)}
输出结果是（在Go Playground上试一试）：
{"key":"value"}{"key": "value"}
英文:
I think the doc is pretty clear on this. Both json.Marshal()
and json.MarshalIndent() produces a JSON text result (in the form of a []byte), but while the former does a compact output without indentation, the latter applies (somewhat customizable) indent. Quoting from doc of json.MarshalIndent():
> MarshalIndent is like Marshal but applies Indent to format the output.
See this simple example:
type Entry struct {Key string `json:"key"`}e := Entry{Key: "value"}res, err := json.Marshal(e)fmt.Println(string(res), err)res, err = json.MarshalIndent(e, "", " ")fmt.Println(string(res), err)
The output is (try it on the Go Playground):
{"key":"value"} <nil>{"key": "value"} <nil>
There is also json.Encoder:
type Entry struct {Key string `json:"key"`}e := Entry{Key: "value"}enc := json.NewEncoder(os.Stdout)if err := enc.Encode(e); err != nil {panic(err)}enc.SetIndent("", " ")if err := enc.Encode(e); err != nil {panic(err)}
Output (try this one on the Go Playground):
{"key":"value"}{"key": "value"}
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