Use the json.MarshalIndent function in golang to convert the structure into a formatted JSON string

Use the json.MarshalIndent function in golang to convert the structure into a formatted JSON string

When writing programs using Golang, we often need to convert the structure into Convert to JSON string. In this process, the json.MarshalIndent function can help us achieve formatted output. Below we will explain in detail how to use this function and provide specific code examples.

First, let's create a structure containing some data. The following is the sample code:

package main

import (
    "encoding/json"
    "fmt"
)

type Person struct {
    Name  string `json:"name"`
    Age   int    `json:"age"`
    Email string `json:"email"`
}

func main() {
    person := Person{
        Name:  "John",
        Age:   30,
        Email: "john@example.com",
    }

    // 将Person结构体转换为JSON字符串
    jsonData, err := json.MarshalIndent(person, "", "  ")
    if err != nil {
        fmt.Println("转换为JSON字符串时发生错误:", err)
        return
    }

    // 打印格式化的JSON字符串
    fmt.Println(string(jsonData))
}

In the above code, we first define a Person structure containing name, age and email. Then create a Person object in the main function and convert the object to a JSON string using the json.MarshalIndent function.

When calling the json.MarshalIndent function, the function requires three parameters. The first parameter is the object to be converted, the second parameter is the prefix at the beginning of the line, and the third parameter is each indent. Level interval. In the example code, we set the second parameter to an empty string and the third parameter to two spaces. In this way, you can get a JSON string indented according to the specified format.

Finally, we use the fmt.Println function to print the formatted JSON string.

Run the above code and you will get the following output:

{
  "name": "John",
  "age": 30,
  "email": "john@example.com"
}

As we can see, it is very simple to use the json.MarshalIndent function to convert the structure into a formatted JSON string. We only need to specify some parameters to get a JSON string indented according to the specified format.

Summary:
In this article, we introduced how to use the json.MarshalIndent function in golang to convert a structure into a formatted JSON string. By giving suitable parameters, we can easily get the output in JSON format that meets the requirements. Whether it is converting a structure into a JSON string or parsing it from a JSON string into a structure, the encoding/json package in Golang's standard library provides many useful functions to facilitate JSON encoding and decoding operations.

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