将DynamoDB的JSON转换为AttributeValue、Go对象或JSON。

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英文:

Convert DynamoDB JSON to AttributeValue, Go Object or Json

问题

我正在尝试将简单的DynamoDB对象字符串转换为dynamodb.AttributeValue,然后映射到一个Go对象(Go类型结构),或者转换为一个简单的JSON Go对象。

我认为,在Java中有类似的答案(123),但我没有在Golang中找到类似的实现。

英文:

I am trying to convert simple DynamoDB Object string:

{
  "Item": {
    "Id": {
      "S": "db31"
    },
    "CreateTime": {
      "N": "1647882237618915000"
    }
}

to either dynamodb.AttributeValue and then map to a go object (go type structure) or convert to a simple JSON go object.

I think, there are similar answers (1, 2, 3) in Java, but I didn't find a similar implementation in Golang.

答案1

得分: 2

你可以创建一个结构体类型,并使用json.Unmarshal来解析JSON字符串,代码如下:

package main

import (
	"encoding/json"
	"fmt"
	"os"
)

type Record struct {
	Item struct {
		Id struct {
			S string
		}
		CreateTime struct {
			N string
		}
	}
}

func main() {

	str := `{
  "Item": {
    "Id": {
      "S": "db31"
    },
    "CreateTime": {
      "N": "1647882237618915000"
    }
  }
}`

	var record Record
	if err := json.Unmarshal([]byte(str), &record); err != nil {
		fmt.Fprintf(os.Stderr, "unmarshal failed: %v", err)
		os.Exit(1)
	}

	fmt.Printf("%s %s", record.Item.Id.S, record.Item.CreateTime.N)
}

如果你想采用不同的方法,并将结果转换为与JSON不同的结构体,你可以使用类似gjson的库。下面是一个将结果“展平”为更简单的结构体的示例:

package main

import (
	"fmt"
	"github.com/tidwall/gjson"
)

type Record struct {
	Id         string
	CreateTime string
}

func main() {

	str := `{
  "Item": {
    "Id": {
      "S": "db31"
    },
    "CreateTime": {
      "N": "1647882237618915000"
    }
  }
}`

	values := gjson.GetMany(str, "Item.Id.S", "Item.CreateTime.N")

	record := Record{
		Id:         values[0].Str,
		CreateTime: values[1].Str,
	}

	fmt.Printf("%s %s", record.Id, record.CreateTime)
}

希望对你有帮助!

英文:

You could create a struct type and use json.Unmarshal to unmarshal the JSON string like this:

package main

import (
	"encoding/json"
	"fmt"
	"os"
)

type Record struct {
	Item struct {
		Id struct {
			S string
		}
		CreateTime struct {
			N string
		}
	}
}

func main() {

	str := `{
  "Item": {
    "Id": {
      "S": "db31"
    },
    "CreateTime": {
      "N": "1647882237618915000"
    }
  }
}`

	var record Record
	if err := json.Unmarshal([]byte(str), &record); err != nil {
		fmt.Fprintf(os.Stderr, "unmarshal failed: %v", err)
		os.Exit(1)
	}

	fmt.Printf("%s %s", record.Item.Id.S, record.Item.CreateTime.N)
}


If you want a different approach, and want to transform the result into a structure that is different than the JSON, you could use a library like gjson.

Here is an example "flattening" the result into a simpler struct:

package main

import (
	"fmt"
	"github.com/tidwall/gjson"
)

type Record struct {
	Id         string
	CreateTime string
}

func main() {

	str := `{
  "Item": {
    "Id": {
      "S": "db31"
    },
    "CreateTime": {
      "N": "1647882237618915000"
    }
  }
}`

	values := gjson.GetMany(str, "Item.Id.S", "Item.CreateTime.N")

	record := Record{
		Id:         values[0].Str,
		CreateTime: values[1].Str,
	}

	fmt.Printf("%s %s", record.Id, record.CreateTime)
}

huangapple
  • 本文由 发表于 2022年12月1日 09:21:50
  • 转载请务必保留本文链接:https://go.coder-hub.com/74635931.html
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