import (
    "encoding/json"
    "fmt"
    "math/big"
)
func main() {
    jsonStr := `{"number": "9223372036854775808"}` // 超出int64范圍的數(shù)字
    var data map[string]json.Number
    err := json.Unmarshal([]byte(jsonStr), &data)
    if err != nil {
        panic(err)
    }
    number := data["number"]
    num := new(big.Int)
    num, ok := number.Int64()
    if !ok {
        num, _ = new(big.Int).SetString(string(number), 10)
        fmt.Printf("轉(zhuǎn)換為big.Int: %s\n", num.String())
    } else {
        fmt.Printf("轉(zhuǎn)換為int64: %d\n", num)
    }
}

jsoniter "github.com/json-iterator/go"
func Test0008_Jsoniter_Marshal(t *testing.T) {
    order := Order{
       Id:         baseutils.SnowflakeNextVal(),
       OrderId:    "12345678",
       Money:      99.99,
       CreateTime: time.Now(), // 2023-12-05T16:19:33.943989108+08:00
       Extend:     map[string]string{"name": "張三"},
    }
    // 使用1:直接轉(zhuǎn)成字符串
    jsonStr, _ := jsoniter.MarshalToString(order)
    fmt.Println("jsonStr:", jsonStr)
    // 使用2:直接轉(zhuǎn)成字節(jié)數(shù)組
    jsonByteArr, _ := jsoniter.Marshal(order)
    fmt.Println("jsonByteArr:", jsonByteArr)
    // 使用3:反序列化之字符串轉(zhuǎn)結(jié)構(gòu)體
    str := `{"id":666, "order_id":"12345678", "money": 99.99, "create_time":"2023-12-05T16:19:33.943989108+08:00", "extend":{"name":"張三"}}`
    var order2 Order
    err := jsoniter.UnmarshalFromString(str, &order2)
    if err != nil {
       fmt.Println("err2:", err)
    }
    fmt.Println("order2:", order2)
    // 使用4:反序列化之字節(jié)數(shù)組轉(zhuǎn)結(jié)構(gòu)體
    var order3 Order
    var jsonNew = jsoniter.ConfigCompatibleWithStandardLibrary
    // 自適應(yīng)類型
    extra.RegisterFuzzyDecoders()
    err = jsonNew.Unmarshal(jsonByteArr, &order3)
    if err != nil {
       fmt.Println("err3:", err)
    }
    fmt.Println("order3:", order3)
}
???????order3: {572839995925069824 12345678 99.99 2024-04-29 17:41:37.8819085 +0800 CST map[name:張三]}

package main
import (
	"encoding/json"
	"fmt"
)
type MyData struct {
	// 將可能超限的整數(shù)字段聲明為 json.Number
	LargeID json.Number `json:"id"`
}
func main() {
	jsonStr := `{"id": 9223372036854775807}`
	var data MyData
	if err := json.Unmarshal([]byte(jsonStr), &data); err != nil {
		panic(err)
	}
	// 安全地將 json.Number 轉(zhuǎn)換為 int64
	id, err := data.LargeID.Int64()
	if err != nil {
		panic(err) // 處理轉(zhuǎn)換錯誤
	}
	fmt.Printf("轉(zhuǎn)換后的 int64 值: %d\n", id)
}

package main

import (
	"encoding/json"
	"fmt"
)

type MyData struct {
	// 使用 json:",string" 標(biāo)簽，讓 ID 在 JSON 中以字符串形式傳遞
	LargeID int64 `json:"id,string"`
}

func main() {
	jsonStr := `{"id": "9223372036854775807"}`
	var data MyData
	if err := json.Unmarshal([]byte(jsonStr), &data); err != nil {
		panic(err)
	}
	fmt.Printf("Unmarshal 得到的 int64 值: %d\n", data.LargeID)
}

package main

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

// 定義一個新的類型，并為其實現(xiàn) UnmarshalJSON 接口
type PreciseInt int64

func (pi *PreciseInt) UnmarshalJSON(b []byte) error {
	// 1. 先解析到 json.Number
	var n json.Number
	if err := json.Unmarshal(b, &n); err != nil {
		return err
	}
	// 2. 再從 json.Number 安全地轉(zhuǎn)換為 int64
	i, err := n.Int64()
	if err != nil {
		return err
	}
	*pi = PreciseInt(i)
	return nil
}

type MyData struct {
	LargeID PreciseInt `json:"id"`
}

func main() {
	jsonStr := `{"id": 9223372036854775807}`
	var data MyData
	if err := json.Unmarshal([]byte(jsonStr), &data); err != nil {
		panic(err)
	}
	fmt.Printf("轉(zhuǎn)換后的 int64 值: %d\n", data.LargeID)
}