前面关于复杂类型的转换功能如果大家觉得还不够的话，那么您可以了解下Scan转换方法，该方法可以实现对任意参数到struct/struct数组/map/map数组的转换，并且根据开发者输入的转换目标参数自动识别执行转换。

该方法定义如下：

// Scan automatically calls MapToMap, MapToMaps, Struct or Structs function according to
// the type of parameter `pointer` to implement the converting.
// It calls function MapToMap if `pointer` is type of *map to do the converting.
// It calls function MapToMaps if `pointer` is type of *[]map/*[]*map to do the converting.
// It calls function Struct if `pointer` is type of *struct/**struct to do the converting.
// It calls function Structs if `pointer` is type of *[]struct/*[]*struct to do the converting.
func Scan(params interface{}, pointer interface{}, mapping ...map[string]string) (err error)

我们接下来看几个示例便可快速理解。

自动识别转换Struct

package main

import (
	"github.com/gogf/gf/v2/frame/g"
	"github.com/gogf/gf/v2/util/gconv"
)

func main() {
	type User struct {
		Uid  int
		Name string
	}
	params := g.Map{
		"uid":  1,
		"name": "john",
	}
	var user *User
	if err := gconv.Scan(params, &user); err != nil {
		panic(err)
	}
	g.Dump(user)
}

执行后，输出结果为：

{
	"Name": "john",
	"Uid": 1
}

自动识别转换Struct数组

package main

import (
	"github.com/gogf/gf/v2/frame/g"
	"github.com/gogf/gf/v2/util/gconv"
)

func main() {
	type User struct {
		Uid  int
		Name string
	}
	params := g.Slice{
		g.Map{
			"uid":  1,
			"name": "john",
		},
		g.Map{
			"uid":  2,
			"name": "smith",
		},
	}
	var users []*User
	if err := gconv.Scan(params, &users); err != nil {
		panic(err)
	}
	g.Dump(users)
}

执行后，终端输出：

[
    {
            "Uid": 1,
            "Name": "john"
    },
    {
            "Uid": 2,
            "Name": "smith"
    }
]

自动识别转换Map

package main

import (
	"github.com/gogf/gf/v2/frame/g"
	"github.com/gogf/gf/v2/util/gconv"
)

func main() {
	var (
		user   map[string]string
		params = g.Map{
			"uid":  1,
			"name": "john",
		}
	)
	if err := gconv.Scan(params, &user); err != nil {
		panic(err)
	}
	g.Dump(user)
}

执行后，输出结果为：

{
   "Uid": "1", 
   "Name": "john"
}

自动识别转换Map数组

package main

import (
	"github.com/gogf/gf/v2/frame/g"
	"github.com/gogf/gf/v2/util/gconv"
)

func main() {
	var (
		users  []map[string]string
		params = g.Slice{
			g.Map{
				"uid":  1,
				"name": "john",
			},
			g.Map{
				"uid":  2,
				"name": "smith",
			},
		}
	)
	if err := gconv.Scan(params, &users); err != nil {
		panic(err)
	}
	g.Dump(users)
}

执行后，输出结果为：

[
    {
            "name": "john",
            "uid": "1"
    },
    {
            "name": "smith",
            "uid": "2"
    }
]
















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2 Comments

  1. 吕下阿蒙

    gjson.Json在继承的结构体中使用gconv.Scan转换，会导致值丢失，其他类型正常，请问这个该怎么解决？

    代码如下：
    type Test struct {
       Id        int64       `json:"id"          description:""`
       Flag      *gjson.Json `json:"flag"        description:"标签"`
       Title     string      `json:"title"       description:"标题"`
       Status    int         `json:"status"      description:"状态"`
       CreatedAt *gtime.Time `json:"createdAt"   description:"创建时间"`
       UpdatedAt *gtime.Time `json:"updatedAt"   description:"修改时间"`
    }

    var (
       A *Test
       B *Test
    )

    A = &Test{
       Id:        2,
       Flag:      gjson.New("[\"1\", \"2\"]"),
       Title:     "测试",
       Status:    1,
       CreatedAt: gtime.Now(),
       UpdatedAt: gtime.Now(),
    }

    type Test2 struct {
       Test
    }
    type Test3 struct {
       Test
    }
    var (
       A2 Test2
       B2 Test3
    )

    if err = gconv.Scan(A, &B); err != nil {
       return nil, err
    }
    g.DumpWithType("A", A)
    g.DumpWithType("B", B)

    if err = gconv.Scan(B, &A2); err != nil {
       return nil, err
    }
    g.DumpWithType("A2", A2)

    if err = gconv.Scan(A2, &B2); err != nil {
       return nil, err
    }
    g.DumpWithType("B2", B2)



    结果如下：

    string(1) "A"
    *admin.Test(6) {
        Id:        int64(2),
        Flag:      *gjson.Json(13) "[\"1\",\"2\"]",
        Title:     string(6) "测试",
        Status:    int(1),
        CreatedAt: *gtime.Time(19) "2022-12-29 18:14:55",
        UpdatedAt: *gtime.Time(19) "2022-12-29 18:14:55",
    }
    string(1) "B"
    *admin.Test(6) {
        Id:        int64(2),
        Flag:      *gjson.Json(13) "[\"1\",\"2\"]",
        Title:     string(6) "测试",
        Status:    int(1),
        CreatedAt: *gtime.Time(19) "2022-12-29 18:14:55",
        UpdatedAt: *gtime.Time(19) "2022-12-29 18:14:55",
    }
    string(2) "A2"
    admin.Test2(6) {
        Id:        int64(2),
        Flag:      *gjson.Json(13) "[\"1\",\"2\"]",
        Title:     string(6) "测试",
        Status:    int(1),
        CreatedAt: *gtime.Time(19) "2022-12-29 18:14:55",
        UpdatedAt: *gtime.Time(19) "2022-12-29 18:14:55",
    }
    string(2) "B2"
    admin.Test3(6) {
        Id:        int64(2),
        Flag:      *gjson.Json(4) "null",
        Title:     string(6) "测试",
        Status:    int(1),
        CreatedAt: *gtime.Time(19) "2022-12-29 18:14:55",
        UpdatedAt: *gtime.Time(19) "2022-12-29 18:14:55",
    }





  2. 梦想与现实-广州大智汇

    自动识别转换Map例子输出的数据有误

    应该是

    {
    "uid":  "1",
    "name": "john",
}