package main
import (
"encoding/json"
"errors"
"fmt"
"reflect"
"strconv"
"time"
)
type User struct {
a string
b string
}
type S struct {
User
Name string
Age int
Address string
}
//结构体转map方法1
func Struct2Map(obj interface{}) map[string]interface{} {
t := reflect.TypeOf(obj)
v := reflect.ValueOf(obj)
var data = make(map[string]interface{})
//func (v Value) NumField() int, 返回v持有的结构体类型值的字段数，如果v的Kind不是Struct会panic
for i := 0; i < t.NumField(); i++ {
data[t.Field(i).Name] = v.Field(i).Interface()
}
return data
}
//结构体转map方法2
func StructToMapViaJson(data S) map[string]interface{} {
m := make(map[string]interface{})
//struct 转json
j, _ := json.Marshal(data)
//json 转map
json.Unmarshal(j, &m)
return m
}
func FillStruct(data map[string]interface{}, obj interface{}) error {
for k, v := range data {
//fmt.Println("k: ", k, " v: ", v)
err := SetField(obj, k, v)
if err != nil {
return err
}
}
return nil
}
func SetField(obj interface{}, k string, v interface{}) error {
//结构体属性值
structValue := reflect.ValueOf(obj).Elem()
//fmt.Println("structValue: ", structValue)
//结构体单个属性值
structFieldValue := structValue.FieldByName(k)
//fmt.Println("structFieldValue: ", structFieldValue)
if !structFieldValue.IsValid() {
return fmt.Errorf("No such field: %s in obj", k)
}
if !structFieldValue.CanSet() {
return fmt.Errorf("Cannot set %s field value", k)
}
//结构体属性类型
structFieldType := structFieldValue.Type()
val := reflect.ValueOf(v)
var err error
if structFieldType != val.Type() {
//类型转换
val, err = TypeConversion(fmt.Sprintf("%v", v), structFieldValue.Type().Name())
if err != nil {
return err
}
}
structFieldValue.Set(val)
return nil
}
func TypeConversion(value string, ntype string) (reflect.Value, error) {
fmt.Println("call TypeConversion...")
if ntype == "string" {
return reflect.ValueOf(value), nil
} else if ntype == "time.Time" {
t, err := time.ParseInLocation("2006-01-02 15:04:05", value, time.Local)
return reflect.ValueOf(t), err
} else if ntype == "Time" {
t, err := time.ParseInLocation("2006-01-02 15:04:05", value, time.Local)
return reflect.ValueOf(t), err
} else if ntype == "int" {
i, err := strconv.Atoi(value)
return reflect.ValueOf(i), err
} else if ntype == "int8" {
i, err := strconv.ParseInt(value, 10, 64)
return reflect.ValueOf(int8(i)), err
} else if ntype == "int32" {
i, err := strconv.ParseInt(value, 10, 64)
return reflect.ValueOf(int64(i)), err
} else if ntype == "int64" {
i, err := strconv.ParseInt(value, 10, 64)
return reflect.ValueOf(i), err
} else if ntype == "float32" {
i, err := strconv.ParseFloat(value, 64)
return reflect.ValueOf(float32(i)), err
} else if ntype == "float64" {
i, err := strconv.ParseFloat(value, 64)
return reflect.ValueOf(i), err
}
//else if .......增加其他一些类型的转换
return reflect.ValueOf(value), errors.New("未知的类型：" + ntype)
}
func main() {
var s S
Types := reflect.TypeOf(s)
//TypeData.FieldByIndex([]int{}) 返回 StructField
//[]int{}参数: 第一个是struct类型的索引(如果索引为参数一的数据类型不是struct会报错), 第二个是索引为参数一的结构体内属性的索引
//例如[]int{0,0} 会输出[0] a string，表示索引为0的结构体User内索引为0的数据是a
//[]int{0, 1} 会输出[1] b string
//[]int{1, 0}会报错, 因为索引为1的数据是S结构体中的数据 Name string，数据类型不是struct
res := Types.FieldByIndex([]int{0, 0})
fmt.Println("FieldByIndex: ", res.Index, res.Name, res.Type)
//struct to map
info := S{Name: "xsk", Age: 22, Address: "shanghai"}
data := Struct2Map(info)
fmt.Println("data: ", data, " ", "typeof(data): ", reflect.TypeOf(data))
for k, v := range data {
fmt.Println(k, v.(interface{}))
}
fmt.Println("---------")
data1 := StructToMapViaJson(info)
fmt.Println("data1: ", data1, " ", "typeof(data1): ", reflect.TypeOf(data1))
for k, v := range data1 {
fmt.Println(k, v.(interface{}))
}
fmt.Println("---------")
//map to struct
data2 := make(map[string]interface{})
data2["Name"] = "xsk"
data2["Age"] = 22
data2["Address"] = "shanghai"
result := &S{}
err := FillStruct(data2, result)
fmt.Println("err: ", err, " result: ", fmt.Sprintf("%+v", *result))
fmt.Println("---------")
//map[string]*Struct 下面几种初始化都行
//第一种
//var info1 = map[string]*S{"info": &S{Name: "mtt", Age: 23, Address: "shanghai"}}
//第二种
var info1 = map[string]*S{"info": &S{}, "other": &S{}}
info1["info"].Name = "mtt"
info1["info"].Age = 23
info1["info"].Address = "shanghai"
fmt.Println("info1: ", *info1["info"])
t := reflect.TypeOf(*info1["info"])
v := reflect.ValueOf(*info1["info"])
for k := 0; k < t.NumField(); k++ {
fmt.Printf("%s: %v\n", t.Field(k).Name, v.Field(k).Interface())
}
fmt.Println("---------")
//第三种
var info2 = map[string]*S{}
info2["info"] = &S{Name: "xly", Age: 1, Address: "shanghai"}
fmt.Println("info2: ", *info2["info"])
ty := reflect.TypeOf(*info2["info"])
vl := reflect.ValueOf(*info2["info"])
for k := 0; k < ty.NumField(); k++ {
fmt.Printf("%s: %v\n", ty.Field(k).Name, vl.Field(k).Interface())
}
}
golang 中 map 转 struct
package main
import (
"fmt"
"github.com/goinggo/mapstructure"
)
type Person struct {
Name string
Age int
}
func MapToStruct() {
mapInstance := make(map[string]interface{})
mapInstance["Name"] = "liang637210"
mapInstance["Age"] = 28
var person Person
//将 map 转换为指定的结构体
if err := mapstructure.Decode(mapInstance, &person); err != nil {
fmt.Println(err)
}
fmt.Printf("map2struct后得到的 struct 内容为:%v", person)
}
func main(){
MapToStruct()
}