golang struct match all field

應用場景：json.Unmarshal前檢查結構體字段是否全匹配

package main

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

type A struct {
    X int
    Y string
}

type B struct {
    X int
    Y string
    Z string
}

func MatchUnmarshal(data []byte, v interface{}) bool {
    var (
        m   map[string]interface{}
        err error
    )

    //輸入的結構體轉爲map
    _ = json.Unmarshal(data, &m)

    //返回interface或者指針中的值
    value := reflect.ValueOf(v).Elem()

    //反射出類型
    t := value.Type()

    //t.NumField() 字段數量
    for i := 0; i < t.NumField(); i++ {
        field := t.Field(i)

        //是否在輸入結構體中存在
        _, ok := m[field.Name]

        if !ok {
            return  false
        }

        delete(m, field.Name)
    }

    //輸入結構體字段比結構結構體字段多
    if len(m) > 0 {
        return  false
    }

    if err = json.Unmarshal(data, v); nil != err {
        return false
    }

    return true
}

func main() {

    a := A{
        X: 1,
        Y: "2",
    }

    b := B{
        X: 1,
        Y: "2",
        Z: "3",
    }

    //構造兩個輸入結構體
    dataA, _ := json.Marshal(a)
    dataB, _ := json.Marshal(b)

    var (
        a1          A
        success     bool
    )

    if success = MatchUnmarshal(dataA, &a1); !success {
        fmt.Println("dataA param input error")
    }

    if success = MatchUnmarshal(dataB, &a1); !success {
        fmt.Println("dataB param input error")
    }
}