Golang中用interface{}接收任何参数与强转

函数的传值中,interface{}是可以传任意参数的,就像java的object那样。
下面上我第一次想当然写的 ** 错误 **代码

package main
func main() {
 Any(2)
 Any("666")
}
func Any(v interface{}) {
 v1:=int(v)
 println(v1)
 
}

我只是想它能通过编译而已,因为上面的错误代码并没有任何的语法错误,心里只有666想说,下面是编译的错误提示:
cannot convert v (type interface {}) to type int: need type assertion
正确的代码就可以保证程序不出什么差错。

package main
func main() {
 Any(2)
 Any("666")
}
func Any(v interface{}) {
 if v2, ok := v.(string);ok{
 println(v2)
 }else if v3,ok2:=v.(int);ok2{
 println(v3)
 }
}

输出如下

2
666

不得不惊叹go的严谨啊。java写类似代码一下就编过去了。

无形之中我喷了java 好多好多,但它毕竟是20年前的语言,比我年纪还大,有些问题是真的没办法,现在基于jvm的kotlin,如果我当时没有放弃android的话,我想我现在的主要工作语言就是它了。

解释一下,为什么Golang有些情况下,强转可以,有点情况下,强转不可以:
其实stack overflow一个国外大神说的很好了,
原话+野生翻译

The reason why you cannot convert an interface typed value are these rules in the referenced specs parts:
Conversions are expressions of the form T(x) where T is a type and x is an expression that can be converted to type T.
A non-constant value x can be converted to type T in any of these cases:

• x is assignable to T.
• x's type and T have identical underlying types.
• x's type and T are unnamed pointer types and their pointer base types have identical underlying types.
• x's type and T are both integer or floating point types.
• x's type and T are both complex types.
• x is an integer or a slice of bytes or runes and T is a string type.
• x is a string and T is a slice of bytes or runes.
  But
  iAreaId := int(val)is not any of the cases 1.-7.

地址:关于interface{}做为参数

野生翻译如下:
我懒得翻了。。。。

本文来自:简书

感谢作者:送你一碗大麦茶

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