golang 结构体复制库 Copier

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type Copier1 struct {
	Name  string
	Age   int32
	Hobby string
}
type Copier2 struct {
	Name string
	Age  int32
}
type Copier3 struct {
	Hobby string
}
v1 := &Copier1{Name: "zs", Age: 20}
v2 := &Copier2{Name: "ls", Age: 30}
copier.Copy(v1, v2)
fmt.Printf("%#v\n", v1)

// 会将v3置为默认值
v3 := &Copier1{Name: "zs", Age: 20}
v4 := &Copier2{}
copier.Copy(v3, v4)
fmt.Printf("%#v\n", v3)

// 将一个nil值的内容复制到v5,并不会将v5置为nil
v5 := &Copier1{Name: "zs", Age: 20}
var v6 *Copier2
copier.Copy(v5, v6)
fmt.Printf("%#v\n", v5)

// 将多个值copy到同一个结构体中
v7 := &Copier3{Hobby: "swim"}
v6 = &Copier2{Name: "we", Age: 50}
copier.Copy(v5, v6)
copier.Copy(v5, v7)
fmt.Printf("%#v\n", v5)

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# 直接复制，新值替换旧值
&main.Copier1{Name:"ls", Age:30, Hobby:""}
# 空值复制，新值替换旧值
&main.Copier1{Name:"", Age:0, Hobby:""}
# nil复制，旧值保持不变
&main.Copier1{Name:"zs", Age:20, Hobby:""}
# 多个新值复制，新值先后影响到相关字段
&main.Copier1{Name:"we", Age:50, Hobby:"swim"}