002、GO之反射

01、反射字段和方法

package main

import (
    "fmt"
    "reflect"
)

type Name struct {
    name string
    age  int
}

func (n Name) Print() {
    fmt.Println(n.name)
}

func main() {
    n1 := Name{"abc", 10}
    Info(n1)
}

func Info(a interface{}) {
    t := reflect.TypeOf(a)
    v := reflect.ValueOf(a)

    fmt.Println("Type name:", t.Name())

    //不是struct类型时，获取不到Field信息
    if k := t.Kind(); k != reflect.Struct {
        fmt.Println("传入的类型不是struct类型")
        return
    }

    fmt.Println("字段")
    for i := 0; i < t.NumField(); i++ {
        f := t.Field(i)
        val := v.Field(i)
        fmt.Printf("%6s %v=%v
", f.Name, f.Type, val)
    }
    fmt.Println("方法", t.NumMethod())
    for i := 0; i< t.NumMethod(); i ++ {
        m := t.Method(i)
        fmt.Printf("%6s  %v
", m.Name, m.Type)
    }
}

02、反射匿名字段

package main

import (
    "fmt"
    "reflect"
)

type Name struct {
    name string
    age  int
}

type Person struct {
    Name
    job string
}

func main() {
    p := Person{
        Name: Name{"hello", 10},
        job:  "software engineer",
    }
    t := reflect.TypeOf(p)
    fmt.Printf("%#v
", t.FieldByIndex([]int{0,1}))
}

reflect.StructField{Name:"age", PkgPath:"main", Type:(*reflect.rtype)(0x4cda00), Tag:"", Offset:0x10, Index:[]int{1}, Anonymous:false}

03、反射修改值

package main

import (
    "fmt"
    "reflect"
)

type Name struct {
    Name string
    age  int
}

func main() {
    n := Name{"aaa", 10}
    v := reflect.ValueOf(&n)
    if v.Kind() != reflect.Ptr {
        fmt.Println("不可修改")
        return
    } else {
        v = v.Elem()
    }
    f := v.FieldByName("Name")
    if !f.IsValid() {
        fmt.Println("未找到字段")
        return
    }
    if !f.CanSet() {
        fmt.Println("找到的字段不可修改")
        return
    }
    if f.Kind() == reflect.String {
        f.SetString("abc")
    }
    fmt.Println(n)
}

04、反射调用方法

package main

import (
    "fmt"
    "reflect"
)

type Name struct {
    Name string
    age  int
}

func(n *Name) SetName(name string) {
    n.Name = name
}

func main() {
    n := Name{"aaa", 10}
    v := reflect.ValueOf(&n)
    vm := v.MethodByName("SetName")
    if !vm.IsValid() {
        fmt.Println("获取的方法不合法")
        return
    }
    vm.Call([]reflect.Value {reflect.ValueOf("abc")})
    fmt.Printf("%v", n)
}