反射与网络

Catalogue

1. 1. 反射基本操作
2. 2. 反射获取结构体字段和方法调用
3. 3. 反射设置结构体字段的值
4. 4. 反射实现适配器
5. 5. 参考资料

反射基本操作

package main

import (
	"fmt"
	"reflect"
)

func main()  {

	// 反射对基本类型操作
	//var num int = 10
	//testReflect01(num)

	// 反射对结构体操作
	//var stu = Student{
	//	Name: "fuyi",
	//	Age:  22,
	//}
	//testReflect02(stu)

	var num int = 10
	testReflect03(&num)
	fmt.Printf("num: %v\n", num)
}

func testReflect01(i interface{})  {
	rType := reflect.TypeOf(i)
	fmt.Printf("rType : %v, %T\n", rType, rType)

	rVal := reflect.ValueOf(i)
	fmt.Printf("rVal : %v, %T\n", rVal, rVal)

	// rVal转interface
	iV := rVal.Interface()

	// 通过断言转具体类型
	n := iV.(int)
	fmt.Println("n : ", n + 1)
}

type Student struct {
	Name string
	Age int
}

func testReflect02(i interface{}) {
	rType := reflect.TypeOf(i)
	fmt.Printf("rType : %v, %T\n", rType, rType)

	rVal := reflect.ValueOf(i)
	fmt.Printf("rVal : %v, %T\n", rVal, rVal)

	fmt.Printf("kind: rType=%v, rVal=%v\n", rType.Kind(), rVal.Kind())

	iV := rVal.Interface()
	stu, ok := iV.(Student)
	if ok {
		fmt.Printf("stu: %v, %v, %v", stu, stu.Name, stu.Age)
	}
}

func testReflect03(i interface{})  {
	rVal := reflect.ValueOf(i)
	rVal.Elem().SetInt(20)
}

反射获取结构体字段和方法调用

package main

import (
	"reflect"
	"fmt"
)

type Monster struct {
	Name string `json:"name"`
	Age int `json:"monster_age"`
	Score float32
	Sex string
}

func (m Monster) Print()  {
	fmt.Println("---start---")
	fmt.Println(m)
	fmt.Println("---end---")
}

func (m Monster) GetSum(n1, n2 int) int {
	return n1 + n2
}

func (m Monster) SetVal(name string, age int, score float32, sex string)  {
	m.Name = name
	m.Age = age
	m.Score = score
	m.Sex = sex
}

func TestReflect(i interface{})  {
	rTyp := reflect.TypeOf(i)
	rVal := reflect.ValueOf(i)
	kd := rVal.Kind()
	if kd != reflect.Struct {
		fmt.Println("expect struct")
		return
	}
	numField := rVal.NumField()
	fmt.Printf("numField: %v\n", numField)

	for j := 0; j < numField; j++  {
		sf := rTyp.Field(j)
		fmt.Printf("Field: index = %v, val = %v, type = %v, tag = %v\n", j, rVal.Field(j), sf.Name, sf.Tag)
	}

	numMethod := rVal.NumMethod()
	fmt.Printf("numMethod: %v\n", numMethod)

	// 该索引按ASCII排序，即调用Print方法
	rVal.Method(1).Call(nil)

	var params []reflect.Value;
	params = append(params, reflect.ValueOf(10))
	params = append(params, reflect.ValueOf(20))
	result := rVal.Method(0).Call(params)
	fmt.Printf("result: %v", result[0].Int())
}



func main()  {
	//m := Monster{
	//	Name:  "Lizhuo",
	//	Age:   22,
	//	Score: 93.3,
	//	Sex:   "man",
	//}
	//TestReflect(m)

}

反射设置结构体字段的值

package main

import (
	"reflect"
	"fmt"
)

type User struct {
	Name string
	Age int
}

func main()  {
	var (
		user *User
		rVal reflect.Value
	)
	user = &User{}
	rVal = reflect.ValueOf(user)
	rVal = rVal.Elem()

	rVal.FieldByName("Name").SetString("fuyi")
	rVal.FieldByName("Age").SetInt(88)

	fmt.Printf("user: %v", user)
}

反射实现适配器

package main

import (
	"reflect"
	"fmt"
)

func call1(n1, n2 int) {
	fmt.Printf("call1 params: %v,%v\n", n1,n2)
}

func call2(n1,n2 int, s1 string) {
	fmt.Printf("call2 params: %v,%v, %v\n", n1,n2, s1)
}

func bridge(call interface{}, args ...interface{})  {
	var rArgs []reflect.Value
	for i := 0; i < len(args); i++ {
		rArgs = append(rArgs, reflect.ValueOf(args[i]))
	}
	reflect.ValueOf(call).Call(rArgs)
}

func main()  {

	bridge(call1, 1, 2)
	bridge(call2, 1, 2, "haha")
}

参考资料