package my_struct
import (
"errors"
"reflect"
)
// 构造器
type Builder struct {
// 用于存储属性字段
fileId []reflect.StructField
}
func NewBuilder() *Builder {
return &Builder{
}
}
// 添加字段
func (b *Builder)AddField(field string,typ reflect.Type) *Builder {
b.fileId = append(b.fileId,reflect.StructField{
Name: field,Type: typ})
return b
}
// 根据预先添加的字段构建出结构体
func (b *Builder)Build() *Struct {
stu := reflect.StructOf(b.fileId)
index := make(map[string]int)
for i := 0; i < stu.NumField(); i++ {
index[stu.Field(i).Name] = i
}
return &Struct{
stu,index}
}
func (b *Builder) AddString(name string) *Builder {
return b.AddField(name, reflect.TypeOf(""))
}
func (b *Builder) AddBool(name string) *Builder {
return b.AddField(name, reflect.TypeOf(true))
}
func (b *Builder) AddInt64(name string) *Builder {
return b.AddField(name, reflect.TypeOf(int64(0)))
}
func (b *Builder) AddFloat64(name string) *Builder {
return b.AddField(name, reflect.TypeOf(float64(1.2)))
}
// 实际生成的结构体，基类
// 结构体的类型
type Struct struct {
typ reflect.Type
// <fieldName : 索引> // 用于通过字段名称，从Builder的[]reflect.StructField中获取reflect.StructField
index map[string]int
}
func (s Struct)New() *Instance {
return &Instance{
reflect.New(s.typ).Elem(),s.index}
}
// 结构体的值
type Instance struct {
instance reflect.Value
// <fieldName : 索引>
index map[string]int
}
var (
FieldNoExist error = errors.New("field no exist")
)
func (in Instance)Field(name string) (reflect.Value,error) {
if i,ok := in.index[name];ok{
return in.instance.Field(i),nil
}else {
return reflect.Value{
},FieldNoExist
}
}
func (in *Instance) SetString(name, value string) {
if i,ok := in.index[name];ok{
in.instance.Field(i).SetString(value)
}
}
func (in *Instance) SetBool(name string, value bool) {
if i,ok := in.index[name];ok{
in.instance.Field(i).SetBool(value)
}
}
func (in *Instance) SetInt64(name string, value int64) {
if i,ok := in.index[name];ok{
in.instance.Field(i).SetInt(value)
}
}
func (in *Instance) SetFloat64(name string, value float64) {
if i,ok := in.index[name];ok{
in.instance.Field(i).SetFloat(value)
}
}
func (i *Instance) Interface() interface{
} {
return i.instance.Interface()
}
func (i *Instance) Addr() interface{
} {
return i.instance.Addr().Interface()
}
运行测试：
func TestStruct(t *testing.T) {
pe := NewBuilder().
AddString("Name").
AddInt64("Age").
Build()
p := pe.New()
p.SetString("Name","你好")
p.SetInt64("Age",32)
fmt.Printf("%+v\n",p)
fmt.Printf("%T，%+v\n",p.Interface(),p.Interface())
fmt.Printf("%T，%+v\n",p.Addr(),p.Addr())
}
=== RUN TestStruct
&{
instance:{
typ:0xc00003e180 ptr:0xc0000045a0 flag:409} index:map[Age:1 Name:0]}
struct {
Name string; Age int64 }，{
Name:你好 Age:32}
*struct {
Name string; Age int64 }，&{
Name:你好 Age:32}
--- PASS: TestStruct (0.00s)
PASS