feat(reflect): 添加结构体反射检查和字段操作功能

- 新增 inspectStructs 函数用于检查多个结构体类型
- 实现 inspectStructType递归检查结构体字段信息
- 添加 describeField 函数描述指定字段及其父级信息
- 新增 inspectTags 函数检查结构体标签信息
- 实现 getFieldValues 和 setFieldValues 操作结构体字段值
- 在 main.go 中调用新增的 main25、main26、main27 示例函数
- 扩展 types.go 中的结构体定义以支持新功能演示

27-reflection/reflection/main.go

@@ -22,4 +22,7 @@ func main() {
 	main22()
 	main23()
 	main24()
+	main25()
+	main26()
+	main27()
 }

27-reflection/reflection/re2.go

@@ -314,3 +314,141 @@ func main24() {
 		Printfln("Key: %v, Value: %v", key, val)
 	}
 }
+
+func inspectStructs(structs ...interface{}) {
+	for _, s := range structs {
+		structType := reflect.TypeOf(s)
+		if structType.Kind() == reflect.Struct {
+			inspectStructType("main", []int{}, structType, structType)
+		}
+	}
+}
+
+func inspectStructType(tag string, baseIndex []int, structType reflect.Type, baseType reflect.Type) {
+	Printfln("--- %v Struct Type: %v", tag, structType)
+	for i := 0; i < structType.NumField(); i++ {
+		fieldIndex := append(baseIndex, i)
+		field := structType.Field(i)
+		Printfln("%v - Field Base Index : %v , Field Index %v: Name:%v, Type:%v, Tag:%v , PkgPath:%v",
+			tag, fieldIndex, field.Index, field.Name, field.Type, field.Tag, field.PkgPath)
+
+		if field.Type.Kind() == reflect.Struct {
+			inspectStructType("field", fieldIndex, field.Type, baseType)
+
+			fieldWithFieldIndex := baseType.FieldByIndex(fieldIndex)
+			inspectStructType("fieldWithFieldIndex", fieldIndex, fieldWithFieldIndex.Type, baseType)
+		}
+
+	}
+	Printfln("--- End %v Struct Type: %v", tag, structType)
+}
+
+func describeField(s interface{}, fieldName string) {
+	Printfln("\ndescribeField:")
+	structType := reflect.TypeOf(s)
+	field, found := structType.FieldByName(fieldName)
+	if found {
+		Printfln("Top-Level Type: %v, Name: %v, Type: %v, Index: %v, Tag:%v , PkgPath:%v",
+			structType, field.Name, field.Type, field.Index, field.Tag, field.PkgPath)
+		index := field.Index
+
+		for len(index) > 1 {
+			index = index[0 : len(index)-1]
+			parentField := structType.FieldByIndex(index)
+			Printfln("Parent  Name: %v, Type: %v, Index: %v, Tag:%v , PkgPath:%v",
+				parentField.Name, parentField.Type, parentField.Index, parentField.Tag, parentField.PkgPath)
+		}
+	} else {
+		Printfln("Field %v not found", fieldName)
+	}
+}
+
+func main25() {
+	Printfln("\nmain25:")
+
+	inspectStructs(Purchase{})
+
+	describeField(Purchase{}, "Price")
+}
+
+func inspectTags(s interface{}, tagName string) {
+	structType := reflect.TypeOf(s)
+	for i := 0; i < structType.NumField(); i++ {
+		field := structType.Field(i)
+		tag := field.Tag
+
+		valGet := tag.Get(tagName)
+		valLookup, ok := tag.Lookup(tagName)
+
+		Printfln("Field Name: %v, Type: %v, Tag: %v, TagName: %v, Get: %v, Lookup: %v, LookupOk: %v",
+			field.Name, field.Type, tag, tagName, valGet, valLookup, ok)
+	}
+}
+
+func main26() {
+	Printfln("\nmain26:")
+	inspectTags(Person{}, "alias")
+
+	stringType := reflect.TypeOf("")
+	structType := reflect.StructOf([]reflect.StructField{
+		{Name: "Name", Type: stringType, Tag: `alias:"id"`},
+		{Name: "City", Type: stringType, Tag: `alias:""`},
+		{Name: "Country", Type: stringType},
+	})
+	inspectTags(reflect.New(structType), "alias")
+	inspectTags(reflect.New(structType).Elem().Interface(), "alias")
+}
+
+func getFieldValues(s interface{}) {
+	structValue := reflect.ValueOf(s)
+	if structValue.Kind() != reflect.Struct {
+		Printfln("Not a struct")
+		return
+	}
+	for i := 0; i < structValue.NumField(); i++ {
+		fieldType := structValue.Type().Field(i)
+		fieldVal := structValue.Field(i)
+		Printfln("Name: %v, Type: %v, Value: %v", fieldType.Name, fieldType.Type, fieldVal)
+	}
+}
+
+func setFieldValues(s interface{}, newVals map[string]interface{}) {
+	structValue := reflect.ValueOf(s)
+	if structValue.Kind() != reflect.Ptr || structValue.Elem().Kind() != reflect.Struct {
+		Printfln("Not a pointer to a struct")
+		return
+	}
+	structValue = structValue.Elem()
+	for name, newValue := range newVals {
+		fieldVal := structValue.FieldByName(name)
+		if fieldVal.CanSet() {
+			fieldVal.Set(reflect.ValueOf(newValue))
+		} else if fieldVal.CanAddr() {
+			ptr := fieldVal.Addr()
+			if ptr.CanSet() {
+				ptr.Set(reflect.ValueOf(newValue))
+			} else {
+				Printfln("Can't set field via pointer: %v", name)
+			}
+		} else {
+			Printfln("Can't set field: %v", name)
+		}
+	}
+}
+
+func main27() {
+	Printfln("\nmain27:")
+
+	product := Product{Name: "Kayak", Category: "Watersports", Price: 279}
+	customer := Customer{Name: "Acme", City: "Chicago"}
+	Purchase := Purchase{Customer: customer, Product: product, Total: 279, taxRate: 10}
+	getFieldValues(Purchase)
+
+	Printfln("sets:")
+	setFieldValues(&Purchase, map[string]interface{}{
+		"City":     "London",
+		"Category": "Boats",
+		"Total":    100.50,
+	})
+	getFieldValues(Purchase)
+}

27-reflection/reflection/types.go

@@ -14,9 +14,20 @@ type Payment struct {
 	Amount   float64
 }
 
+type ProductPayment struct {
+	Payment `alias:"pay"`
+}
+
 type Purchase struct {
-	Product
 	Customer
+	Product
+	ProductPayment
 	Total   float64
 	taxRate float64
 }
+
+type Person struct {
+	Name    string `alias:"id"`
+	City    string `alias:""`
+	Country string
+}