优化类型的定义

to_int.go

@@ -8,33 +8,40 @@ import (
 // interface 转 int
 func ToInt(val interface{}) (i int, err error) {
 
-	if v, ok := val.(string); ok {
-		// 不支持小数转换
-		i, err = strconv.Atoi(v)
-	} else if v, ok := val.(float32); ok {
-		i = int(v)
-	} else if v, ok := val.(float64); ok {
-		i = int(v)
-	} else if v, ok := val.(int); ok {
-		i = v
-	} else if v, ok := val.(int32); ok {
-		i = int(v)
-	} else if v, ok := val.(int64); ok {
-		i = int(v)
-	} else if v, ok := val.(uint); ok {
-		i = int(v)
-	} else if v, ok := val.(uint32); ok {
-		i = int(v)
-	} else if v, ok := val.(uint64); ok {
-		i = int(v)
-	} else if v, ok := val.(bool); ok {
+	switch v := val.(type) {
+	case nil:
+		return 0, nil
+	case string:
+		return strconv.Atoi(v)
+	case float32:
+		return int(v), nil
+	case float64:
+		return int(v), nil
+	case int:
+		return v, nil
+	case int8:
+		return int(v), nil
+	case int16:
+		return int(v), nil
+	case int32:
+		return int(v), nil
+	case int64:
+		return int(v), nil
+	case uint:
+		return int(v), nil
+	case uint8:
+		return int(v), nil
+	case uint32:
+		return int(v), nil
+	case uint64:
+		return int(v), nil
+	case bool:
 		if v {
-			i = 1
+			return 1, nil
 		} else {
-			i = 0
+			return 0, nil
 		}
-	} else {
-		return 0, errors.New("类型转换失败")
 	}
-	return
+
+	return 0, errors.New("can not convert to int")
 }