以下是Play应用程序的常规项目布局:
myProject
+ app
+ controllers
+ models
+ views
我认为大部分人都清楚 controllers
, models
和 views
的内容。现在假设我们需要使用蛋糕模式实现 DAO 服务:
DaoServiceComponent.scala
:
trait DaoServiceComponent[A] {
def daoService: DaoService
trait DaoService {
def insert(entity: A): Future[A]
def find(id: Id): Future[Option[A]]
...
}
}
trait DefaultDaoServiceComponent[A] extends DaoServiceComponent[A] {
this: DaoComponent[A] =>
def daoService = new DaoService {
def insert(entity: A) = dao.insert(entity)
def find(id: Id) = dao.find(id)
...
}
}
DaoComponent.scala
:
trait DaoComponent[A] {
def dao: Dao
trait Dao {
def insert(entity: A): Future[A]
def find(id: Id): Future[Option[A]]
...
}
}
UserDaoComponent.scala
:
trait UserDaoComponent extends DaoComponent[User] {
protected val collection: JSONCollection
def dao = new Dao {
def insert(entity: User): Future[User] = {
...
}
def find(id: Id): Future[Option[User]] = {
...
}
}
}
最后,我们像往常一样在控制器对象中进行所有的连接:
object Users extends Controller {
private val userService: DaoServiceComponent[User]#DaoService =
new DefaultDaoServiceComponent[User]
with UserDaoComponent {
val collection = db.collection[JSONCollection]("users")
}.daoService
def create = Action.async(parse.json) { implicit request =>
request.body.validate[User].fold(
valid = { user =>
userService.insert()..
...
}
}
现在回到我们的项目布局,我们应该把DaoServiceComponent
、DaoComponent
、UserDaoComponent
以及其他支持类放在哪里?这些文件应该一起放在services
目录中吗?
myProject
+ app
+ controllers
+ models
+ services
+ DaoComponent.scala
+ DaoException.scala
+ DaoServiceComponent.scala
+ EmailServiceComponent.scala
+ RichEmailComponent.scala
+ ServiceException.scala
+ UserDaoComponent.scala
+ ...
+ views