Scala Play框架解析错误

Question

I have 2 foriegn key with same table and it parse into the program get a compilation error The problem is the 2 Id's are get null

Model Class MyFriend & functions

case class MyFriend(id: Pk[Long]= NotAssigned,user_Id:Option[Long],friend_Id:Option[Long],is_accepted:Boolean)
object MyFriend{
  /**
   * parse a Myfreind from a ResultSet.
   */
  val simple ={
    get[Pk[Long]]("myfriend.id") ~
    get[Option[Long]]("myfriend.user_Id")~
    get[Option[Long]]("myfriend.friend_Id")~
    get[Boolean]("myfriend.is_accepted") map{
      case id ~ user_Id ~ friend_Id ~ is_accepted => MyFriend(id, user_Id,friend_Id,is_accepted)
    }
   }


 /**
   * Parse a MyFriend from a userProfile
   */
  val withUserProfile =MyFriend.simple ~ (UserProfile.simple ?) map{
    case myfriend  ~ userprofile => (myfriend, userprofile)
  }
  /**
   * create a new MyFriend.
   *
   * @param myfriend 
   */
  def insert(myFriend: MyFriend): Long = {
    DB.withConnection { implicit connection =>
      SQL(
        """
          insert into MY_FRIEND(USER_ID,FRIEND_ID,IS_ACCEPTED) values (
            {user_Id}, {friend_Id},{is_accepted}
          )
        """).on(
          'user_Id -> myFriend.user_Id,
          'friend_Id -> myFriend.friend_Id,
          'is_accepted -> myFriend.is_accepted
          ).executeUpdate()
    }
  }


/**
   * Update a MyFriend
   *
   * @param  MyFriend
   */
  def update(myFriend:MyFriend)={
  DB.withConnection{ implicit connection =>
    SQL(
        """
        update MY_FRIEND
        set FRIEND_ID = {friend_Id}, IS_ACCEPTED={is_accepted} where USER_ID={use_id}
        """).on(
          'user_Id -> myFriend.user_Id,
          'friend_Id -> myFriend.friend_Id,
          'is_accepted -> myFriend.is_accepted
          ).executeUpdate()

  }

}
/**
   * Find myfriendId Via userprofile
   */
  def authenticate(myFriend: MyFriend) = {
    DB.withConnection { implicit connection =>
      val myFriendFound = SQL(
        """
          select * from MY_FRIEND 
          where USER_ID = {user_Id} and FRIEND_ID={friend_Id}
        """).on(
          'user_Id -> myFriend.user_Id,
          'friend_Id ->myFriend.friend_Id
          ).as(MyFriend.simple.singleOpt)
      myFriendFound
    }
  }

Model UserProfile amd Functions

case class UserProfile(id: Pk[Long] = NotAssigned, useraccountid: Option[Long], name: String, date_of_birth: Date, gender: String, image: String,status:String)

object UserProfile{

  /**
   * Parse a UserProfile from a ResultSet
   */
  val simple = {
    get[Pk[Long]]("user_profile.id") ~
      get[Option[Long]]("user_profile.user_account_id") ~
      get[String]("user_profile.name") ~
      get[Date]("user_profile.date_of_birth") ~
      get[String]("user_profile.gender") ~
      get[String]("user_profile.image") ~
      get[String]("user_profile.status") map {
        case id ~ user_account_id ~ name ~ date_of_birth ~ gender ~ image ~ status =>
          UserProfile(id, user_account_id, name, date_of_birth, gender, image,status )
      }
  }
 /**
   * Parse a userProfile from a MyFriend
   */
  val withMyFriend =UserProfile.simple ~ (MyFriend.simple ?) map{
    case userprofile  ~ myfriend  => (userprofile, myfriend)
  }
/**
   * Find MyFriend With MyFriend Detail
   */

  def myFriend(user_Id:Long) = {
    DB.withConnection { implicit connection =>
      val myFriend = SQL(
        """
          select * from MY_FRIEND
          where USER_ID = {user_id}
        """).on(
          'user_Id -> user_Id).as(MyFriend.simple.singleOpt)
      myFriend
    }
  }
  /**
   * Authonticate
   */
  def authenticate(userprofile: UserProfile) = {
    DB.withConnection { implicit connection =>
      val userProfileFound = SQL(
        """
          select * from USER_PROFILE 
          where ID = (id}
        """).on(
          'Id -> userprofile.id
          ).as(UserProfile.simple.singleOpt)
      userProfileFound
    }
  }

Controller Application method for parse friend and user Id

val userprofile:UserProfile=null
        val myfriend:MyFriend=null

   def authenticateFriend = Action { implicit request =>
            val alert: Alert = new Alert("", "")
            Common.setAlert(alert)
            myFriendForm.bindFromRequest.fold(
            errors => BadRequest(views.html.myFriend(errors,userprofile,myfriend)),
        myFriend => {
            val myfriendOpt = MyFriend.authenticate(myFriend)
        myfriendOpt match {

       case Some(authmyfriend: MyFriend) =>
            val userSession = request.session + ("myFriendId" -> authmyfriend.id.toString)
            val friendSession=request.session + ("userProfileId" -> userprofile.id.toString)
            val myFriendOpt = MyFriend.userProfile(authmyfriend.id.get)
       myFriendOpt match {
       case None => Ok(views.html.myFriend(Application.myFriendForm, userprofile,myfriend)).withSession(userSession)
       case Some(userProfileFound: UserProfile) =>
            val myFriendFormWithDetails = Application.myFriendForm.fill(userProfileFound)
            Ok(views.html.myFriend(myFriendFormWithDetails,userprofile,authmyfriend)).withSession(userSession)

            }

          }
      })

  }

Create MyFriend Page function

     def createMyFriend = Action { implicit request =>
   if (request.session.get("userId") == None) {
      Results.Redirect("/")
    }
   else {
        val myfriends:MyFriend=null
        val userprofileId = request.session.get("myFriendId").get.toLong//userProfileId
        val userprofile = UserProfile.findUserByAccountId(userprofileId).get
        println(userprofile)
        val myfriendId = request.session.get("userProfileId").get.toLong//myFriendId
        val myfriend = MyFriend.friendidByUserIsAccepted(myfriendId,true)
        println(myfriend)
        myFriendForm.bindFromRequest.fold(
        errors => BadRequest(views.html.myFriend(errors, userprofile,myfriends)),
   myFriend => {
          println("errors")
          val myFriendOpt = UserProfile.myFriend(userprofile.id.get)
          println(myFriendOpt)
   myFriendOpt match {
   case None =>
          val updatedMyFriend = MyFriend(NotAssigned,
          Option(userprofileId), Option(myfriendId),myFriend.is_accepted)
          MyFriend.insert(updatedMyFriend)
          val alert: Alert = new Alert("success", " MyFriend Saved")
          Common.setAlert(alert)
          }
          Results.Redirect("/myFriend")
        })  
        }
    }        

Redirect To myFriend page

def myFriend = Action { implicit request =>

   Ok(views.html.myFriend(Application.myFriendForm,userprofile,myfriend))
    }

Whenrun the program get nullpointer for id's

I am stuck with this problem with couple of days if any one had the same problem and anyone is solved

Answer 1

Just add to your pattern matching construct.

case None => // do some if None 

or

case _ => // something in this case

or you can simply ignore this case by omiting right hand side of the arrow

The problem is that you didn't cover all the posible cases in you function. You've covered Some (authuserProfile:UserProfile) and case Some(authmyfriend: MyFriend) , but not None case and it looks like your method receives None.

Updated

The error occurres because you have _ which matches all cases, so you pattern matching construct just can't reach anything (Some in your case) after case _ => //...

If i understood your code correct, the problem is in this part

userProfileOpt match {
  case _ => Ok(views.html.myFriend(...).withSession(friendSession)
  case _ =>
    val myFriendFound: UserProfile=null
    val useracc:UserAccount=null

Both cases mathes all posible cases, that's an error

Answer 2

UserProfile.myFriend returns MyFriend , not Option[MyFriend] . Therefore, your pattern match is incorrect. You can try to fix the def myFriend to return Option , or remove the pattern match.

(edit): Probably you should change from MyFriend.simple.single to MyFriend.simple.singleOpt .

As a rule of thumb, always use an explicit return type from public methods. Type inference is very powerful and useful, but use it wisely.