我使用slick2.0和postgresql数据库：
我的数据模型是：
class User(tag: Tag) extends Table[(Int, String,String, String,Date,String,Long, Int)](tag, "User") {
def id = column[Int]("ID", O.PrimaryKey)
def first_name = column[String]("First_Name")
def second_name=column[String]("Second_Name")
def email=column[String]("Email")
def datebirth=column[Date]("Birth_date")
def password=column[String]("Password")
def addID = column[Long]("ADRESS")
// def shopID =column[Int]("Shop")
def privilege=column[Int]("privilege")
def * = (id, first_name, second_name, email, datebirth, password, addID, privilege)
// def home_address=foreignKey("ha_FK", addID, address)(_.id)
// def link_shop=foreignKey("sh_FK", shopID, shop)(_.id)
}
val user=TableQuery[User]
在我的Global.scala上：
(user.ddl).create -----line 67
错误是：
play.api.UnexpectedException: Unexpected exception[NullPointerException: null]
at play.core.ReloadableApplication$$anonfun$get$1$$anonfun$apply$1$$anon
fun$1.apply(ApplicationProvider.scala:148) ~[play_2.10-2.2.1.jar:2.2.1]
at play.core.ReloadableApplication$$anonfun$get$1$$anonfun$apply$1$$anon
fun$1.apply(ApplicationProvider.scala:112) ~[play_2.10-2.2.1.jar:2.2.1]
at scala.Option.map(Option.scala:145) ~[scala-library-2.10.3.jar:na]
at play.core.ReloadableApplication$$anonfun$get$1$$anonfun$apply$1.apply
(ApplicationProvider.scala:112) ~[play_2.10-2.2.1.jar:2.2.1]
at play.core.ReloadableApplication$$anonfun$get$1$$anonfun$apply$1.apply
(ApplicationProvider.scala:110) ~[play_2.10-2.2.1.jar:2.2.1]
at scala.util.Success.flatMap(Try.scala:200) ~[scala-library-2.10.3.jar:
na]
Caused by: java.lang.NullPointerException: null
at scala.slick.profile.RelationalProfile$TableQueryExtensionMethods.ddl(
RelationalProfile.scala:41) ~[slick_2.10-2.0.1.jar:2.0.1]
at InitialData$$anonfun$insert$1.apply(Global.scala:67) ~[na:na] ------------here is the user.dll.create and here is the error.
at InitialData$$anonfun$insert$1.apply(Global.scala:61) ~[na:na]
at scala.slick.backend.DatabaseComponent$DatabaseDef$class.withSession(D
atabaseComponent.scala:31) ~[slick_2.10-2.0.1.jar:2.0.1]
at scala.slick.jdbc.PlayDatabase.withSession(PlayDatabase.scala:6) ~[pla
y-slick_2.10-0.6.0.1.jar:2.0.1]
at InitialData$.insert(Global.scala:60) ~[na:na]
为什么当我创建数据表错误时，会出现NullPointerException
最佳答案
如果将TableQuery声明从以下位置更改，这似乎是初始化顺序问题：
val user=TableQuery[User]
至：
def user=TableQuery[User]
这样可以解决问题。
关于scala - 从数据模型创建数据表时，出现NullPointerException，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/22937541/