学习scala笔记--15 trait 构造机制

 

 

 

 

 

trait 构造机制  

 

通过下面例子 看构造 执行顺序

 

scala> class Person {  println("--person--")}

defined class Person

 

scala> trait Logger { println("--Logger--")}

defined trait Logger

 

scala> trait ALogger extends Logger { println("--ALogger--")}

defined trait ALogger

 

scala> trait BLogger extends Logger { println("--BLogger--")}

defined trait BLogger

 

scala> class Student extends Person with ALogger with BLogger{

     | println(" --student--")

     | }

defined class Student

 

scala> var s = new Student

--person--

--Logger--

--ALogger--

--BLogger--

 --student--

s: Student = Student@411e5672

 

 

 

注意 with 后面的 trait 的顺序

 

scala> class Student2 extends Person with BLogger with ALogger {

     | println(" --student--") }

defined class Student2

 

scala> var s2 = new Student2

--person--

--Logger--

--BLogger--

--ALogger--

 --student--

s2: Student2 = Student2@ec50502