Groovy中的方法重写

Question

在Groovy中，如何在扩展超类的类中重写超类中的方法？Java方式不起作用，因为两个方法(超类中的方法和子类中的方法)都在执行。例如：

class SuperClass {

  SuperClass(){

    println("This is the superclass")
  }

  def awaitServer(){
    println("awaiting server in the superclass")
  }

}


class SubClass extends SuperClass{


  SubClass(){
    println("This is the subclass")
  }

  @Override
  def awaitServer(){
    println("awaiting server in the subclass")
  }

}

//////
SubClass sb = new SubClass()
sb.awaitServer()

我得到的输出是：

awaiting server in the superclass
awaiting server in the subclass

正如您所看到的，当我在子类中重写超类的方法时，这两个方法都会执行。为什么会发生这种情况？Groovy中的方法重写是如何实现的？

我已经在网上搜索过了，但我还是找不到。谁能提供一个样本或一个简单的例子？

先谢谢你，

Answer 1

您忘记添加def。下面的代码可以正常工作：

class SuperClass {
   SuperClass(){
      println("This is the superclass")
   }

   def awaitServer() {
      println("awaiting server in the superclass")
   }
}

class SubClass extends SuperClass{

   SubClass() {
      println("This is the subclass")
   }

   @Override
   def awaitServer() {
      println("awaiting server in the subclass")
   }
}

SubClass sb = new SubClass()
sb.awaitServer()

它输出：

This is the superclass 
This is the subclass 
awaiting server in the subclass

看看下面的输出：

[opal@opal-mac-2]/tmp % cat lol.groovy 
class SuperClass {
   SuperClass(){
      println("This is the superclass")
   }

   def awaitServer() {
      println("awaiting server in the superclass")
   }
}

class SubClass extends SuperClass{

   SubClass() {
      println("This is the subclass")
   }

   @Override
   def awaitServer() {
      println("awaiting server in the subclass")
   }
}

SubClass sb = new SubClass()
sb.awaitServer()

[opal@opal-mac-2]/tmp % groovy -v
Groovy Version: 2.4.0 JVM: 1.8.0_05 Vendor: Oracle Corporation OS: Mac OS X
[opal@opal-mac-2]/tmp % groovy lol.groovy 
This is the superclass
This is the subclass
awaiting server in the subclass

在groovy 1.8.6中：

[opal@opal-mac-2]/tmp % gvm use groovy 1.8.6
==== BROADCAST =================================================================
* 27/02/15: Springboot 1.1.11.RELEASE has been released on GVM. #spring
* 27/02/15: Springboot 1.2.2.RELEASE has been released on GVM. #spring
* 26/02/15: Grails 3.0.0.M2 has been released on GVM. #grailsframework
================================================================================

Stop! groovy 1.8.6 is not installed.
Do you want to install it now? (Y/n): Y

Downloading: groovy 1.8.6

  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0
100 15.5M  100 15.5M    0     0  2666k      0  0:00:05  0:00:05 --:--:-- 3716k

Installing: groovy 1.8.6
/Users/opal/.gvm/tmp/groovy-1.8.6 -> /Users/opal/.gvm/groovy/1.8.6
Done installing!


Using groovy version 1.8.6 in this shell.
[opal@opal-mac-2]/tmp % groovy lol.groovy 
This is the superclass
This is the subclass
awaiting server in the subclass