Groovy - 将属性从一个对象绑定到另一个对象 [英] Groovy - bind properties from one object to another

问题描述

有没有办法将属性从一个类的实例绑定到另一个类的实例的属性（两者之间的通用字段）。请看下面的例子：

  class One {
 String foo 
 String bar 
} 
 
 class Two {
 String foo 
 String bar 
 String baz 
} 
 
 def one = new One（foo：' one-foo'，bar：'one-bar'）
 def two = new Two（）
 
 two.properties = one.properties 
 
 assertone -foo== two.foo 
 assertone-bar== two.bar 
 assert！two.baz 
  

结果是一个错误：无法设置只读属性：类的属性：两个

解决方案

<问题是，对于每个对象， .properties 包含两个内置的 Groovy定义的属性，它们是 metaClass 和 class 。你想要做的只是设置用户定义的属性。您可以使用如下所示的代码轻松完成此操作：

  class One {
 String foo 
 String bar 
 
 
 class Two {
 String foo 
 String bar 
 String baz 
} 
 
 def one = new One（foo：'one-foo'，bar：'one-bar'）
 
 //您可能需要定义一个辅助方法，该方法对于任何Groovy都执行以下3行对象
 def propsMap = one.properties 
 propsMap.remove（'metaClass'）
 propsMap.remove（'class'）
 
 def two = new Two（propsMap ）
 
 assertone-foo== two.foo 
 assertone-bar== two.bar 
 assert！two.baz 
  




Is there a way to bind properties from one instance of a class to the properties of an instance of another class (the common fields between the two). See the example below:

class One {
  String foo
  String bar
}

class Two {
  String foo
  String bar
  String baz
}

def one = new One(foo:'one-foo', bar:'one-bar')
def two = new Two()

two.properties = one.properties

assert "one-foo" == two.foo
assert "one-bar" == two.bar
assert !two.baz

The result is an error: Cannot set readonly property: properties for class: Two

解决方案

The problem is that for every object, .properties includes two built-in Groovy-defined properties, these are the metaClass and class. What you want to do is only set the user-defined properties. You can easily do this using code such as that shown below:

class One {
  String foo
  String bar
}

class Two {
  String foo
  String bar
  String baz
}

def one = new One(foo:'one-foo', bar:'one-bar')

// You'll probably want to define a helper method that does the following 3 lines for any Groovy object
def propsMap = one.properties
propsMap.remove('metaClass')
propsMap.remove('class')

def two = new Two(propsMap)

assert "one-foo" == two.foo
assert "one-bar" == two.bar
assert !two.baz

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