JAVA 与C#构造函数执行顺序的不同之处.

领测软件测试网 JAVA: 先执行父类的构造函数，然后是引用对象的构造函数（必须有new声明实际类型）,然后是自己的构造函数。
public class Test
{
public static void main(String[] args)
{
Child child = new Child();
}
}

class Parent
{
Parent()
{
System.out.println("to construct Parent.");
}
}

class Child extends Parent
{
Child()
{
System.out.println("to construct Child.");
}
Delegatee delegatee = new Delegatee();
}


class Delegatee
{
Delegatee()
{
System.out.println("to construct Delegatee.");
}
}


结果是

而C#的构造函数执行顺序是:先引用对象，在父类，再子类.to construct Parent.
to construct Delegatee.
to construct Child.

using System;

namespace ConsoleApplication1
{
public class Test
{
public static void Main(String[] args)
{
Child child = new Child();
}
}

class Parent
{
public Parent()
{
Console.WriteLine("to construct parent");
}
}

class Child : Parent
{
public Child()
{
Console.WriteLine("to construct Child.");
}
Delegatee delegatee = new Delegatee();
}
class Delegatee
{
public Delegatee()
{
Console.WriteLine("to construct Delegatee.");
}
}
}

结果是
to construct Delegatee.
to construct Child.
to construct Parent.


总结：
被依赖的先构造，依赖于人的后构造。JAVA 是跨层依赖优先于同层依
赖构造，而C#是同层依赖优先于跨层依赖.

文章来源于领测软件测试网 https://www.ltesting.net/