java中构造函数返回值的用途是什么以及如何访问此值？(What is the use of constructor return value in java and how to access th

java中构造函数返回值的用途是什么以及如何访问此值？(What is the use of constructor return value in java and how to access this value?)

由于JDK 8允许返回类型的构造函数，并且还允许从构造函数返回一个值，因此它的用途是什么？ 如何在下面的程序中访问构造函数的返回值？

public class ConstructorReturn { int ConstructorReturn() { return 10; } public static void main(String... args) { ConstructorReturn constructorReturn = new ConstructorReturn(); } }

As JDK 8 allows return type of constructor and also allows to return a value from constructor so what is the use of it? How to access return value of constructor in below program?

public class ConstructorReturn { int ConstructorReturn() { return 10; } public static void main(String... args) { ConstructorReturn constructorReturn = new ConstructorReturn(); } }

最满意答案

int ConstructorReturn() { return 10; }

那不是构造函数。 这是一个与类同名的常规方法。 构造函数没有返回值。

构造函数永远不会有返回值（甚至无效）：

ConstructorReturn() { }

你的ConstructorReturn constructorReturn=new ConstructorReturn(); line不会调用您的ConstructorReturn方法。 它调用由编译器生成的默认无参数构造函数，因为您的类没有任何显式构造函数。

int ConstructorReturn() { return 10; }

That's not a constructor. It's a regular method having the same name as the class. A constructor has no return value.

A constructor will never have a return value (not even void) :

ConstructorReturn() { }

Your ConstructorReturn constructorReturn=new ConstructorReturn(); line doesn't invoke your ConstructorReturn method. It invokes the a default parameterless constructor that was generated by the compiler, since your class didn't have any explicit constructors.