java - 创建一个在类之间共享其属性的对象

Question

我想创建一个A类的对象，并在B类、C类和D类中初始化它

该对象应该被共享；也就是说，如果对这些类(C 和 D)中的 objA 进行任何更改，即使在 objC、'objD' 被销毁之后，其内容仍然保持不变，假设 B 类 是主类。我想使用它的属性是class B

class A {}

class B
{
  initialize class A object and use-change its property
  initialize class C object and use-change its property
  initialize class D object and use-change its property
}

class C{initialize class A object and use-change its property}

class D{initialize class A object and use-change its property}

class X{initialize B and destroy objC,objD, from objB use property of objA of class B}

Answer 1

非静态尝试如下所示:

您的目标对象:

public class A {

}

您的类，对对象执行某些操作:

public class C {
    private final A a;

    public C(final A a) {
        this.a = a;
    }

    public foo() {
        // do something with a
    }
}

public class D {
    private final A a;

    public D(final A a) {
        this.a = a;
    }

    public otherFoo() {
        // do something with a
    }
}

您的主类(class):

public class B {

    public static void main(String[] args) {
        final A a = new A();

        final C c = new C(a);
        final D d = new D(a);


        c.foo();
        d.otherFoo();
    }
}