没有内置的方法可以做到这一点.您当然可以编写一个方法，该方法将采用 Foo 并创建一个已使用相关属性初始化的 Bar.

There's no built-in way to do this. You can certainly write a method that will take a Foo and create a Bar that's been initialized with the relevant properties.

  public Bar getBar() {
       Bar bar = new Bar();
       bar.setPropOne(this.getPropOne());
       bar.setPropTwo(this.getPropTwo());
       return bar;
  }

另一方面，继承意味着Foo 是 Bar，所以你可以这样做

On the other hand, what inheritance means is that a Foo is a Bar, so you could just do

 public Bar getBar() {
      return this;
   }