java - Java中根据子类Type定义父类方法的泛型Type

Question

是否可以根据子类Type动态识别T为返回类型？ 我想要如下内容:

public class Parent {
        public <T extends Parent> T foo() {
                return (T)this;
        }
}

public class Child extends Parent {
        public void childMethod() {
                System.out.println("childMethod called");
        }
}

然后调用:

Child child = new Child();
child.foo().childMethod();

没有像这样定义类型:

Child child = new Child();
child.foo().<Child>childMethod(); // compiles fine

提前致谢!

Answer 1

你想要这个:

public class Parent<T extends Parent<T>> {
    public T foo() {
        return (T)this;
    }
}

public class Child extends Parent<Child> {
    public void childMethod() {
        System.out.println("childMethod called");
    }
}

Child child = new Child();
child.foo().childMethod(); // compiles