java - 如何在方法接口中返回泛型类型

Question

如何为接口定义通用返回类型，以便它的实现类可以有自己的返回类型？

public interface A {
    public <T> T doSomething();     
}


public class ImplA implements A {
    public SomethingElseA doSomething() {
        return obj.doSomething();
    }
}

public class ImplB implements A {
    public SomethingElseB doSomething() {
        return obj.doSomething();
    }
}

Answer 1

尝试如下。

interface A<T> {

  T doSomething();
}

class ImplA implements A<SomethingElseA> {

  public SomethingElseA doSomething() {
    ...
  }
}

class ImplB implements A<SomethingElseB> {

  public SomethingElseB doSomething() {
    ...
  }
}

Answer 2

我猜你的意思是这样的？我将 do() 更改为 foo() 因为 do 是保留字...

public interface A<T> {
    public T foo();      
}

public class ImplA implements A<SomethingElseA> {
    @Override
    public SomethingElseA foo() {
        return obj.doSomething();
    }
}

public class ImplB implements A<SomethingElseB> {
    @Override
    public SomethingElseB foo() {
        return obj.doSomething();
    }
}