java - 实例化参数化类

Question

只是想知道这样做是否正确。我想构造我的参数化类的实例，其中一个实例变量是泛型类型。下面的代码有效，但我在主要方法中收到很多警告“SomeObject 是原始类型。对泛型类型 SomeObject 的引用应该被参数化”。

public class SomeObject<T> {

    private String description;

    private T value;


    public SomeObject(String description, T value) {
        this.description = description;
        this.value = value;
    }



public static void main(String args[]){

    List <SomeObject> objectList = new ArrayList<SomeObject>();

    objectList.add(new SomeObject("Object 1: ", true));
    objectList.add(new SomeObject("Object 2: ", 888.00));
    objectList.add(new SomeObject("Object 3: ", "another object"));
    objectList.add(new SomeObject("Object 4: ", '4'));

    for (SomeObject object : objectList){
    System.out.println(object.getDescription() + object.getValue());
    }
}

Answer 1

The code below works but I get a lot of warnings in the main method "Object is a raw type. References to generic type Object should be parameterized".

警告是因为您在构造 SomeObject 时没有指定类型参数。即。

应该是:

List<SomeObject<?>> objectList = new ArrayList<>();
objectList.add(new SomeObject<Boolean>("Object 1: ", true));
objectList.add(new SomeObject<Double>("Object 2: ", 888.00));
objectList.add(new SomeObject<String>("Object 3: ", "another object"));
objectList.add(new SomeObject<Character>("Object 4: ", '4'));