Java形式类型参数定义(泛型)

public class MyGenericClass<T> {
    private T data;

    public void setData(T data) {
        this.data = data;
    }

    public T getData() {
        return data;
    }
}

MyGenericClass<String> stringClass = new MyGenericClass<>();
stringClass.setData("Hello, world!");
System.out.println(stringClass.getData()); // 输出 "Hello, world!"

MyGenericClass<Integer> integerClass = new MyGenericClass<>();
integerClass.setData(123);
System.out.println(integerClass.getData()); // 输出 123

List<String> stringList = new ArrayList<String>();
stringList.add("Hello, world!");
String s = stringList.get(0); // 正确

List<Integer> integerList = new ArrayList<Integer>();
integerList.add(123);
String s2 = integerList.get(0); // 错误，无法将Integer转换为String