Java 泛型类型转换，如 到

Question

java中有没有一种方法来转换类型

来自:<Object, Object>

至:<String, String>

或

来自:<String, String>

至:<Object, Object>

 

我在ConcurrentKafkaListenerContainerFactory<Object, Object>之间有它和ConcurrentKafkaListenerContainerFactory<String, String>

Answer 1

您必须使用中间原始类型。以下是 Object 到 String 转换的示例。反向转换看起来是一样的。

static ConcurrentKafkaListenerContainerFactory<Object, Object> stringFactoryToObjectFactory(
        ConcurrentKafkaListenerContainerFactory<String, String> stringFactory) {
    @SuppressWarnings("rawtypes")
    ConcurrentKafkaListenerContainerFactory rawTypeFactory = stringFactory;
    @SuppressWarnings("unchecked")
    ConcurrentKafkaListenerContainerFactory<Object, Object> objectFactory = rawTypeFactory;
    return objectFactory;
}

当然，它违反了类型安全，如果这些工厂使用不同的类型，ClassCastException 将在运行时发生。