Java 泛型类型转换，例如 <String, String> 到 <Object, Object>

Question

java有没有办法转换类型

来自 : <Object, Object>

至：<String, String>

或

来自 : <String, String>

至：<Object, Object>

我在 ConcurrentKafkaListenerContainerFactory<Object, Object> 和 ConcurrentKafkaListenerContainerFactory<String, String>

之间

Answer 1

您必须使用中间原始类型。这是 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并且 ClassCastException 将在运行时发生，如果这些工厂将使用不同的类型。

Java 泛型类型转换，例如 <String, String> 到 <Object, Object>

Java generic type conversion like <String, String> to <Object, Object>

java

spring-boot

spring-kafka