java - 您可以在 switch 语句的代码块中引用 case 值吗？

Question

那么你能在 Java 中做这样的事情吗:

Can you get the value being switched on inside a switch expression

我的代码中有很多这样的情况(为了清晰起见，删除了实际的逻辑代码):

    switch (weatherSystem.getRealClass().getSimpleName())
    {
        case "SyncWeatherSystem":
            logger.info("initializing sync weather system");
            …
            break;
        case "AsyncWeatherSystem":
            logger.info("initializing  async weather system");
            …       
            break;
        case "FixedWeatherSystem":
            logger.info("initializing fixed weather system");
            …
            break;
        case "NoWeatherSystem":
            logger.info("initializing no weather system");
            …
            break;
    }

我真的很想做:

    switch (weatherSystem.getRealClass().getSimpleName())
    {
        case "SyncWeatherSystem":
            logger.info("initializing {}", case.value);
            …
            break;
        case "AsyncWeatherSystem":
            logger.info("initializing {}", case.value); 
            …
            break;
        case "FixedWeatherSystem":
            logger.info("initializing {}", case.value);
            …
            break;
        case "NoWeatherSystem":
            logger.info("initializing {}", case.value);
            …
            break;
    }

这在 Java 中可能吗？

Answer 1

没有。它不是。但是，weatherSystem.getRealClass().getSimpleName() 是。我建议您将该值保存到局部变量中。您的所有案例似乎都在做同样的事情。因此，正如发布的那样，您可以简化它。喜欢

String sName = weatherSystem.getRealClass().getSimpleName();
switch (sName)
{
    case "SyncWeatherSystem":
    case "AsyncWeatherSystem":
    case "FixedWeatherSystem":
    case "NoWeatherSystem":
        logger.info("initializing {}", sName);
        break;
}