如何从作为 lambda 传递的函数接口对象实例获取参数？

Question

@FunctionalInterface
public interface ServiceCaller {
    void callService();
}

//common method to execute any service call
public void executeService(ServiceCaller serviceCaller) {
    //do common things
    //i want to access dbValidationRequest/apiValidationRequest here for logging purpose
    try {
        serviceCaller.callService();
    } catch (Exception ex) {
        //do common things
        LogUtils.log(logger, ex);
    }
    //do common things
}

//my clients call this
public void validateFromDb(DbValidationRequest dbValidationRequest){
    commonUtils.executeService(()-> dbValidationService.validate(dbValidationRequest));
}

//my clients call this
public void validateFromApi(ApiValidationRequest apiValidationRequest){
    commonUtils.executeService(()-> apiValidationService.validate(apiValidationRequest));
}

这是Java Spring应用程序的控制器。在executeService方法中，我传递了ServiceCaller接口的一个实例。我使用此方法从控制器调用所有服务。如果我使用 intelliJ IDEA 进行评估，那么我可以在executeService 方法中查看 dbValidationRequest/apiValidationRequest 的值（如 arg$2，请参阅附图）。我需要打印这些对象以用于记录目的，我也根本不想使用方面。我怎样才能做到这一点。如果 intelliJ IDEA 可以看到这些值，为什么我不能以编程方式看到这些值？

Answer 1

arg$1可以arg$2将其视为类的字段，因此可以通过反射来获取它们。

    String var1 = "Content Var 1";
    String var2 = "Content Var 2";

    Supplier<String> stringSupplier = () -> var1 + var2;

    Field[] declaredFields = stringSupplier.getClass().getDeclaredFields();

    for (Field f : declaredFields) {
        f.setAccessible(true);
        System.out.println(
            "Field Name: " + f.getName() +
            ", value: " + f.get(stringSupplier)
        );
    }

    // Field Name: arg$1, value: Content Var 1
    // Field Name: arg$2, value: Content Var 2