在java8中处理多个Null检查 [英] Multiple Null checks handling in java8

问题描述

在下面的情况下，我没有多次空检查，而是计划添加一些可读的代码。可以借助java 8流/地图。有人可以帮我这个吗

Instead of multiple null checks in below case, I am planning to add something readable code instead. May be with the help of java 8 streams/maps. Can somebody help me with this

private String getRailsServiceClass(IRailsComponent railsComponent) {
        String serviceClass = "";
        if (railsComponent != null && railsComponent.getRailOffer() != null && railsComponent.getRailOffer().getRailProducts().get(0).getRailProduct() != null && railsComponent.getRailOffer().getRailProducts().get(0).getRailProduct().getFareBreakdownList() != null &&
                railsComponent.getRailOffer().getRailProducts().get(0).getRailProduct().getFareBreakdownList().get(0).getPassengerFareList() != null && railsComponent.getRailOffer().getRailProducts().get(0).getRailProduct().getFareBreakdownList().get(0).getPassengerFareList().get(0).getPassengerSegmentFareList() != null &&
                railsComponent.getRailOffer().getRailProducts().get(0).getRailProduct().getFareBreakdownList().get(0).getPassengerFareList().get(0).getPassengerSegmentFareList().get(0).getCarrierServiceClassDisplayName() != null) {
            return railsComponent.getRailOffer().getRailProducts().get(0).getRailProduct().getFareBreakdownList().get(0).getPassengerFareList().get(0).getPassengerSegmentFareList().get(0).getCarrierServiceClassDisplayName();
        }
        return serviceClass;
    }

推荐答案

您可以使用Optional作为您的目的。

You can use Optional for your purpose.

String serviceClass = Optional.ofNullable(railsComponent)
           .map(IRailsComponent::getRailOffer)
           .map(RailOffer::getRailProducts)
           ...
           .orElse("");

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