在Stream中过滤Null项 [英] Filter Null items in Stream
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问题描述
使用Java Stream时,映射后有时会出现空值。目前,当需要省略这些值时,我使用:
When using a Java Stream, sometimes null values can occur after mapping. Currently when these values need to be omitted, I use:
.stream()
.<other operations...>
.filter(element -> element != null)
.<other operations...>
对于更实用的风格,可以快速编写一个小辅助方法:
For a more functional style a tiny helper method is quickly written:
public static <T> boolean nonNull(T entity) {
return entity != null;
}
因此您可以使用方法参考:
So that you can use a method reference instead:
.stream()
.<other operations...>
.filter(Elements::nonNull)
.<other operations...>
我找不到这样的jdk方法,即使我怀疑他们已经包含了一个。这里有不同的方法吗?或者他们是否因为某种原因而忽略了这一点?
I could not find such a jdk method, even though I would suspect they have included one. Is there a different approach here? Or did they omit this for a reason?
推荐答案
You can use Objects::nonNull from the Java8 SDK:
.stream()
.<other operations...>
.filter(Objects::nonNull)
.<other operations...>
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