在for-each循环迭代开始之前，有没有办法避免空检查？ [英] Is there a way to avoid null check before the for-each loop iteration starts?

问题描述

每次我必须迭代一个集合，最终在for-each循环迭代开始之前检查null。像这样：

pre $ if（list1！= null）{
for（Object obj：list1）{





$ b $ p $是有一个更短的方法，所以我们可以避免写如果块？
注意：我正在使用Java 5，并且会一直使用它。

解决方案

答案是：没有办法把它缩短。有一些技术，如评论中的，但我没有看到自己使用它们。我认为写一个if块比使用这些技术更好。是的..在任何人再次提到它之前:)理想情况下的代码应该被设置，这样的列表不应该是一个空

Every time I have to iterate over a collection I end up checking for null, just before the iteration of the for-each loop starts. Like this:

if( list1 != null ){
    for(Object obj : list1){

    }
}

Is there a shorter way, so that we can avoid writing the "if" block ? Note: I am using Java 5, and will be stuck with it for sometime.

解决方案

I guess the right answer is that: there is no way to make it shorter. There are some techniques such as the ones in the comments, but I don't see myself using them. I think it's better to write a "if" block than to use those techniques. and yes.. before anybody mentions it yet again :) "ideally" the code should be desgined such that list should never be a null

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