ArrayList循环遍历并删除元素的常见陷阱

Bertha 。 2023-10-14 11:53 140阅读 0赞

**出现的问题：**

如果在使用 for 循环遍历 ArrayList 时删除其中的元素，会抛出 ConcurrentModificationException 异常。

这是因为删除一个元素后，后面的元素会向前移动，但for循环的指针会继续向前移动一个，所以会导致有元素删除不到。

**解决方法：**

1.可以使用Iterator迭代器遍历删除。

2.也可以用for循环，从后往前遍历元素并删除元素，这样就不会导致部分元素遍历不到的问题。

>  **代码参考：**  [ ArrayList循环遍历并删除元素的常见陷阱 ][ArrayList_]
> 
> [ Java ArrayList遍历删除问题 ][Java ArrayList_]

[ArrayList_]: https://www.oschina.net/action/GoToLink?url=https%3A%2F%2Fwww.cnblogs.com%2Fhuangjinyong%2Fp%2F9455163.html
[Java ArrayList_]: https://www.oschina.net/action/GoToLink?url=https%3A%2F%2Fblog.csdn.net%2Fqq_42687916%2Farticle%2Fdetails%2F89528778%23%3A~%3Atext%3D%25E4%25B8%2580%25EF%25BC%258CArrayList%25E9%2581%258D%25E5%258E%2586%25E5%2588%25A0%25E9%2599%25A4%25E9%2597%25AE%25E9%25A2%2598%25201%25201.foreach%25E9%2581%258D%25E5%258E%2586%25E5%2588%25A0%25E9%2599%25A4%25EF%25BC%258C%25E6%258A%259B%25E5%25BC%2582%25E5%25B8%25B8%25202%25202.for%25E6%25AD%25A3%25E5%25BA%258F%25E9%2581%258D%25E5%258E%2586%25EF%25BC%258C%25E4%25BC%259A%25E6%2597%25A0%25E6%25B3%2595%25E5%2588%25A0%25E9%2599%25A4%25E6%25BB%25A1%25E8%25B6%25B3%25E6%259D%25A1%25E4%25BB%25B6%25E7%259A%2584%25E5%2585%2583%25E7%25B4%25A0%2C3%25203.Iterator%25E8%25BF%25AD%25E4%25BB%25A3%25E5%2599%25A8%2520%2528%25E8%25A7%25A3%25E5%2586%25B3%25E5%258A%259E%25E6%25B3%2595%25E4%25B8%2580%2529%25204%25204.for%25E5%2580%2592%25E5%25BA%258F%25E9%2581%258D%25E5%258E%2586%25E5%2588%25A0%25E9%2599%25A4%2520%2528%25E6%258E%25A8%25E8%258D%2590%25E8%25A7%25A3%25E5%2586%25B3%25E5%258A%259E%25E6%25B3%2595%25E4%25BA%258C%2529