我在 ArrayList 中有 10001 个元素,当我尝试将它们一一删除时,我在中途(即在 5000 个元素之后)收到 IndexOutOfBoundsException
异常。实在不知道为什么。
public static void main(String[] args) {
List<Integer> numberArrayList = new ArrayList<>();
List<Integer> numberLinkedList = new LinkedList<>();
long start, end;
start = System.currentTimeMillis();
for (int i = 0; i < 10_001; i++) {
numberArrayList.add(i);
}
end = System.currentTimeMillis();
System.out.println("Time taken to insert 10_001 elements in ArrayList: " + (end - start));
start = System.currentTimeMillis();
for (int i = 0; i < 10_001; i++) {
numberLinkedList.add(i);
}
end = System.currentTimeMillis();
System.out.println("Time taken to insert 10_001 elements in LinkedList: " + (end - start));
/* **************************************************************/
start = System.currentTimeMillis();
for (int i = 0; i < 10_001; i++) {
numberArrayList.remove(i);
}
end = System.currentTimeMillis();
System.out.println("Time taken to remove 10_001 elements from the front in ArrayList: " + (end - start));
start = System.currentTimeMillis();
for (int i = 0; i < 10_001; i++) {
numberLinkedList.remove(i);
}
end = System.currentTimeMillis();
System.out.println("Time taken to remove 10_001 elements from the front in LinkedList: " + (end - start));
}
上面的程序结果
Time taken to insert 100_001 elements in ArrayList: 2
Time taken to insert 100_001 elements in LinkedList: 1
Exception in thread "main" java.lang.IndexOutOfBoundsException: Index: 5001, Size: 5000
at java.util.ArrayList.rangeCheck(ArrayList.java:657)
at java.util.ArrayList.remove(ArrayList.java:496)
at collections_jnit.list.ArrayList_vs_LinkedList.main(ArrayList_vs_LinkedList.java:34)
最佳答案
一旦删除 5000 个元素,则意味着 10001-5000 = 5001,因此考虑从 0
开始索引,所以现在索引范围为 0
到 5000
因此 5001 是异常(exception)。
解决方案:如果您想在遍历时从列表中删除项目,那么我建议使用迭代器
Iterator<Integer> itr = numberArrayList.iterator();
while (itr.hasNext()) {
itr.remove();
}
关于java - IndexOutOfBoundsException 即使元素存在于数组列表中,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/49541358/