什么传递给Arrays实例方法toArray（T [] a）方法？

问题描述

如果您有集合的实例，请说：

If you have an instance of a Collection, say something like:

Collection<String> addresses = new ArrayList<String>();

然后填充一堆值，这是最好的方式，if

Which were to then be populated with a bunch of values, which is the "best" way, if any, to make use of the toArray() method without requiring a type cast?

String[] addressesArray = addresses.toArray(new String[] {});
String[] addressesArray = addresses.toArray(new String[0]);
String[] addressesArray = addresses.toArray(new String[addresses.size()]);
String[] addressesArray = addresses.toArray(new String[addresses.size() + 5]);

前两者之间有语义上的区别吗？是第三最有效吗？是第四个比第三个效率低吗？

Is there any semantic difference between the first two? Is the third most efficient? Is the fourth less efficient than the third?

推荐答案

根据，这是最有效的：

String[] addressesArray = addresses.toArray(new String[addresses.size()]);

我相信他们;）

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