如何将arrayList存储到java中的数组中？

How to store arrayList into an array in java?

如何将arrayList存储到java中的数组中？

7 个解决方案

#1

That depends on what you want:

这取决于你想要的：

List<String> list = new ArrayList<String>();
// add items to the list

Now if you want to store the list in an array, you can do one of these:

现在，如果要将列表存储在数组中，可以执行以下操作之一：

Object[] arrOfObjects = new Object[]{list};
List<?>[] arrOfLists = new List<?>[]{list};

But if you want the list items in an array, do one of these:

但是，如果您想要数组中的列表项，请执行以下操作之一：

Object[] arrayOfObjects = list.toArray();
String[] arrayOfStrings = list.toArray(new String[list.size()]);

Reference:

参考：

• Collection.toArray()
• Collection.toArray（）
• Collection.toArray(T[])
• Collection.toArray（T []）

#2

If Type is known (aka not a generics parameter) and you want an Array of Type:

如果Type已知（也就是非泛型参数）并且您想要一个Type类型：

ArrayList<Type> list = ...;
Type[] arr = list.toArray(new Type[list.size()]);

Otherwise

除此以外

Object[] arr = list.toArray();

#3

You mean you want to convert an ArrayList to an array?

你的意思是你想将ArrayList转换为数组？

Object[] array = new Object[list.size()];
array = list.toArray(array);

Choose the appropriate class.

选择合适的班级。

#4

List list = getList();
Object[] array = new Object[list.size()];
for (int i = 0; i < list.size(); i++)
{
  array[i] = list.get(i);
}

Or just use List#toArray()

或者只使用List＃toArray（）

#5

List<Foo> fooList = new ArrayList<Foo>();
Foo[] fooArray = fooList.toArray(new Foo[0]);

#6

List list = new ArrayList();

list.add("Blobbo");

list.add("Cracked");

list.add("Dumbo");

// Convert a collection to Object[], which can store objects    

Object[] ol = list.toArray();

#7

Try the generic method List.toArray():

尝试通用方法List.toArray（）：

List<String> list = Arrays.asList("Foo", "Bar", "Gah");
String array[] = list.toArray(new String[list.size()]);
// array = ["Foo", "Bar", "Gah"]