如何将arrayList存储到java中的数组中?
如何将arrayList存储到java中的数组中?
这取决于你想要的:
List list = new ArrayList (); // add items to the list
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};
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()]);
参考:
-
Collection.toArray()
-
Collection.toArray(T[])
如果Type已知(也就是非generics参数)并且您想要一个Type类型:
ArrayList list = ...; Type[] arr = list.toArray(new Type[list.size()]);
除此以外
Object[] arr = list.toArray();
你的意思是你想将ArrayList
转换为数组?
Object[] array = new Object[list.size()]; array = list.toArray(array);
选择合适的class级。
List list = getList(); Object[] array = new Object[list.size()]; for (int i = 0; i < list.size(); i++) { array[i] = list.get(i); }
或者只使用List#toArray()
List fooList = new ArrayList (); Foo[] fooArray = fooList.toArray(new Foo[0]);
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();
尝试通用方法List.toArray()
:
List list = Arrays.asList("Foo", "Bar", "Gah"); String array[] = list.toArray(new String[list.size()]); // array = ["Foo", "Bar", "Gah"]