1、集合-->数组：toArray（）

Collection coll = new ArrayList();
coll.add(133);
coll.add(53);
		
Object[] array = coll.toArray();

2、数组-->集合：调用Arrays类的静态方法asList()

List<String> list = Arrays.asList(new String[]{"as","wa"});
	
List list1 = Arrays.asList(new int[]{12,123});
System.out.println(list1.size()); //返回值为1
		
List list2 = Arrays.asList(new Integer[]{12,123});
System.out.println(list2.size()); //返回值为2