1.ArrayList-->數組
List<String> list = new ArrayList<String>();
String[] array = (String[]) list.toArray();
2.數組-->ArrayList
List<String> list = null;
String[] array = new String[3];
list = Arrays.asList(array);
//用Arrays.asList()方法得到的List對象是長度固定的
//當對list進行remove、add等操作時會出UnsupportedOperationException異常
//可用下述方式解決
list = new ArrayList<String>(Arrays.asList(array));