string数组的定义有三种：
String arr[] = new String[10]; //创建一个长度为10的String 类型数组。
String arr[] = {"去去去","发的"};
String[] str = new String[]{"","","","",""};
可以使用List方便
String[]转List
String[] arr = new String[]{"aa1","aa2","aa3"};
List<String> list = Arrays.asList(arr);
List转String[]
List<String> list = new ArrayList<String>();
list.add("aa1");
list.add("aa2");
list.add("aa3");
String[] arr = list.toArray(new String[list.size()]);