1.String[]转list

String[] arr = {"a", "b"};  
List<String> list = Arrays.asList(arr);  //此集合无法操作添加元素
List<String> list1 = new ArrayList<String>(list); //此集合可操作元素

2.list转String[]

List<String> list = new ArrayList<>();    
list.add("a");    
list.add("b");    
String[] arr = list.toArray(new String[list.size()]);