数组转List
String[] staffs = new String[]{"Tom", "Bob", "Jane"};
List staffsList = Arrays.asList(staffs);
需要注意的是， Arrays.asList() 返回一个受指定数组决定的固定大小的列表。 所以不能做 add 、 remove 等操作，否则会报错。
List staffsList = Arrays.asList(staffs);
staffsList.add("Mary"); // UnsupportedOperationException
staffsList.remove(0); // UnsupportedOperationException
如果想再做增删操作呢？将数组中的元素一个一个添加到列表，这样列表的长度就不固定了，可以进行增删操作。
List staffsList = new ArrayList<String>();
for(String temp: staffs){
staffsList.add(temp);
}
staffsList.add("Mary"); // ok
staffsList.remove(0); // ok
数组转Set
String[] staffs = new String[]{"Tom", "Bob", "Jane"};
Set<String> staffsSet = new HashSet<>(Arrays.asList(staffs));
staffsSet.add("Mary"); // ok
staffsSet.remove("Tom"); // ok
List转数组
String[] staffs = new String[]{"Tom", "Bob", "Jane"};
List staffsList = Arrays.asList(staffs);
Object[] result = staffsList.toArray();
List转Set
String[] staffs = new String[]{"Tom", "Bob", "Jane"};
List staffsList = Arrays.asList(staffs);
Set result = new HashSet(staffsList);
Set转数组
String[] staffs = new String[]{"Tom", "Bob", "Jane"};
Set<String> staffsSet = new HashSet<>(Arrays.asList(staffs));
Object[] result = staffsSet.toArray();
Set转List
String[] staffs = new String[]{"Tom", "Bob", "Jane"};
Set<String> staffsSet = new HashSet<>(Arrays.asList(staffs));
List<String> result = new ArrayList<>(staffsSet);
