2. public static void sort(Map<Integer, Integer> map) { List<Integer> list = new ArrayList<Integer>(); Iterator<Integer> iter = map.values().iterator(); while (iter.hasNext()) { list.add(iter.next()); } Collections.sort(list); Collections.reverse(list); System.out.println(list);
int i = 1; for(Iterator<Integer> ite = list.iterator();ite.hasNext();) { map.put(i, ite.next()); i++; } System.out.println(map); }
要重新写个compartorMap本来就是无序的,这是啥意思?
TreeMap<String, Object> tm = new TreeMap<String, Object>(
new Comparator<String>() {
public int compare(String o1, String o2) {
return o1.compareTo(o2);
}
});
for (Iterator it = set.iterator(); it.hasNext();) {
Object o = it.next();
String item = (String) o;
tm.put(item + " " + item, item); }
return tm.values();
}
import java.util.ArrayList;
import java.util.List;
import java.util.Collections;public class Sorting {
public static void main(String[] args) {
List<Integer> list = new ArrayList<Integer>();
list.add(6);
list.add(5);
list.add(3);
list.add(1);
list.add(2);
list.add(4);
Collections.sort(list);
System.out.println(list);
Collections.reverse(list);
System.out.println(list);
}
}
public static void sort(Map<Integer, Integer> map) {
List<Integer> list = new ArrayList<Integer>(); Iterator<Integer> iter = map.values().iterator();
while (iter.hasNext()) {
list.add(iter.next());
}
Collections.sort(list);
Collections.reverse(list);
System.out.println(list);
int i = 1;
for(Iterator<Integer> ite = list.iterator();ite.hasNext();) {
map.put(i, ite.next());
i++;
}
System.out.println(map);
}
map不是实现的collection接口。