我有以下情况,我尝试按键排序地图值。在键顺序之后,第一个值必须是按顺序排列的值。
import java.util.Comparator;
import java.util.Map;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Maps;
import com.google.common.collect.Ordering;
public class MyEnumKeySortTest {
enum Key{
key1, key2
}
enum Door{
door1, door2
}
public static void main(String[] args) {
Map<Key, Door> test = ImmutableMap.<Key, Door> of(Key.key1, Door.door1, Key.key2, Door.door2);
printValues(test);
Comparator<Key> comparator = Ordering.explicit(Key.key1);
/*
* should print
*
* door1
* door2
*/
test = Maps.newTreeMap(comparator);
printValues(test);
Comparator<Key> comparator2 = Ordering.explicit(Key.key2);
/*
* should print
*
* door2
* door1
*/
test = Maps.newTreeMap(comparator2);
printValues(test);
}
private static void printValues(Map<Key, Door> test) {
System.out.println("==========================================================");
for(Door r : test.values()){
System.out.println(r.name());
}
}
}
答案 0 :(得分:0)
将Map.Entry放入列表中,并使用对值进行排序的比较器对其进行排序 -
List list = new ArrayList(map.entrySet());
Collections.sort(list, new Comparator() {
@Override
public int compare(Entry e1, Entry e2) {
return e1.getKey().compareTo(e2.getKey());
}
});
或者可以使用SortedMap
之类的一些实现 - TreeMap
。在这种情况下,所有密钥可能必须实现Comparable