通用方法

public class MapUtil {
public static <K, V extends Comparable<? super V>> Map<K, V> sortByValue(Map<K, V> map) {
List<Map.Entry<K, V>> list = new LinkedList<Map.Entry<K, V>>(map.entrySet());
Collections.sort(list, new Comparator<Map.Entry<K, V>>() {
public int compare(Map.Entry<K, V> o1, Map.Entry<K, V> o2) {
return (o1.getValue()).compareTo(o2.getValue());
}
}); Map<K, V> result = new LinkedHashMap<K, V>();
for (Map.Entry<K, V> entry : list) {
result.put(entry.getKey(), entry.getValue());
}
return result;
}
}

java7

public static <K, V extends Comparable<? super V>> Map<K, V> sortByValue(Map<K, V> map) {
List<Map.Entry<K, V>> list = new LinkedList<>(map.entrySet());
Collections.sort(list, new Comparator<Map.Entry<K, V>>() {
@Override
public int compare(Map.Entry<K, V> o1, Map.Entry<K, V> o2) {
return (o1.getValue()).compareTo(o2.getValue());
}
}); Map<K, V> result = new LinkedHashMap<>();
for (Map.Entry<K, V> entry : list) {
result.put(entry.getKey(), entry.getValue());
}
return result;
}

java8

 public static <K, V extends Comparable<? super V>> Map<K, V> sortByValue(Map<K, V> map) {
Map<K, V> result = new LinkedHashMap<>();
Stream<Entry<K, V>> st = map.entrySet().stream(); st.sorted(Comparator.comparing(e -> e.getValue())).forEach(e -> result.put(e.getKey(), e.getValue())); return result;
}

  

05-12 00:30