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; }