Map的value值降序排序与升序排序(java)

Dear 丶 2022-05-29 12:45 280阅读 0赞

**本文为原创博客，仅供技术学习使用。未经允许，禁止转载**

# 程序 #

package test;
    
    import java.util.Collections;
    import java.util.Comparator;
    import java.util.LinkedHashMap;
    import java.util.LinkedList;
    import java.util.List;
    import java.util.Map;
    import java.util.TreeMap;
    
    
    public class Test {
        public static Map<Integer, Double> Probs = new TreeMap<Integer, Double>();
        public static void main(String[] args) {
            Probs.put(1, 0.5);
            Probs.put(2, 1.5);
            Probs.put(3, 0.2);
            Probs.put(4, 10.2);
            Probs = sortByValueDescending(Probs);
            System.out.println("基于value值的降序，排序输出结果为：");
            for (Map.Entry<Integer, Double> entry : Probs.entrySet()) {
                System.out.println("key= " + entry.getKey() + " and value= " + entry.getValue());
            }
            System.out.println();
            System.out.println("基于value值的升序，排序输出结果为：");
            Probs = sortByValueAscending(Probs);
            for (Map.Entry<Integer, Double> entry : Probs.entrySet()) {
                System.out.println("key= " + entry.getKey() + " and value= " + entry.getValue());
            }
    
        }
        //降序排序
        public static <K, V extends Comparable<? super V>> Map<K, V> sortByValueDescending(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>>()
            {
                @Override
                public int compare(Map.Entry<K, V> o1, Map.Entry<K, V> o2)
                {
                    int compare = (o1.getValue()).compareTo(o2.getValue());
                    return -compare;
                }
            });
    
            Map<K, V> result = new LinkedHashMap<K, V>();
            for (Map.Entry<K, V> entry : list) {
                result.put(entry.getKey(), entry.getValue());
            }
            return result;
        }
        //升序排序
        public static <K, V extends Comparable<? super V>> Map<K, V> sortByValueAscending(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>>()
            {
                @Override
                public int compare(Map.Entry<K, V> o1, Map.Entry<K, V> o2)
                {
                    int compare = (o1.getValue()).compareTo(o2.getValue());
                    return compare;
                }
            });
    
            Map<K, V> result = new LinkedHashMap<K, V>();
            for (Map.Entry<K, V> entry : list) {
                result.put(entry.getKey(), entry.getValue());
            }
            return result;
        }
    
    }

# 输出结果 #

![这里写图片描述][SouthEast]

[SouthEast]: /images/20220529/c14f3d237526406c955f8cc86551458e.png