Map排序和遍历

Posted 2022-12-07 lllllLiangjia

Map排序

        List<Map.Entry<Integer, Integer>> list = new ArrayList<>(map.entrySet());
        Collections.sort(list, new Comparator<Map.Entry<Integer,Integer>>() 
            @Override
            public int compare(Map.Entry<Integer,Integer> o1, Map.Entry<Integer,Integer> o2) 
                return o1.getValue().compareTo(o2.getValue());
            
        );

 

Map遍历两种方法

第一种

    System.out.println("通过Map.keySet遍历key和value：");
    for (String key : map.keySet()) 
        System.out.println("key= "+ key + " and value= " + map.get(key));
    

第二种用Entry方法数据量大时

    System.out.println("通过Map.entrySet遍历key和value");
    for (Map.Entry<String, String> entry : map.entrySet()) 
        System.out.println("key= " + entry.getKey() + " and value= " + entry.getValue());