Map根据value排序、List排序

Map根据value排序

传进来一个map可以返回一个根据value排序的map

public static Map sortByValue(Map map) {

        List<Map.Entry<String, String>> list = new ArrayList<Map.Entry<String, String>>(map.entrySet());
        Collections.sort(list, new Comparator<Map.Entry<String, String>>() {
            public int compare(Map.Entry<String, String> o1, Map.Entry<String, String> o2) {
                return o1.getValue().compareTo(o2.getValue());//升序
                //return o2.getValue().compareTo(o1.getValue()); 降序
            }
        });

        Map newMap = new LinkedHashMap();
        Iterator<Map.Entry<String, String>> iter = list.iterator();
        Map.Entry tmpEntry = null;
        while (iter.hasNext()) {
            tmpEntry = iter.next();
            newMap.put(tmpEntry.getKey(), tmpEntry.getValue());
        }

        return newMap;
    }

List排序

Collections.sort(list);//升序
Collections.reverse(list);//降序