treeMap按值排序

Myth丶恋晨 2021-09-07 06:11 558阅读 0赞

## 1、默认按key排序 ##

//treeMap
    private static void test01(){
        TreeMap<String, Object> treeMap = new TreeMap<String, Object>();
        treeMap.put("zs", 15);
        treeMap.put("ls",18);
        treeMap.put("ww", 22);
        String key = treeMap.firstEntry().getKey();
        String key2 = treeMap.lastEntry().getKey();
        System.out.println(key);
        System.out.println(key2);
    }

### 2、treeMap按值排序 ###

private static void test02(){
        TreeMap<String, Integer> treeMap = new TreeMap<String, Integer>();
        treeMap.put("zs", 18);
        treeMap.put("ls",25);
        treeMap.put("ww", 22);
        
        Set<Entry<String,Integer>> entrySet = treeMap.entrySet();
        List<Entry<String,Integer>> list = new ArrayList<Entry<String,Integer>>(entrySet);
        Collections.sort(list, new Comparator<Entry<String, Integer>>() {
            public int compare(Entry<String, Integer> entry1, Entry<String, Integer> entry2) {
                return entry1.getValue().compareTo(entry2.getValue());
            }
        });
        
        for(Entry<String, Integer> entry : list) {
            System.out.println(entry.getKey()+":"+entry.getValue());
        }
    }

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