1.拿到所有键，放入set集合，遍历取键，用get方法取值。

    public void test1() {
        HashMap<Integer, String> map = new HashMap<>();
        map.put(1,"奥");
        map.put(2,"运");
        map.put(3,"会");
        Set<Integer> set = map.keySet();
        for (Integer i: set) {
            System.out.println(integer+"="+map.get(i));
        }
    }

2.获取键值对集合（entry集合），遍历集合，用Entry中的getKey()和getValue()方法获取键和值。

    public void test2() {
        map<Integer, String> map= new HashMap<>();
        map.put(1,"奥");
        map.put(2,"运");
        map.put(3,"会");
        Set<Map.Entry<Integer, String>> entries = map.entrySet();
        for (Map.Entry<Integer, String> entry : entries) {
            Integer key = entry.getKey();
            String value = entry.getValue();
            System.out.println(key+"  "+value);
        }
    }