Map<Integer, String> keyValues = new HashMap<Integer, String>();
        keyValues.put(1, "1");
        keyValues.put(2, "22");
        keyValues.put(3, "333");
        keyValues.put(3, "三三三");
        for (Map.Entry<Integer, String> entry : keyValues.entrySet()) {
            System.out.println(entry.getKey()+" "+entry.getValue());
        }

1 1
2 22
3 三三三

        Map<Integer, String> keyValues = new HashMap<Integer, String>();
        keyValues.put(1, "1");
        keyValues.put(2, "22");
        keyValues.put(3, "333");
        keyValues.put(3, "三三三");
        
        Map<Integer, String> keyValues2 = new HashMap<Integer, String>();
        keyValues.put(4, "4444");
        keyValues.put(5, "55555");
        keyValues.putAll(keyValues2);
                
        for (Map.Entry<Integer, String> entry : keyValues.entrySet()) {
            System.out.println(entry.getKey()+" "+entry.getValue());
        }

1 1
2 22
3 三三三
4 4444
5 55555

        System.out.println(keyValues.get(5));// 获取键对应的值
        boolean isTrue = keyValues.containsKey(3);// 是否包含某个键
        int count = keyValues.size();// 键值对个数
        Set<Integer> keys = keyValues.keySet();// 获取键的集合
        String output = keyValues.remove(5);// 移除一个键值，如果不存在返回null
        keyValues.clear();// 清除所有键值
        boolean isEmpty = keyValues.isEmpty();// 键值对个数是否为空