public static void main(String[] args) { int count = 0; Map<String, Object> map = new HashMap<>(); map.put("person", "张三"); testParam(count, map); System.out.println("count: " + count); // 0 System.out.println("person: " + map.get("person")); // 李四 } private static void testParam(int count, Map<String, Object> map) { count = count + 1; map.put("person", "李四"); }