1、ConcurrentHashMap类:调用ConcurrentHashMap()构造函数,创建cMap对象

1、ConcurrentHashMap类:调用ConcurrentHashMap(int initialCapacity),创建对象cMap,并指定初始化容量参数

1、ConcurrentHashMap类:调用ConcurrentHashMap(int initialCapacity, float loadFactor),创建cMap对象,指定容量,加载因子

1、ConcurrentHashMap类:调用ConcurrentHashMap(int initialCapacity, float loadFactor, int concurrencyLevel),创建cMap对象,指定容量,加载因子,同时加载线程数

1、ConcurrentHashMap类:调用ConcurrentHashMap(Map<? extends K,? extends V> m),创建cMap对象
