先看api:
Class HashMap<K,V>
java.lang.Object
java.util.AbstractMap<K,V>
java.util.HashMap<K,V>
Type Parameters:
K - the type of keys maintained by this map
V - the type of mapped values
All Implemented Interfaces:
Serializable, Cloneable, Map<K,V>
Direct Known Subclasses:
LinkedHashMap, PrinterStateReasons
!!敲黑板!!
一定要注意,HashMap 是泛型类(class),它实现了Map接口。
请不要实例化接口!
HashMap<String,String> t=new map<String,String>();
HashMap t=new map<String,String>();
//我的花式写错过程
正确写法:
HashMap map = new HashMap<Integer,String>();
ps:终于会设置markdown的颜色了!