Question

如何判断Map中的key或value类型

Answer 1

public class Test {
\x09/**
\x09* @param args
\x09*/
\x09public static void main(String[] args) {
\x09\x09// TODO Auto-generated method stub
\x09\x09HashMap map = new HashMap();
\x09\x09map.put("key1","value1");
\x09\x09map.put("key2","value2");
\x09\x09map.put("key3","value3");
\x09\x09Iterator keys = map.keySet().iterator();
\x09\x09while(keys.hasNext()){
\x09\x09\x09String key = (String)keys.next();
\x09\x09\x09if("key2".equals(key)){
\x09\x09\x09\x09System.out.println("这里面有key2");
\x09\x09\x09}
\x09\x09}
\x09}
}

Answer 2

Map map =new HashMap();
map.put("aa", "asdfa");
map.put(1, "");
map.put("dd", "sdsd");
Set keys = map.keySet();
Iterator it = keys.iterator();
while (it.hasNext()){
Object key = it.next();
Object value = map.get(key);
System.out.println("key类型："+key.getClass().getName());
System.out.println("值类型："+value.getClass().getName());
}