想起来就提问，怕以后忘了，Iterator的泛型该怎么写？

Question

Map<String,String> map=new HashMap<String,String>();
map.put("1", "zhangsan");
map.put("2", "lisi");
map.put("3", "wangwu");

Iterator it=map.entrySet().iterator();
while(it.hasNext()){
Entry<String,String> obj=(Entry<String,String>)it.next();
System.out.println(obj.getKey());
System.out.println(obj.getValue());
}

Answer 1

对啊,看下API应该有很详细的说明的,作为程序员应该学会自己查看API

Answer 2

Map<String,String> map=new HashMap<String,String>();
map.put("XXX", "XXX");
                ......
Iterator<Map.Entry<String, String>> it=map.entrySet().iterator();
while(it.hasNext()){
Map.Entry<String, String> ent=it.next();
System.out.println(ent.getKey());
System.out.println(ent.getValue());
}

Answer 3

Iterator<?>  it = Map1.keySet().iterator();

Answer 4

如果是keyset，应该是 Iterator<String>  it = Map1.keySet().iterator();  ??