map集合之——加强for和迭代器遍历，集合的双重遍历

public static void main(String[] args) {
HashMap<String, String> java01=new HashMap<>();
java01.put("港台明星", "刘德华");
java01.put("大陆明星", "赵薇");
HashMap<String, String> java02=new HashMap<>();
java02.put("阿里帝国", "马云");
java02.put("腾讯帝国", "马化腾");
Map<String, HashMap<String, String>> itcast=new HashMap<>();
itcast.put("明星组", java01);
itcast.put("创业大佬", java02);

//增强for的双重遍历
Set<String> keys1=itcast.keySet();
for (String key : keys1) {
Set<String>keys11=itcast.get(key).keySet();
System.out.println(key);
for (String string : keys11) {
System.out.println(string+itcast.get(key).get(string));
}

}

System.out.println("========================================================");

//定义entry关系遍历itcast数组,iterator的双重遍历
Set<Entry<String, HashMap<String, String>>> keys2=itcast.entrySet();
Iterator<Entry<String, HashMap<String, String>>> iterator=keys2.iterator();

while (iterator.hasNext()) {
Entry<String, HashMap<String, String>> hash=iterator.next();
System.out.println(hash.getKey());
//取出itcast中的数组，将值数组赋值给新建数组hash2
HashMap<String,String> hash2=hash.getValue();

//定义entry关系，用迭代器遍历itcast的值的数组
Set<Entry<String, String>> entry=hash2.entrySet();
Iterator<Entry<String, String>> it=entry.iterator();

while (it.hasNext()) {
Entry<String, String> key=it.next();
System.out.println(hash.getKey()+key.getKey()+key.getValue());

}

}
}