不懂，求大神教教，是遍历，然后再取类中的key和value吗

public void browselist(Map<String, HomeworkList> map){


    Set<Map.Entry<String, HomeworkList>> set = map.entrySet();
    for(Iterator<Map.Entry<String, HomeworkList>> it = set.iterator();
            it.hasNext();){

        Map.Entry<String, HomeworkList> entry = (Map.Entry<String, HomeworkList>)it.next();

        System.out.println(entry.getKey()+"-"+entry.getValue());
    }

}

是的，遍历map，得到key和value，注意这个value是HomeworkList

但是其实你写

 for (Map.Entry<String, HomeworkList> entry : map) {
    System.out.println(entry.getKey()+"-"+entry.getValue());
}

就可以了，功能一样

 public void browselist(Map<String, HomeworkList> map){


    Set<Map.Entry<String, HomeworkList>> set = map.entrySet();
    for(Iterator<Map.Entry<String, HomeworkList>> it = set.iterator();
            it.hasNext();){

        Map.Entry<String, HomeworkList> entry = (Map.Entry<String, HomeworkList>)it.next();

        System.out.println(entry.getKey()+"-"+entry.getValue().getName());//getName换成你HomeworkList里面的值，如果Homework是你的实体的话，
                //假设里面是一个List你可以这样.
                for(Homework hm : entry.getValue()){
                    System.out.println(hm.getName()); //这样,.
                }
    }

}

对啊，就是遍历获取map中的key-value对