//创建book对象
//Book2 book=new Book2();
//创建TreeMap对象
TreeMap tm=new TreeMap();
tm.put(new Book2("1896-09-01","平方的世界"),"1001");
tm.put(new Book2("2012-12-01","白说"),"1002");
tm.put(new Book2("2014-09-01","创业维艰"),"1003");
//获取迭代器
Set> set=tm.entrySet();
Iterator it=set.iterator();
while(it.hasNext()){
System.out.println(it.next());
}
为什么只添加了一个键值,其他的都没有添加进去,求解,谢谢了