response.setData("onlineUsers", new CopyOnWriteArrayList<User>(DataBuffer.online
response.setData("onlineUsers", new CopyOnWriteArrayList<User>(DataBuffer.onlineUsersMap.values()));
总是说new CopyOnWriteArrayList<User>没有定义，这是怎么回事？

[解决办法]
List<User> list=new CopyOnWriteArrayList<User>();


[解决办法]
response.setData("onlineUsers","i kown you")
response.setData("onlineUsers",new String("i kown you"))
String tttt="i kown you";
response.setData("onlineUsers",tttt)

类似的,定义了一个新对象CopyOnWriteArrayList,只是无用其他变量来引用它