利用hashtable实现网络广播，其中分inject.java和peer.java两部份，inject插入要广播内容，peer端接收显示并转发，过程中判断是否来自同一IP和端口，并检查是否是原数据。文件为RAR压缩格式。-Hashtable realize the use of webcasts, in which sub-inject.java and peer.java two parts, inject insert to broadcast content, peer-side receiver display and forwarding, the process to determine whether from the same IP and port, and check whether the original data. Document for the RAR compression format.