简单的一个多线程下载demo,用来包括对进度条的刷新，数据库的操作-A simple multi-threaded download demo, including the progress bar to refresh, database operations, etc.

一个多线程并发服务器程序，服务端启动后，监听客户端连接，接受客户端消息，并操作数据库。-A multi-threaded concurrent server program, the server starts listening for client connections, the client accepts the message, and operation of the database.

实现多线程服务器，实现GPS定位点坐标和工作状态解析、存储、以及安全距离判断、实时发送报警信息、数据库使用mysql。-Multi-threaded server, realize GPS positioning coordinates and work state analysis, storage, and security the judge, send real-time alarm information, mysql.