操作数据库：
http://blog.csdn.net/lmj623565791/article/details/39122981
http://www.it165.net/pro/html/201401/9026.html
http://blog.csdn.net/krislight/article/details/9391455
http://blog.csdn.net/u012565107/article/details/21546829
加密
http://blog.csdn.net/ab601026460/article/details/20618157
