用MYSQL中的加密函数来加密：PASSWORD（）

加密：<sql:update var="user" dataSource="${bookdev}">
  insert into user values("","${param.userName}",password("${param.userPwd}"),"${param.userLevel}")
</sql:update>
解密：<sql:query var="query" dataSource="${bookdev}">
  select * from user where userName=\'${param.userName}\' and
  userPwd=password(\'${param.userPwd}\')
</sql:query>