private static function initDB()
{
if (self::$db === NULL) {
self::$db = new DbUtil(DbConfig::getHost(), DbConfig::getUserName(), DbConfig::getUserPwd(), DbConfig::getDbName());
self::$login_time = time();
} else {
$cur = time();
if ($cur - self::$login_time > 60) {
self::$db->close();
self::$db->init(DbConfig::getHost(), DbConfig::getUserName(), DbConfig::getUserPwd(), DbConfig::getDbName());
self::$login_time = $cur;
}
}
return TRUE;
}