保证一个类仅有一个实例,并提供一个访问它的全局访问点。
class DBMysqlHisapi2
{
private DBMysqlHisapi2() { }//不允许实例化这个类
private volatile static DBMysql _instance = null;//单例的保存对象
private static readonly object lockHelper = new object();//锁的钥匙
public static DBMysql Conn()
{
if (_instance == null)
{
lock (lockHelper)//加锁是为了防止多线程时的并发
{
if (_instance == null)
{
string hisapiMysqlConnection = Xml.Instance().getNodeText("hisapiMysqlConnection");
_instance = DBMysql.getInstance(hisapiMysqlConnection);
}
}
}
return _instance;
}
}