今天,发现我们的一个Windows Service无法正常停止,无奈之下只能杀了进程。
为了找到原因,我在本地进行调试,发现程序里用到了多线程,而代码正是卡在了workThread.Abort()语句而无法停止。
为什么不能Abort? 继续看线程调用的方法的代码,发现没有什么特殊的代码,只是在其中用了Thread.Sleep进行长时间等待。
难道是这个引起的? 写了一个测试程序验证,
class Program { private readonly Thread workThread; public Program() { workThread = new Thread(DoWork); } static void Main( string [] args) { new Program().Work(); Console.ReadLine(); } private void Work() { workThread.Start(); Thread.Sleep(1 * 1000); Console.WriteLine( "aborting" ); workThread.Abort(); Console.WriteLine( "aborted" ); } private void DoWork() { Console.WriteLine( "started" ); Thread.Sleep(300 * 1000); } } |
发现可以正常终止。
started
aborting
aborted
再仔细检查,发现其中一处Thread.Sleep放在了finally块中,修改测试代码
class Program { private readonly Thread workThread; public Program() { workThread = new Thread(DoWork); } static void Main(string[] args) { new Program().Work(); Console.ReadLine(); } private void Work() { workThread.Start(); Thread.Sleep(1 * 1000); Console.WriteLine("aborting"); workThread.Abort(); Console.WriteLine("aborted"); } private void DoWork() { try { Console.WriteLine("started"); } catch (Exception) { throw; } finally { for (int i = 0; i < 3; i++) { Console.WriteLine("ThreadState:" + workThread.ThreadState); Thread.Sleep(1000); } } } }
输出:
started