使用"对象引用未设置为对象实例"运行Quartz作业时出错

Question

我有一个Quartz作业,Application_Start在此期间设置Global.asax.cs

protected void Application_Start()
{
    AreaRegistration.RegisterAllAreas();
    RouteConfig.RegisterRoutes(RouteTable.Routes);
    Logger.log("About to Setup Retry Job");
    JobScheduler.Start();
}

这会调用该Start方法,然后调度作业.

作业每20秒运行一次并抛出异常.这是我的工作.

public class RetryTempJob : IJob
{
    public async Task Execute(IJobExecutionContext context)
    {
        try
        {
            Logger.log("Executing Job");
            new ProcessOrder().retryFailedOrders();
            //Logger.log("Done Executing Syspro Job");
            await Console.Error.WriteLineAsync("Done Executing Syspro Job");
        }
        catch (Exception se)
        {
            await Console.Error.WriteLineAsync("" + se.InnerException);
        }
    }
}

此行引发异常Logger.log("Executing Job");.这是一个静态方法,它打开一个日志文件并写入它.此方法适用于我的网站中的其他位置.

以下是异常消息:{"对象引用未设置为对象的实例."}

InnerException为NULL.这是堆栈:

DarwinsShoppingCart.dll!DarwinsShoppingCart.SharedClasses.JobScheduler.RetrySyspro.Execute(Quartz.IJobExecutionContext context) Line 69 C#
    Quartz.dll!Quartz.Core.JobRunShell.Run(System.Threading.CancellationToken cancellationToken)    Unknown
    mscorlib.dll!System.Runtime.CompilerServices.AsyncTaskMethodBuilder.Start<Quartz.Core.JobRunShell.<Run>d__9>(ref Quartz.Core.JobRunShell.<Run>d__9 stateMachine)    Unknown
    Quartz.dll!Quartz.Core.JobRunShell.Run(System.Threading.CancellationToken cancellationToken)    Unknown
    Quartz.dll!Quartz.Core.QuartzSchedulerThread.Run.AnonymousMethod__0()   Unknown
    mscorlib.dll!System.Threading.Tasks.Task<System.Threading.Tasks.Task>.InnerInvoke() Unknown
    mscorlib.dll!System.Threading.Tasks.Task.Execute()  Unknown
    mscorlib.dll!System.Threading.Tasks.Task.ExecutionContextCallback(object obj)   Unknown
    mscorlib.dll!System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)   Unknown
    mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)   Unknown
    mscorlib.dll!System.Threading.Tasks.Task.ExecuteWithThreadLocal(ref System.Threading.Tasks.Task currentTaskSlot)    Unknown
    mscorlib.dll!System.Threading.Tasks.Task.ExecuteEntry(bool bPreventDoubleExecution) Unknown
    mscorlib.dll!System.Threading.Tasks.Task.System.Threading.IThreadPoolWorkItem.ExecuteWorkItem() Unknown
    mscorlib.dll!System.Threading.ThreadPoolWorkQueue.Dispatch()    Unknown
    mscorlib.dll!System.Threading._ThreadPoolWaitCallback.PerformWaitCallback() Unknown

这是我的Logger类代码

public static void log(string strLog)
{
    StreamWriter log;
    FileStream fileStream = null;
    DirectoryInfo logDirInfo = null;
    FileInfo logFileInfo;
    string username = Environment.UserName;
    string logFilePath = HttpContext.Current.Server.MapPath("~/log/Log.txt");
    logFileInfo = new FileInfo(logFilePath);
    logDirInfo = new DirectoryInfo(logFileInfo.DirectoryName);
    double fileSize = ConvertBytesToMegabytes(logFileInfo.Length);
    if (fileSize > 30)
    {
        string FileDate = DateTime.Now.ToString().Replace("/", "-").Replace(":", "-");
        string oldfilepath = HttpContext.Current.Server.MapPath("~/log/log-" + FileDate + ".txt");
        File.Move(logFileInfo.FullName, oldfilepath);
    }
    if (!logFileInfo.Exists)
    {
        fileStream = logFileInfo.Create();
    }
    else
    {
        fileStream = new FileStream(logFilePath, FileMode.Append);
    }
    log = new StreamWriter(fileStream);

    log.WriteLine(DateTime.Now.ToString("MM-dd HH:mm:ss") + " " + username + " " + strLog);
    log.Close();
}

Answer 1

HttpContext使用 Quarz Job 时没有。它在单独的线程中运行。所以在我使用的带有 Quarz Job 的网站上HostingEnvironment

所以代替

HttpContext.Current.Server.MapPath("~/log/Log.txt")

使用

using System.Web.Hosting;

HostingEnvironment.MapPath("~/log/Log.txt");