一. 应用场景

开发一个课件在线学习功能，要求将WORD, EXCEL, PPT类型课件可在线打开学习；最初设想使用第三方office插件，无奈价格太高放弃使用；

我们最终的方案是：利用office自身的另存为功能，在服务器将上传的office文件转化为pdf格式，然后网页打开pdf文件实现在线学习功能；

项目实现方案：新建一个windows自启的service安装在服务器，这个服务里面会建立一个HttpListener，用于监听文件转换的请求，请求来了后交给ServiceHandle处理，ServiceHandle会调用ConvertHelper把指定目录下的office文件转化为pdf，并放在相同目录下，以供在线学习使用；

二. 工具及环境

VS2019

Office：本地开发2016版；服务器2010版

开发环境 win10

服务器环境 windows server 2012 R2

VS开发使用到的nuget包：NetOffice

三. 创建windows server项目

基本按照这个思路开发出一个基础service完全没问题；这里需要提醒下的是：项目的文件路径不要带有空格，否则在执行bat批处理操作时会出现问题。

四. 使用NetOffice实现文件转换

上面只是创建一个服务， 真正转换的核心功能还没开始，这时我们需要利用NetOffice插件；

项目目录：

image.png

利用nuget包管理器安装所需包，这是项目的packages.config文件：

转换核心代码：ConvertHelper.cs

public class ConvertHelper

{

public static void ConvetToPdf(string sourcePath, string targetPath)

{

if (!File.Exists(sourcePath))

{

throw new Exception(string.Format("文件{0}不存在", sourcePath));

}

if (File.Exists(targetPath))

{

throw new Exception(string.Format("目标文件{0}已存在", targetPath));

}

LogHelper.Info("开始转换:" + Path.GetFileName(sourcePath));

var targetDirectory = Path.GetDirectoryName(targetPath);

if (!Directory.Exists(targetDirectory))

{

Directory.CreateDirectory(targetDirectory);

}

var ext = Path.GetExtension(sourcePath).ToLower();

if (ext == ".ppt" || ext == ".pptx")

{

ConvertPptToPdf(sourcePath, targetPath);

}

else if (ext == ".doc" || ext == ".docx")

{

ConvertDocumentToPdf(sourcePath, targetPath);

}

else if (ext == ".xls" || ext == ".xlsx")

{

ConvertExcelToPdf(sourcePath, targetPath);

}

else

{

LogHelper.Info("{0}不支持转换pdf", sourcePath);

return;

}

if (File.Exists(targetPath))

{

LogHelper.Info("转换成功:" + Path.GetFileName(sourcePath));

}

else

{

LogHelper.Info("转换失败:" + Path.GetFileName(sourcePath));

}

}

///

/// 转换ppt文件到pdf文件(不支持超时终止)

///

///

///

private static void ConvertPptToPdf(string sourcePath, string targetPath)

{

NetOffice.PowerPointApi.Application application = null;

NetOffice.PowerPointApi.Presentation presentation = null;

var cts = new CancellationTokenSource();

var thread = new Thread(() =>

{

try

{

application = new NetOffice.PowerPointApi.Application();

presentation = application.Presentations.Open(sourcePath, true, NetOffice.OfficeApi.Enums.MsoTriState.msoTrue, false);

presentation.SaveCopyAs(targetPath, NetOffice.PowerPointApi.Enums.PpSaveAsFileType.ppSaveAsPDF);

}

catch (Exception ex)

{

if (ex.InnerException != null && ex.InnerException is ThreadAbortException)

{

LogHelper.Info("ConvertPptToPdf: {0}操作超时", Path.GetFileName(sourcePath));

}

else

{

LogHelper.Error(ex, "ConvertPptToPdf: {0}出现异常", Path.GetFileName(sourcePath));

}

}

finally

{

if (presentation != null)

{

presentation.Close();

presentation = null;

}

if (application != null)

{

application.Quit();

application.Dispose();

application = null;

}

//killProccess("POWERPNT");

}

});

cts.Token.Register(() =>

{

thread.Abort();

});

cts.CancelAfter(Program.MaxThreads * 1000);

thread.Start();

thread.Join();

GC.Collect();

GC.WaitForPendingFinalizers();

}

///

/// 转换word文件到pdf文件(支持超时终止)

///

///

///

private static void ConvertDocumentToPdf(string sourcePath, string targetPath)

{

NetOffice.WordApi.Application application = null;

NetOffice.WordApi.Document document = null;

var cts = new CancellationTokenSource();

var thread = new Thread(() =>

{

try

{

application = new NetOffice.WordApi.Application();

document = application.Documents.Open(sourcePath);

document.ExportAsFixedFormat(targetPath, NetOffice.WordApi.Enums.WdExportFormat.wdExportFormatPDF);

}

catch (Exception ex)

{

if (ex.InnerException != null && ex.InnerException is ThreadAbortException)

{

LogHelper.Info("ConvertDocumentToPdf: {0}操作超时", Path.GetFileName(sourcePath));

}

else

{

LogHelper.Error(ex, "ConvertDocumentToPdf: {0}出现异常", Path.GetFileName(sourcePath));

}

}

finally

{

if (document != null)

{

document.Close();

document = null;

}

if (application != null)

{

application.Quit();

application.Dispose();

application = null;

}

//killProccess("WINWORD");

}

});

cts.Token.Register(() =>

{

thread.Abort();

});

cts.CancelAfter(Program.MaxThreads * 1000);

thread.Start();

thread.Join();

GC.Collect();

GC.WaitForPendingFinalizers();

}

private static void ConvertExcelToPdf(string sourcePath, string targetPath)

{

NetOffice.ExcelApi.Application application = null;

NetOffice.ExcelApi.Workbook wookbook = null;

var cts = new CancellationTokenSource();

var thread = new Thread(() =>

{

try

{

application = new NetOffice.ExcelApi.Application();

wookbook = application.Workbooks.Open(sourcePath);

wookbook.ExportAsFixedFormat(NetOffice.ExcelApi.Enums.XlFixedFormatType.xlTypePDF, targetPath);

}

catch (Exception ex)

{

if (ex.InnerException != null && ex.InnerException is ThreadAbortException)

{

LogHelper.Info("ConvertExcelToPdf: {0}操作超时", Path.GetFileName(sourcePath));

}

else

{

LogHelper.Error(ex, "ConvertExcelToPdf: {0}出现异常", Path.GetFileName(sourcePath));

}

}

finally

{

if (wookbook != null)

{

wookbook.Close();

wookbook = null;

}

if (application != null)

{

application.Quit();

application.Dispose();

application = null;

}

//killProccess("EXCEL");

}

});

cts.Token.Register(() =>

{

thread.Abort();

});

cts.CancelAfter(Program.MaxThreads * 1000);

thread.Start();

thread.Join();

GC.Collect();

GC.WaitForPendingFinalizers();

}

public static void CleanProccess()

{

LogHelper.Info("CleanProccess Start");

killProccess("WINWORD");

killProccess("EXCEL");

LogHelper.Info("CleanProccess Finish");

}

private static void killProccess(string appName)

{

// Store all running process in the system

Process[] runingProcess = Process.GetProcesses();

for (int i = 0; i < runingProcess.Length; i++)

{

// compare equivalent process by their name

if (string.Equals(runingProcess[i].ProcessName, appName, StringComparison.OrdinalIgnoreCase))

{

try

{

// kill running process

runingProcess[i].Kill();

LogHelper.Info("Kill {0} [{1}]", appName, runingProcess[i].Id);

}

catch (Exception ex)

{

if (ex is System.InvalidOperationException)

{

//进程已经关闭

}

else

{

LogHelper.Error(ex, "Kill {0} [{1}] Error", appName, runingProcess[i].Id);

}

}

}

}

}

}

ServiceListener监听http请求，端口号默认8091；

public ServiceListener()

{

_stop = new ManualResetEvent(false);

_idle = new ManualResetEvent(false);

_busy = new Semaphore(Program.MaxThreads, Program.MaxThreads);

_listener = new HttpListener();

_listenerThread = new Thread(HandleRequests);

}

public void Start()

{

var url = String.Format(@"http://localhost:{0}/", Program.ListenerPort); // Port=8091

LogHelper.Info("Listenning Start:" + url);

_listener.Prefixes.Add(url);

_listener.Start();

_listenerThread.Start();

}

五. 系统调用http服务，转换文件

public void ConvertToPdf(string serviceUrl, string sourcePath, string pdfPath)

{

var url = $"{serviceUrl}?srcPath={sourcePath}&tarPath={pdfPath}";

using (var webClient = new WebClient())

{

var result = webClient.DownloadString(url);

}

}

至此，开发完毕，本地开发完成；

六. 本地测试功能

注册服务，执行注册服务.bat

启动服务，执行启动服务.bat

查看服务运行情况

image.png

但是测试转换时遇到了问题，日志错误为 "Office 检测到该文件有问题。为帮助保护您的计算机，此文件无法打开。"：

2020-05-02 09:04:22:248 Info [Thread9] 开始转换:a10a54166224453abdd8d4b809f15449.ppt

2020-05-02 09:04:25:379 Exception [Thread10] ConvertPptToPdf: a10a54166224453abdd8d4b809f15449.ppt出现异常 Exception:

System.Runtime.InteropServices.COMException (0x80004005): See inner exception(s) for details. ---> System.Reflection.TargetInvocationException: 调用的目标发生了异常。 ---> System.Runtime.InteropServices.COMException: Presentations.Open : Office 检测到该文件有问题。为帮助保护您的计算机，此文件无法打开。

--- 内部异常堆栈跟踪的结尾 ---

在 System.RuntimeType.InvokeDispMethod(String name, BindingFlags invokeAttr, Object target, Object[] args, Boolean[] byrefModifiers, Int32 culture, String[] namedParameters)

在 System.RuntimeType.InvokeMember(String name, BindingFlags bindingFlags, Binder binder, Object target, Object[] providedArgs, ParameterModifier[] modifiers, CultureInfo culture, String[] namedParams)

在 NetOffice.Invoker.MethodReturn(COMObject comObject, String name, Object[] paramsArray)

在 NetOffice.Invoker.MethodReturn(COMObject comObject, String name, Object[] paramsArray)

在 NetOffice.PowerPointApi.Presentations.Open(String fileName, Object readOnly, Object untitled, Object withWindow)

在 LMS.DocumentConvertService.ConvertHelper.LMS.DocumentConvertService\Service\ConvertHelper.cs:行号 75

2020-05-02 09:04:33:477 Info [Thread9] 转换失败:a10a54166224453abdd8d4b809f15449.ppt

我才用了其中2种较简单解决方案：

修改代码，在ProjectInstaller.cs中ProjectInstaller类中重载OnAfterInstall

[RunInstaller(true)]

public partial class ProjectInstaller : System.Configuration.Install.Installer

{

public ProjectInstaller()

{

InitializeComponent();

}

protected override void OnAfterInstall(IDictionary savedState)

{

try

{

base.OnAfterInstall(savedState);

System.Management.ManagementObject myService = new System.Management.ManagementObject(

string.Format("Win32_Service.Name='{0}'", this.serviceInstaller1.ServiceName));

System.Management.ManagementBaseObject changeMethod = myService.GetMethodParameters("Change");

changeMethod["DesktopInteract"] = true;

System.Management.ManagementBaseObject OutParam = myService.InvokeMethod("Change", changeMethod, null);

}

catch (Exception)

{

}

}

}

SC程序修改， 允许与桌面进行交互

用批处理的方式实现，加入如下命令到>启动服务.bat文件中

sc config MonitorService type=interact type=own

至此，本地开发环境转换服务成功运行。

接下来准备上服务器！！