Question

在我的Vaadin spring启动应用程序中，我需要将文件上传到服务器并将其保存在那里。

将文件本地上传到我的桌面工作正常，但我想将应用程序部署到服务器，所以我想将上传的文件保存在相对于我的应用程序的基本路径的目录中。

我创建了一个名为“input_files”的文件夹作为根应用程序文件夹（applicationName - ＆gt; input_files）的直接子项。上传文件时，该文件的内容应该写入此“input_files”文件夹中新创建的文件。

代码：

class FileReceiver implements Upload.Receiver, Upload.SucceededListener {
  private File file;

  public OutputStream receiveUpload(String filename, String mimeType) {
    String basePath = VaadinService.getCurrent().getBaseDirectory().getAbsolutePath();                
    FileOutputStream fileOutputStream;

    try {
      //this line would work:
      //file = new File("/Users/username/Desktop/input_files/" + filename);          

      //this line does not work:
      file = new File(basePath + "/input_files/" + filename);


      fileOutputStream = new FileOutputStream(file);
      labelFilename.setCaption(filename);
    }
    catch (final java.io.FileNotFoundException e) {
      new Notification("Could not open file", e.getMessage(), Notification.Type.ERROR_MESSAGE).show(Page.getCurrent());
      return null;
    }
    return fileOutputStream;
  }

  public void uploadSucceeded(Upload.SucceededEvent event) {

  }
};

重要的代码是：

file = new File(basePathOfApplication + "/input_files/" + filename);

此行不起作用。 input_files文件夹中没有创建文件。

********* UPDATE ************** ********************

屏幕上显示错误信息：

控制台中的错误消息：

com.vaadin.server.UploadException: Upload failed
    at com.vaadin.server.communication.FileUploadHandler.streamToReceiver(FileUploadHandler.java:631) [vaadin-server-8.1.0.jar:8.1.0]
    at com.vaadin.server.communication.FileUploadHandler.handleFileUploadValidationAndData(FileUploadHandler.java:460) [vaadin-server-8.1.0.jar:8.1.0]
    at com.vaadin.server.communication.FileUploadHandler.doHandleSimpleMultipartFileUpload(FileUploadHandler.java:413) [vaadin-server-8.1.0.jar:8.1.0]
    at com.vaadin.server.communication.FileUploadHandler.handleRequest(FileUploadHandler.java:290) [vaadin-server-8.1.0.jar:8.1.0]
    at com.vaadin.server.VaadinService.handleRequest(VaadinService.java:1568) [vaadin-server-8.1.0.jar:8.1.0]
    at com.vaadin.server.VaadinServlet.service(VaadinServlet.java:381) [vaadin-server-8.1.0.jar:8.1.0]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:742) [tomcat-embed-core-8.5.16.jar:8.5.16]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) [tomcat-embed-core-8.5.16.jar:8.5.16]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-8.5.16.jar:8.5.16]
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) [tomcat-embed-websocket-8.5.16.jar:8.5.16]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-8.5.16.jar:8.5.16]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-8.5.16.jar:8.5.16]
    at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) [spring-web-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-8.5.16.jar:8.5.16]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-8.5.16.jar:8.5.16]
    at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:105) [spring-web-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-8.5.16.jar:8.5.16]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-8.5.16.jar:8.5.16]
    at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:81) [spring-web-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-8.5.16.jar:8.5.16]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-8.5.16.jar:8.5.16]
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197) [spring-web-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-8.5.16.jar:8.5.16]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-8.5.16.jar:8.5.16]
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198) [tomcat-embed-core-8.5.16.jar:8.5.16]
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-8.5.16.jar:8.5.16]
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:478) [tomcat-embed-core-8.5.16.jar:8.5.16]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) [tomcat-embed-core-8.5.16.jar:8.5.16]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:80) [tomcat-embed-core-8.5.16.jar:8.5.16]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) [tomcat-embed-core-8.5.16.jar:8.5.16]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342) [tomcat-embed-core-8.5.16.jar:8.5.16]
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:799) [tomcat-embed-core-8.5.16.jar:8.5.16]
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-8.5.16.jar:8.5.16]
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) [tomcat-embed-core-8.5.16.jar:8.5.16]
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1455) [tomcat-embed-core-8.5.16.jar:8.5.16]
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-8.5.16.jar:8.5.16]
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [na:1.8.0_111]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [na:1.8.0_111]
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-8.5.16.jar:8.5.16]
    at java.lang.Thread.run(Thread.java:745) [na:1.8.0_111]
Caused by: com.vaadin.server.NoOutputStreamException: null
    at com.vaadin.server.communication.FileUploadHandler.streamToReceiver(FileUploadHandler.java:559) [vaadin-server-8.1.0.jar:8.1.0]
    ... 43 common frames omitted

Answer 1

确保您的应用程序可以在目录/private/var/...中创建文件。最有可能的是，它不可能。我对Vaadin一无所知，但文件夹本身可能是一个只读的＃34; /＆＃34;临时＆＃34;用于存储应用程序所需的解压缩类和数据的目录。此目录可能无意存储任何上传和动态内容。

documentation州：

返回上下文基目录。通常，应用程序以具有应用程序目录的方式部署。对于Web应用程序，此目录是Web应用程序的根目录。在某些情况下，应用程序可能没有应用程序目录（例如在战争中运行的Web应用程序）。

因此，它甚至可能是null，这也会破坏您的代码。

恕我直言，最好使用另一个专用目录进行上传，可以通过应用程序配置指定。或者使用知名的位置，例如/tmp。

另外，请确保首先使用file.getParentFile().mkdirs()创建父目录。

Answer 2

根据Vaadin forum，您不应该在Vaadin服务中保存文件，

您应该在app.getContext().getBaseDirectory()

中保存文件

注意：app在哪里com.vaadin.Application

您可以查看Sample哪个检查属性，以防它无法工作：

 // cannot access example directory, possible security issue with
// Application Server or Servlet Container
// Try to read sample directory from web.xml parameter
if (application.getProperty("sampleDirectory") != null) {
                file = new File(application.getProperty("sampleDirectory"));
                if ((file != null) && (file.canRead())
                        && (file.getAbsolutePath() != null)) {
                    // Success using property
                    return file;
                }

Answer 3

您的文件夹没有权限，请尝试授予/tmp

之类的完整权限

drwxrwxrwt  15 root root 4.0K Nov  4 20:23 tmp

使用sudo chmod 777 /opt/myapp/input_files/

之后尝试执行您的代码。

注意：我使用过/ opt / use也可以使用任何其他文件夹，但请记住授予它权限。

如何使用相对于应用程序的文件路径在服务器上创建文件？

3 个答案: