Struts2文件下载权限被拒绝

Question

我有一个运行在Tomcat 7服务器上的Struts2 web应用程序。我想要做的是让用户从服务器上下载文件。

运行Eclipse Tomcat服务器并访问本地主机时，我没有下载文件的问题。

然而，当我部署到我的服务器，下载链接点击的时候，我得到了以下异常：

java.io.FileNotFoundException: /var/tmp/myFile.pdf (Permission denied) 
    java.io.FileInputStream.open(Native Method) 
    java.io.FileInputStream.<init>(FileInputStream.java:146) 
    com.my.path.to.action.UpdateAction.execute(UpdateAction.java:201) 
    sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
    sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) 
    sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
    java.lang.reflect.Method.invoke(Method.java:606) 
    com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:446) 
    com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:285) 
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248) 
    org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:256) 
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:242) 
    com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:176) 
    com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) 
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:242) 
    com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:265) 
    org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:68) 
    com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) 
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:242) 
    com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:138) 
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:242) 
    com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:238) 
    com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) 
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:242) 
    com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:238) 
    com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) 
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:242) 
    com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:191) 
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:242) 
    org.apache.struts2.interceptor.MultiselectInterceptor.intercept(MultiselectInterceptor.java:73) 
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:242) 
    org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:91) 
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:242) 
    org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:252) 
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:242) 
    com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:100) 
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:242) 
    com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:141) 
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:242) 
    com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:145) 
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:242) 
    com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:171) 
    com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) 
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:242) 
    com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:176) 
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:242) 
    org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:164) 
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:242) 
    com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:193) 
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:242) 
    com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:187) 
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:242) 
    org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:54) 
    org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:544) 
    org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:77) 
    org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:91) 

这里是我的动作要下载的文件

Action.java

private InputStream fileInputStream; 

    public InputStream getFileInputStream() { 
     return fileInputStream; 
    } 

public String execute() throws Exception { 
     File fileToDownload = new File("/var/tmp/myFile.pdf"); 
     System.out.print(fileToDownload.getName()); 
     fileName = fileToDownload.getName(); 
     contentLength = fileToDownload.length(); 
     fileInputStream = new FileInputStream(fileToDownload); 
     return SUCCESS; 
    } 

我已检查过该文件以确保该文件存在于指定的位置，并且确实存在。我也输入了一个不正确的文件名，我得到一个错误，说它找不到指定的文件（这意味着它可以读取目录并确定它不存在。）

这是我的支柱。

struts.xml的

<action name="download" class="com.my.path.to.action.UpdateAction"> 
     <result name="success" type="stream"> 
       <param name="contentDisposition">attachment;filename=${fileName}</param> 
       <param name="contentType">application/doc</param> 
       <param name="inputName">fileInputStream</param> 
       <param name="bufferSize">4096</param> 
       <param name="contentLength">${contentLength}</param> 
     </result> 
</action> 

要确保没有人是迷茫的，我也明显改变，其中的文件是Windows路径（工作）之间的访问路径和Linux的路径（这没有）。

此外，服务器运行在Ubuntu 12.04服务器上。如果这个问题应该转移到另一个论坛上，请让我知道。

Answer 1

这是一个Linux权限问题。您的Tomcat服务器以系统用户身份运行。该用户无权访问路径/var/tmp/。您需要系统管理员来确定运行Tomcat的用户，然后提供对/ var/tmp的访问。而且，是的，这个问题不是Java问题，而是一个系统问题。