java - Struts2 文件下载权限被拒绝

Question

我有一个在 Tomcat 7 服务器上运行的 Struts2 webapp。我想要做的是允许用户从服务器下载文件。

运行 Eclipse Tomcat 服务器并访问本地主机时，下载文件没有问题。

但是，当我部署到我的服务器上时，单击下载链接时，出现以下异常:

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)

这是我下载文件的 Action

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;
    }

我已经检查了该文件以确保该文件存在于指定位置并且它确实存在。我也输入了一个错误的文件名，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

<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>

为了确保没有人感到困惑，我显然在 Windows 路径(有效)和 Linux 路径(无效)之间更改了访问文件的路径。

此外，该服务器在 Ubuntu 12.04 服务器上运行。如果这个问题应该转移到不同的论坛，请告诉我。

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。此用户没有路径 /var/tmp/ 的权限。您需要系统管理员来确定运行 Tomcat 的用户，然后提供对/var/tmp 的访问权限。而且，是的，这个问题不是 Java 问题，而是系统问题。