java.io.FileNotFoundException (无此类文件或目录)-下载文件

Question

我有网络应用程序托管在Linux上，包含上传.rar文件的页面和下载它的另一个页面。对于上传功能工作正常，文件上传到服务器成功，但对于下载，它给了我以下异常：

 [servelt.scriptdownloadservelt] in context with path [/OSS-CPE-Tracker] threw exception
  java.io.FileNotFoundException: \usr\local\apache-tomcat-8.5.31\OSS-CPE-Tracker\Zaky\QCAM.rar (No such file or directory)

我使用下面的函数进行上传：

String destDir = "/usr/local/apache-tomcat-8.5.31/OSS-CPE-Tracker/Zaky";
            for (FileItem item : multiparts) {
                if (!item.isFormField()) {
                    String name = new File(item.getName()).getName();
                    if(name.equalsIgnoreCase("QCAM.rar")) {
                                                
                    File destFile = new File(destDir, "QCAM.rar");
                    if (destFile.exists()) {
                        destFile.delete();
                    }
                    item.write(new File("/usr/local/apache-tomcat-8.5.31/OSS-CPE-Tracker/Zaky" + File.separator + name));
                    request.setAttribute("gurumessage", "File Uploaded Successfully");

                }else {
                    request.setAttribute("gurumessage", "Kindly use the agreed name");

                }

这里的下载函数出现了我面临的问题和上面的异常情况：

response.setContentType("text/html");
    PrintWriter out = response.getWriter();
    String gurufile = "QCAM.rar\\";
    String gurupath = "\\usr\\local\\apache-tomcat-8.5.31\\OSS-CPE-Tracker\\Zaky";

    
    response.setContentType("APPLICATION/OCTET-STREAM");
    response.setHeader("Content-Disposition", "attachment; filename=\""
            + gurufile + "\"");

    FileInputStream fileInputStream = new FileInputStream(gurupath
            + gurufile);

    int i;
    while ((i = fileInputStream.read()) != -1) {
        out.write(i);
    }
    fileInputStream.close();
    out.close();

Answer 1

出现此错误的唯一原因是在该路径下找不到文件。

请验证路径

    String gurufile = "QCAM.rar\\";
    String gurupath = "\\usr\\local\\apache-tomcat-8.5.31\\OSS-CPE-Tracker\\Zaky";
    // <...>
    FileInputStream fileInputStream = new FileInputStream(gurupath
            + gurufile);

在unix系统中，使用正斜杠/而不是反斜杠\解析文件路径。

尝试更改为与upload脚本相同的值：

    FileInputStream fileInputStream = new FileInputStream("/usr/local/apache-tomcat-8.5.31/OSS-CPE-Tracker/Zaky/QCAM.rar")

这应该可以了。