Java IOException - 使用 FileOutputStream 拒绝访问

IOException - Access Denied Using FileOutputStream

提问by David Castle

I get the following IOException :

我得到以下 IOException ：

java.io.IOException: Access is denied
 at java.io.WinNTFileSystem.createFileExclusively(Native Method)
 at java.io.File.createNewFile(File.java:850)
 at zipUnzipper.main(zipUnzipper.java:41)

When trying to run the following piece of code :

尝试运行以下代码时：

public class zipUnzipper {
    public zipUnzipper() {
    }

    public static void main(String[] args){

        //Unzip to temp folder. Add all files to mFiles. Print names of all files in mFfiles.
        File file = new File("C:\aZipFile.zip");
        String  filename = file.getName();
        String filePathName = new String();

        int o = filename.lastIndexOf('.');
            filename = filename.substring(0,o);

        try {      
                ZipFile zipFile = new ZipFile (file.getAbsoluteFile());
                Enumeration entries = zipFile.entries();
                while(entries.hasMoreElements()) {
                    ZipEntry zipEntry = (ZipEntry) entries.nextElement();
                    System.out.println("Unzipping: " + zipEntry.getName());
                    BufferedInputStream bis = new BufferedInputStream(zipFile.getInputStream(zipEntry));
                    byte[] buffer = new byte[2048];
                    filePathName = "C:\TEMP\"+filename+"\";
                    File fileToWrite = new File(filePathName+ zipEntry.getName());
                    fileToWrite.mkdirs();
                    fileToWrite.createNewFile();
                    FileOutputStream fos = new FileOutputStream(fileToWrite);
                    BufferedOutputStream bos = new BufferedOutputStream( fos , buffer.length );
                    int size;
                    while ((size = bis.read(buffer, 0, buffer.length)) != -1) {
                        bos.write(buffer, 0, size);
                    }
                    bos.flush();
                    bos.close();
                    bis.close();
                }
                zipFile.close();
                File folder = new File (filePathName);
                File [] mFiles = folder.listFiles();

                for (int x=0; x<mFiles.length; x++) {
                                System.out.println(mFiles[x].getAbsolutePath());
                        }
        } catch (ZipException ze) {
            ze.printStackTrace();
        } catch (IOException ioe) {
            ioe.printStackTrace();
        }

    }
}

It seems to me that for some reason the JVM can't create a new file. The code runs perfectly well if the files already exist. Is there some kind of access file which dictates whether the JVM can create a new file or am I simply doing something wrong?

在我看来，由于某种原因，JVM 无法创建新文件。如果文件已经存在，代码运行得很好。是否有某种访问文件指示 JVM 是否可以创建新文件，或者我只是做错了什么？

Any help is much appreciated :-)

任何帮助深表感谢 ：-）

I'm running Java 1.4 and have been testing in JDeveloper in Windows XP.

我正在运行 Java 1.4，并且一直在 Windows XP 中的 JDeveloper 中进行测试。

采纳答案by juancn

The issue is that these calls step on each other:

问题是这些调用相互影响：

  fileToWrite.mkdirs(); //creates a directory e.g. C:\temp\foo\x
  fileToWrite.createNewFile(); //attempts to create a file C:\temp\foo\x

The create operation fails because you just created a directory with the same name than the file you want to create.

创建操作失败，因为您刚刚创建了一个与要创建的文件同名的目录。

What you want to do instead is:

你想要做的是：

fileToWrite.getParentFile().mkdirs()

fileToWrite.getParentFile().mkdirs()

And also, the call to createNewFile()is unnecessary.

而且，调用createNewFile()是不必要的。

Based on your code. The following "unzips" a zip file:

根据您的代码。以下“解压缩”一个 zip 文件：

import java.io.*;
import java.util.zip.ZipFile;
import java.util.zip.ZipEntry;
import java.util.Enumeration;

public class Unzipper {
    public static void main(String[] args)
            throws IOException {
        final File file = new File(args[0]);
        final ZipFile zipFile = new ZipFile(file);
        final byte[] buffer = new byte[2048];
        final File tmpDir = new File(System.getProperty("java.io.tmpdir"), zipFile.getName());

        if(!tmpDir.mkdir() && tmpDir.exists()) {
            System.err.println("Cannot create: " + tmpDir);
            System.exit(0);
        }

        for(final Enumeration entries = zipFile.entries(); entries.hasMoreElements();) {
            final ZipEntry zipEntry = (ZipEntry) entries.nextElement();
            System.out.println("Unzipping: " + zipEntry.getName());

            final InputStream is = zipFile.getInputStream(zipEntry);
            final File fileToWrite = new File(tmpDir, zipEntry.getName());
            final File folder = fileToWrite.getParentFile();
            if(!folder.mkdirs() && !folder.exists()) {
                System.err.println("Cannot create: " + folder);
                System.exit(0);
            }

            if(!zipEntry.isDirectory()) {
                //No need to use buffered streams since we're doing our own buffering
                final FileOutputStream fos = new FileOutputStream(fileToWrite);
                int size;
                while ((size = is.read(buffer)) != -1) {
                    fos.write(buffer, 0, size);
                }
                fos.close();
                is.close();
            }
        }
        zipFile.close();
    }
}

Disclaimer: I haven't tested it beyond the very basics.

免责声明：我还没有对它进行非常基础的测试。

回答by Jonathan Feinberg

Why are you calling createNewFile()? Just create the FileOutputStream.

你为什么打电话createNewFile()？只需创建 FileOutputStream。

回答by Gangnus

It also could be that in context where you are launching the application you haven't access rights to the place where you are trying to create the file. Launch the app as admin or create the file in the project folder.

也可能是在您启动应用程序的上下文中，您无权访问您尝试创建文件的位置。以管理员身份启动应用程序或在项目文件夹中创建文件。