IOException-使用FileOutputStream拒绝访问

Z时代
2024-01-10
分类：问答

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)

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();
        }
    }
}

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，则代码可以很好地运行。是否存在某种访问文件来指示JVM是否可以创建新文件还是我只是在做错什么？

任何帮助深表感谢：-）

我正在运行Java 1.4，并且已经在Windows XP中的JDeveloper中进行了测试。

回答：

问题在于这些调用彼此接替：

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

创建操作失败，因为您刚刚创建的目录名与要创建的文件相同。

您要执行的操作是：

fileToWrite.getParentFile().mkdirs()

而且，createNewFile()没有必要拨打电话。

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();
    }
}