java.io.filenotfoundexception downloading zip and extracting it

问题

I made a small program to download a zip file from a direct link and after that extract all contents of it in the same directory. It doesn't download anything and it also doesn't extract. This is what I have so far:

package main;

import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.net.URL;
import java.nio.channels.Channels;
import java.nio.channels.ReadableByteChannel;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;

public class Main {

    static String url = "https://www.dropbox.com/s/uml938guklfvo7r/Tekst.zip?dl=1";
    static int lastSlashIndex = url.lastIndexOf('/');
    static String filename= url.substring(lastSlashIndex + 1, url.length() - 5);
    static String filepath = "C:";
    private static final int BUFFER = 4096;

    public static void main(String[] args) {

        try{
            URL website = new URL(url);
            ReadableByteChannel rbc;
            rbc = Channels.newChannel(website.openStream());
            new File(filepath + filename).createNewFile();
            FileOutputStream fos = new FileOutputStream(filepath + filename);
            fos.getChannel().transferFrom(rbc, 0, Long.MAX_VALUE);
            fos.close();
        }catch(Exception e){ e.printStackTrace(); }

        try {
            unzip(filepath + filename, filepath);
        } catch (IOException e) {
            e.printStackTrace();
        }


    }

    public static void unzip(String zipFilePath, String destDirectory) throws IOException {
        File destDir = new File(destDirectory);
        if (!destDir.exists()) {
            destDir.mkdir();
        }
        ZipInputStream zipIn = new ZipInputStream(new FileInputStream(zipFilePath));
        ZipEntry entry = zipIn.getNextEntry();
        // iterates over entries in the zip file
        while (entry != null) {
            String filePath = destDirectory + File.separator + entry.getName();
            if (!entry.isDirectory()) {
                // if the entry is a file, extracts it
                extractFile(zipIn, filePath);
            } else {
                // if the entry is a directory, make the directory
                File dir = new File(filePath);
                dir.mkdir();
            }
            zipIn.closeEntry();
            entry = zipIn.getNextEntry();
        }
        zipIn.close();
    }

    private static void extractFile(ZipInputStream zipIn, String filePath) throws IOException {
        Line 68>> BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(filePath));
        byte[] bytesIn = new byte[BUFFER];
        int read = 0;
        while ((read = zipIn.read(bytesIn)) != -1) {
            bos.write(bytesIn, 0, read);
        }
        bos.close();
    }  
}

Here is the error:

java.io.FileNotFoundException: C:\Tekst.txt (Access is denied)
    at java.io.FileOutputStream.open(Native Method)
    at java.io.FileOutputStream.<init>(Unknown Source)
    at java.io.FileOutputStream.<init>(Unknown Source)
    at main.Main.extractFile(Main.java:68)
    at main.Main.unzip(Main.java:55)
    at main.Main.main(Main.java:35)

回答1:

Apparently this file is simply not created yet. You can create it with

new File(yourFilepath).createNewFile()

and you need to do it before you invoke

FileOutputStream fos = new FileOutputStream(filepath + filename);

which throws the exception. Then it works perfectly fine.

来源：https://stackoverflow.com/questions/29103251/java-io-filenotfoundexception-downloading-zip-and-extracting-it

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