Bz2文件

Question

我试图从维基百科上获取一些bz2文件，我不在乎它们是保存为bz2还是解压缩，因为我可以在本地解压缩它们。

当我打电话：

public static void getZip(String theUrl, String filename) throws IOException {
    URL gotoUrl = new URL(theUrl);
    try (InputStreamReader isr = new InputStreamReader(new BZip2CompressorInputStream(gotoUrl.openStream())); BufferedReader in = new BufferedReader(isr)) {
        StringBuffer sb = new StringBuffer();
        String inputLine;

        // grab the contents at the URL
        while ((inputLine = in.readLine()) != null) {
            sb.append(inputLine + "\r\n");
        }
        // write it locally
        Wget.createAFile(filename, sb.toString());
    } catch (MalformedURLException mue) {
        mue.printStackTrace();
    } catch (IOException ioe) {
        throw ioe;
    }
}

我得到了解压缩文件的一部分，不超过+- 883 K。

当我不使用BZip2CompressorInputStream时，比如：

public static void get(String theUrl, String filename) throws IOException {
    try {
        URL gotoUrl = new URL(theUrl);
        InputStreamReader isr = new InputStreamReader(gotoUrl.openStream());
        BufferedReader in = new BufferedReader(isr);

        StringBuffer sb = new StringBuffer();
        String inputLine;

        // grab the contents at the URL
        while ((inputLine = in.readLine()) != null) {
            sb.append(inputLine);// + "\r\n");
        }
        // write it locally
        Statics.writeOut(filename, false, sb.toString());
    } catch (MalformedURLException mue) {
        mue.printStackTrace();
    } catch (IOException ioe) {
        throw ioe;
    }
}

我得到了一个文件，其大小与它所设想的大小相同(与KB而不是B相比)。但是还有一条消息，即压缩文件已经损坏，在使用byte []而不是readLine()时也是如此，如下所示：

public static void getBytes(String theUrl, String filename) throws IOException {
    try {
        char [] cc = new char[1024];
        URL gotoUrl = new URL(theUrl);
        InputStreamReader isr = new InputStreamReader(gotoUrl.openStream());
        BufferedReader in = new BufferedReader(isr);

        StringBuffer sb = new StringBuffer();
        // grab the contents at the URL
        int n = 0;
        while (-1 != (n = in.read(cc))) {
            sb.append(cc);// + "\r\n");
        }
        // write it locally
        Statics.writeOut(filename, false, sb.toString());
    } catch (MalformedURLException mue) {
        mue.printStackTrace();
    } catch (IOException ioe) {
        throw ioe;
    }
}

最后，当我bzip2 inputstream和outputstream时，我得到一个有效的bzip2文件，但是大小类似于第一个文件，使用：

public static void getWriteForBZ2File(String urlIn, final String filename) throws CompressorException, IOException {
    URL gotoUrl = new URL(urlIn);
    try (final FileOutputStream out = new FileOutputStream(filename);
            final BZip2CompressorOutputStream dataOutputStream = new BZip2CompressorOutputStream(out);
            final BufferedInputStream bis = new BufferedInputStream(gotoUrl.openStream());
            final CompressorInputStream input = new CompressorStreamFactory().createCompressorInputStream(bis);
            final BufferedReader br2 = new BufferedReader(new InputStreamReader(input))) {
        String line = null;
        while ((line = br2.readLine()) != null) {
            dataOutputStream.write(line.getBytes());
        }
    }
}

那么，如何以bz2格式或解压缩方式获得整个bz2文件呢？

Answer 1

bz2文件包含字节，而不是字符。你不能把它当作包含字符的读取器来阅读。

由于您只想下载文件并将其保存在本地，所以您所需要的就是

Files.copy(gotoUrl.openStream(), Paths.get(fileName));