Question

我有一个应用程序使用JLayer / BasicPlayer库通过HTTP播放远程MP3文件。我想将播放的mp3文件保存到磁盘而不重新下载。

这是使用基于JLayer的BasicPlayer播放MP3文件的代码。

String mp3Url = "http://ia600402.us.archive.org/6/items/Stockfinster.-DeadLinesutemos025/01_Push_Push.mp3";
URL url = new URL(mp3Url);
URLConnection conn = url.openConnection();
InputStream is = conn.getInputStream();
BufferedInputStream bis = new BufferedInputStream(is);

BasicPlayer player = new BasicPlayer();
player.open(bis);
player.play();

如何将mp3文件保存到磁盘？

Answer 1

为了避免必须经历两次字节，您需要将连接中的输入流包装在一个过滤器中，该过滤器将读取的任何数据写入输出流，即一种“T形管道输入流”。这样的类并不难写，但您可以使用Apache Commons IO库中的TeeInputStream来保存工作。

Apache Commons IO：http://commons.apache.org/io/
TeeInputStream javadoc：http://commons.apache.org/io/apidocs/org/apache/commons/io/input/TeeInputStream.html

编辑：概念验证：

import java.io.*;

public class TeeInputStream extends InputStream {
    private InputStream in;
    private OutputStream out;

    public TeeInputStream(InputStream in, OutputStream branch) {
        this.in=in;
        this.out=branch;
    }
    public int read() throws IOException {
        int read = in.read();
        if (read != -1) out.write(read);
        return read;
    }
    public void close() throws IOException {
        in.close();
        out.close();
    }
}

如何使用它：

...
BufferedInputStream bis = new BufferedInputStream(is);
TeeInputStream tis = new TeeInputStream(bis,new FileOutputStream("test.mp3"));

BasicPlayer player = new BasicPlayer();
player.open(tis);
player.play();

Answer 2

BufferedInputStream in = new BufferedInputStream(is);

OutputStream out = new BufferedOutputStream(new FileOutputStream(new File(savePathAndFilename)));  
    byte[] buf = new byte[256];  
    int n = 0;  
    while ((n=in.read(buf))>=0) {  
       out.write(buf, 0, n);  
    }  
    out.flush();  
    out.close();

Answer 3

您可以先使用FileInputStream将流写入磁盘。然后从文件重新加载流。

Answer 4

包裹你自己的InputStream

class myInputStream extends InputStream {

    private InputStream is;
    private FileOutputStream resFile;
    public myInputStream(InputStream is) throws FileNotFoundException {
        this.is = is;
        resFile = new FileOutputStream("path_to_result_file");
    }

    @Override
    public int read() throws IOException {
        int b = is.read();
        if (b != -1)
            resFile.write(b);
        return b;
    }

    @Override
    public void close() {
        try {
            resFile.close();
        } catch (IOException ex) {
        }
        try {
            is.close();
        } catch (IOException ex) {
        }
    }
}

并使用

InputStream is = conn.getInputStream();
myInputStream myIs = new myInputStream(is);
BufferedInputStream bis = new BufferedInputStream(myIs);

在Java中播放时将mp3文件写入磁盘

4 个答案: