ZipInputStream 不报告读取的*实际*（即压缩）字节

Question

喜欢这个网站！我的问题如下：

我正在读取来自 HTTP“PUT”请求的网络压缩文件。请求标头告诉我 Content-Length 是（比如说）1Mb。以下代码创建 ZipInputStream，并将 zip 内容保存到当前目录中的文件：

ZipInputStream zis = new ZipInputStream(inputStream);
ZipEntry ze;
long totalBytesRead = 0;
while ((ze = zis.getNextEntry()) != null) {
    BufferedOutputStream outStream = new BufferedOutputStream(new FileOutputStream(ze.getName()));
    byte[] buffer = new byte[4096];
    int i;
    while ((i = zis.read(buffer)) != -1) {
        totalBytesRead+=i;
        outStream.write(buffer,0,i);
    } 
    outStream.close();
}
inputStream.close();

说到底，totalBytesRead 大约等于 1.5Mb（取决于文件的压缩，但可以是任何东西！）。我想知道的是，是否有办法找出从原始inputStream 中读取了多少实际字节？ ze.getSize() 和 ze.getCompressedSize() 对于每个压缩条目都返回 -1（即它不知道）。我需要此信息作为进度条，以显示已从网络读取传输的 zip 文件的字节数。

建议？我是否应该将 ZipInputStream 子类化并尝试找出它从包装的 InputStream 中读取了多少字节？

提前致谢！

Answer 1

import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;

/**
 * 
 */

/**
 * @author clint
 * 
 */
public class ByteCountingInputStream extends FilterInputStream {

  public int totalRead = 0;

  /**
   * @param in
   */
  protected ByteCountingInputStream(InputStream in) {
    super(in);
    // TODO Auto-generated constructor stub
  }

  /* (non-Javadoc)
   * @see java.io.FilterInputStream#read()
   */
  @Override
  public int read() throws IOException {
    int ret = super.read();
    totalRead++;
    return ret;
  }

  /* (non-Javadoc)
   * @see java.io.FilterInputStream#read(byte[], int, int)
   */
  @Override
  public int read(byte[] b, int off, int len) throws IOException {
    int ret = super.read(b, off, len);
    totalRead += ret;
    return ret;
  }

  /* (non-Javadoc)
   * @see java.io.FilterInputStream#read(byte[])
   */
  @Override
  public int read(byte[] b) throws IOException {
    int ret = super.read(b);
    totalRead += ret;
    return ret;
  }

  /* (non-Javadoc)
   * @see java.io.FilterInputStream#skip(long)
   */
  @Override
  public long skip(long n) throws IOException {
    //What to do?
    return super.skip(n);
  }

  /**
   * @return the totalRead
   */
  protected int getTotalRead() {
    return this.totalRead;
  }

}

这介于两者之间

ZipInputStream zis = new ZipInputStream(new ByteCountingInputStream(inputStream));

Answer 2

谢谢你们！我刚刚完全按照克林特的建议完成了！

import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;

public class CountingInputStream extends FilterInputStream {

    private long totalBytes = 0;

    protected CountingInputStream(InputStream in) {
        super(in);
    }

    public int getTotalBytesRead() {
        return totalBytes;
    }

    @Override
    public int read() throws IOException {
        int byteValue = super.read();
        if (byteValue != -1) totalBytes++;
        return byteValue;
    }

    @Override
    public int read(byte[] b) throws IOException {
        int bytesRead = super.read(b);
        if (bytesRead != -1) totalBytes+=bytesRead;
        return bytesRead;
    }

    @Override
    public int read(byte[] b, int off, int len) throws IOException {
        int bytesRead = super.read(b,off,len);
        if (bytesRead != -1) totalBytes+=bytesRead;
        return bytesRead;
    }
}

现在我想知道我应该给谁打个小“复选标记”给...？

再次感谢！

Answer 3

当然，这似乎是合理的。

基本上有两种选择：读取所有字节，将它们存储（在内存或文件中），计算它们，然后解压缩它们；或者在它们进入时对其进行计数。前者似乎效率低下，后者将需要InputStream 的子类，它能够计算它读取的字节数。我想不出标准库中的一个，但那里可能存在实现 - 再说一遍，编写自己的也很容易。

Answer 4

这就是我所做的……不需要覆盖任何东西。

ZipInputStream zis = new ZipInputStream(inputStream);
ZipEntry ze;
int totalBytes = inputStream.available();
int totalBytesRead = 0;
while ((ze = zis.getNextEntry()) != null) {
    totalBytesRead = totalBytes - inputStream.available();
    BufferedOutputStream outStream = new BufferedOutputStream(new FileOutputStream(ze.getName()));
    byte[] buffer = new byte[4096];
    int i;
    while ((i = zis.read(buffer)) != -1) {
        outStream.write(buffer,0,i);
    } 
    outStream.close();
}
inputStream.close();