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：

我正在读取一个来自HTTP“PUT”请求通过网络传输的zip文件。请求标头告诉我Content-Length是（例如）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();

完成所有操作后，totalBytesRead等于大约1.5Mb（取决于文件的压缩，可能是任何东西！）。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数？对于每个压缩条目，ze.getSize()和ze.getCompressedSize()都返回-1（即它不知道）。我需要这个信息用于进度条，以显示已从网络读取传输的zip文件的字节数。

连连呢？我是否应该继承ZipInputStream并尝试找出它从包装的InputStream读取的字节数？

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;
  }

}

介于

之间

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

Answer 2

谢谢你们俩！我刚刚完成了克林特建议的完全准备工作！

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这个小小的“勾选标记”......？

再次感谢！

Answer 3

当然，这似乎是合理的。

基本上有两个选项：读取所有字节，存储它们（在内存或文件中），计算它们，然后解压缩它们;或者在他们进来时对它们进行计数。前者似乎效率低下，而后者需要InputStream的子类，它能够计算它读取的字节数。我无法想到标准库中的一个，但实现可能存在于那里 - 然后再次编写自己的很容易。

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();