5

如何将文件附加到现有的 zip 文件?我已经有了可以创建 zip 文件的代码,除了一个大问题外,它工作得很好。它现在的工作方式是,用户拍摄一堆照片,最后,所有照片都被添加到一个 zip 文件中,如果你拍摄足够多的照片,这可能需要相当长的时间。:-( 所以我在想,我有一个非常好的和有效的解决方案。拍摄照片时,我会在拍摄后立即将每张新照片添加到 zip 文件中。然后当他们完成拍照时,完成 zip 文件,使其可用并导出。:-)

问题是,我无法将文件添加到现有的 zip 文件中。:-( 这是我到目前为止所拥有的。另外,请记住,这只是一个概念证明,我知道为 for 循环的每次迭代重新初始化所有内容是非常愚蠢的。循环的每次迭代都是应该代表正在添加的另一个文件,这很可能会在很长一段时间后,甚至可能是一个小时后,这就是为什么我每次迭代都会重置所有内容,因为应用程序将在添加文件之间关闭。如果我能让这个工作,然后我实际上会放弃 for 循环并将此代码放入一个函数中,该函数在每次拍摄照片时都会被调用。:-)

        try  {
            for(int i=0; i < _files.size(); i++) {
                //beginning of initial setup stuff
                BufferedInputStream origin = null;
                FileOutputStream dest = new FileOutputStream(_zipFile,false); 
                ZipOutputStream out = new ZipOutputStream(new BufferedOutputStream(dest));
                byte data[] = new byte[BUFFER];
                out.setLevel(0); //I added this because it makes it not compress the data 
                //at all and I hoped that it would allow the zip to be appended to
                //end of initial setup stuff

                //beginning of old for loop
                Log.v("Compress", "Adding: " + _files[i]); 
                FileInputStream fi = new FileInputStream(_files[i]); 
                origin = new BufferedInputStream(fi, BUFFER); 
                ZipEntry entry = new ZipEntry(_files[i].substring(_files[i].lastIndexOf("/") + 1)); 
                out.putNextEntry(entry); 
                int count; 
                while ((count = origin.read(data, 0, BUFFER)) != -1) { 
                    out.write(data, 0, count); 
                } 
                origin.close();     
                //end of for old loop

                //beginning of finishing stuff
                out.close();
                //end of finishing stuff
            } 
        } catch(Exception e) {
            Log.e("ZipCreation", "Error writing zip", e);
            e.printStackTrace();
        }

另外,我已经尝试过

FileOutputStream dest = new FileOutputStream(_zipFile,true);

如果您注意到,我将 append 设置为 true,这实际上会将数据附加到现有文件中。有趣的是,它实际上确实将数据附加到原始文件中,但是,在我的计算机上提取文件后,最后写入的文件就是所有被提取的文件,这很糟糕。:-( 那么有什么方法可以开始编写一个 zip 文件,然后再添加它,然后完成 zip 文件?我什至考虑过可能采用 ZipOutputStream 并对其进行修改以适应我需要的这个模型. 它应该以某种方式在逻辑上是可能的?:-)

在此先感谢您的帮助!:-D

-贾里德

4

2 回答 2

2

好的,感谢您的所有建议,但我能够让它像我想要的那样工作......它可以完成,您可以在关闭文件后添加文件,只要您保存您的位置!:-D

以下是我如何让它开始工作:

        try  {
            for(int i=0; i < _files.size(); i++) {
                //beginning of initial setup stuff
                BufferedInputStream origin = null;
                FileOutputStream dest = new FileOutputStream(_zipFile,true); 
                ZipOutputStreamNew out = new ZipOutputStreamNew(new BufferedOutputStream(dest));
                byte data[] = new byte[BUFFER];
                if (havePreviousData) {
                    out.setWritten(tempWritten);
                    out.setXentries(tempXentries);
                }
                //end of initial setup stuff

                //beginning of for loop
                Log.i("Compress", "Adding: " + _files.get(i));
                FileInputStream fi = new FileInputStream(_files.get(i)); 
                origin = new BufferedInputStream(fi, BUFFER);
                TempString = _files.get(i).substring(_files.get(i).lastIndexOf("/") + 1);
                ZipEntry entry = new ZipEntry(_paths.get(i) + TempString);
                out.putNextEntry(entry);
                int count;
                while ((count = origin.read(data, 0, BUFFER)) != -1) { 
                    out.write(data, 0, count); 
                }
                origin.close();
                out.closeEntry();
                //end of for loop

                //beginning of finishing stuff
                if (i == (_files.size()-1)) {
                    //it's the last record so we should finish it off
                    out.closeAndFinish();
                } else {
                    //close the file, but don't write the Central Directory
                    //first, back up where the zip file was...
                    tempWritten = out.getWritten();
                    tempXentries = out.getXentries();
                    havePreviousData = true;
                    //now close the file
                    out.close();
                }
                //end of finishing stuff
            }
            //zip succeeded
    } catch(Exception e) {
        Log.e("ZipCreation", "Error writing zip", e);
        e.printStackTrace();
    }

另外,请记住,这不是我必须做的唯一代码。我还必须制作自己的 ZipOutputStream 副本,以便公开我在 ZipOutputStreamNew 类中创建的以下函数......

getWritten()
getXentries()

setWritten(long mWritten)
setXentries(Vector<XEntry> mXEntries)

在大多数情况下,所有这一切都是开始正常写入,然后不是正常关闭,而是备份这两个变量,然后在下一次迭代中,它只恢复这些变量。

如果您对这一切有任何疑问,请告诉我,但我知道它会起作用,它所要做的就是保存它所在的位置。:-D

再次感谢大家的帮助!:-)

应 Raj 的要求,这里是 ZipOutputStreamNew 的源代码:

/**
 * This class implements an output stream filter for writing files in the
 * ZIP file format. Includes support for both compressed and uncompressed
 * entries.
 *
 * @author  David Connelly
 * @version %I%, %G%
 */
public class ZipOutputStreamNew extends DeflaterOutputStream implements ZipConstants {
    public static class XEntry {
        public final ZipEntry entry;
        public final long offset;
        public final int flag;
        public XEntry(ZipEntry entry, long offset) {
            this.entry = entry;
            this.offset = offset;
            this.flag = (entry.getMethod() == DEFLATED &&
                 (entry.getSize() == -1 ||
                  entry.getCompressedSize() == -1 ||
                  entry.getCrc() == -1))
            // store size, compressed size, and crc-32 in data descriptor
            // immediately following the compressed entry data
            ? 8
            // store size, compressed size, and crc-32 in LOC header
            : 0;
        }
    }

    private XEntry current;
    private Vector<XEntry> xentries = new Vector<XEntry>();
    private HashSet<String> names = new HashSet<String>();
    private CRC32 crc = new CRC32();
    private long written = 0;
    private long locoff = 0;
    private String comment;
    private int method = DEFLATED;
    private boolean finished;

    private boolean closed = false;
    private boolean closeItPermanently = false;

    private static int version(ZipEntry e) throws ZipException {
    switch (e.getMethod()) {
    case DEFLATED: return 20;
    case STORED:   return 10;
    default: throw new ZipException("unsupported compression method");
    }
    }

    /**
     * Checks to make sure that this stream has not been closed.
     */
    private void ensureOpen() throws IOException {
    if (closed) {
        throw new IOException("Stream closed");
        }
    }
    /**
     * Compression method for uncompressed (STORED) entries.
     */
    public static final int STORED = ZipEntry.STORED;

    /**
     * Compression method for compressed (DEFLATED) entries.
     */
    public static final int DEFLATED = ZipEntry.DEFLATED;

    /**
     * Creates a new ZIP output stream.
     * @param out the actual output stream
     */
    public ZipOutputStreamNew(OutputStream out) {
    super(out, new Deflater(Deflater.DEFAULT_COMPRESSION, true));
        usesDefaultDeflater = true;
    }

    /**
     * Sets the ZIP file comment.
     * @param comment the comment string
     * @exception IllegalArgumentException if the length of the specified
     *        ZIP file comment is greater than 0xFFFF bytes
     */
    public void setComment(String comment) {
        if (comment != null && comment.length() > 0xffff/3
                                           && getUTF8Length(comment) > 0xffff) {
        throw new IllegalArgumentException("ZIP file comment too long.");
    }
    this.comment = comment;
    }

    /**
     * Sets the default compression method for subsequent entries. This
     * default will be used whenever the compression method is not specified
     * for an individual ZIP file entry, and is initially set to DEFLATED.
     * @param method the default compression method
     * @exception IllegalArgumentException if the specified compression method
     *        is invalid
     */
    public void setMethod(int method) {
    if (method != DEFLATED && method != STORED) {
        throw new IllegalArgumentException("invalid compression method");
    }
    this.method = method;
    }

    /**
     * Sets the compression level for subsequent entries which are DEFLATED.
     * The default setting is DEFAULT_COMPRESSION.
     * @param level the compression level (0-9)
     * @exception IllegalArgumentException if the compression level is invalid
     */
    public void setLevel(int level) {
    def.setLevel(level);
    }

    /**
     * Begins writing a new ZIP file entry and positions the stream to the
     * start of the entry data. Closes the current entry if still active.
     * The default compression method will be used if no compression method
     * was specified for the entry, and the current time will be used if
     * the entry has no set modification time.
     * @param e the ZIP entry to be written
     * @exception ZipException if a ZIP format error has occurred
     * @exception IOException if an I/O error has occurred
     */
    public void putNextEntry(ZipEntry e) throws IOException {
    ensureOpen();
    if (current != null) {
        closeEntry();   // close previous entry
    }
    if (e.getTime() == -1) {
        e.setTime(System.currentTimeMillis());
    }
    if (e.getMethod() == -1) {
        e.setMethod(method);    // use default method
    }
    switch (e.getMethod()) {
    case DEFLATED:
        break;
    case STORED:
        // compressed size, uncompressed size, and crc-32 must all be
        // set for entries using STORED compression method
        if (e.getSize() == -1) {
        e.setSize(e.getCompressedSize());
        } else if (e.getCompressedSize() == -1) {
        e.setCompressedSize(e.getSize());
        } else if (e.getSize() != e.getCompressedSize()) {
        throw new ZipException(
            "STORED entry where compressed != uncompressed size");
        }
        if (e.getSize() == -1 || e.getCrc() == -1) {
        throw new ZipException(
            "STORED entry missing size, compressed size, or crc-32");
        }
        break;
    default:
        throw new ZipException("unsupported compression method");
    }
    if (! names.add(e.getName())) {
        throw new ZipException("duplicate entry: " + e.getName());
    }
    current = new XEntry(e, written);
    xentries.add(current);
        writeLOC(current);
    }

    /**
     * Closes the current ZIP entry and positions the stream for writing
     * the next entry.
     * @exception ZipException if a ZIP format error has occurred
     * @exception IOException if an I/O error has occurred
     */
    public void closeEntry() throws IOException {
    ensureOpen();
    if (current != null) {
        ZipEntry e = current.entry;
        switch (e.getMethod()) {
        case DEFLATED:
        def.finish();
        while (!def.finished()) {
            deflate();
        }
        if ((current.flag & 8) == 0) {
            // verify size, compressed size, and crc-32 settings
            if (e.getSize() != def.getBytesRead()) {
            throw new ZipException(
                "invalid entry size (expected " + e.getSize() +
                " but got " + def.getBytesRead() + " bytes)");
            }
            if (e.getCompressedSize() != def.getBytesWritten()) {
            throw new ZipException(
                "invalid entry compressed size (expected " +
                e.getCompressedSize() + " but got " + def.getBytesWritten() + " bytes)");
            }
            if (e.getCrc() != crc.getValue()) {
            throw new ZipException(
                "invalid entry CRC-32 (expected 0x" +
                Long.toHexString(e.getCrc()) + " but got 0x" +
                Long.toHexString(crc.getValue()) + ")");
            }
        } else {
            e.setSize(def.getBytesRead());
            e.setCompressedSize(def.getBytesWritten());
            e.setCrc(crc.getValue());
            writeEXT(e);
        }
        def.reset();
        written += e.getCompressedSize();
        break;
        case STORED:
        // we already know that both e.size and e.csize are the same
        if (e.getSize() != written - locoff) {
            throw new ZipException(
            "invalid entry size (expected " + e.getSize() +
            " but got " + (written - locoff) + " bytes)");
        }
        if (e.getCrc() != crc.getValue()) {
            throw new ZipException(
             "invalid entry crc-32 (expected 0x" +
             Long.toHexString(e.getCrc()) + " but got 0x" +
             Long.toHexString(crc.getValue()) + ")");
        }
        break;
        default:
        throw new ZipException("invalid compression method");
        }
        crc.reset();
        current = null;
    }
    }

    /**
     * Writes an array of bytes to the current ZIP entry data. This method
     * will block until all the bytes are written.
     * @param b the data to be written
     * @param off the start offset in the data
     * @param len the number of bytes that are written
     * @exception ZipException if a ZIP file error has occurred
     * @exception IOException if an I/O error has occurred
     */
    public synchronized void write(byte[] b, int off, int len)
    throws IOException
    {
    ensureOpen();
        if (off < 0 || len < 0 || off > b.length - len) {
        throw new IndexOutOfBoundsException();
    } else if (len == 0) {
        return;
    }

    if (current == null) {
        throw new ZipException("no current ZIP entry");
    }
    ZipEntry entry = current.entry;
    switch (entry.getMethod()) {
    case DEFLATED:
        super.write(b, off, len);
        break;
    case STORED:
        written += len;
        if (written - locoff > entry.getSize()) {
        throw new ZipException(
            "attempt to write past end of STORED entry");
        }
        out.write(b, off, len);
        break;
    default:
        throw new ZipException("invalid compression method");
    }
    crc.update(b, off, len);
    }

    /**
     * Finishes writing the contents of the ZIP output stream without closing
     * the underlying stream. Use this method when applying multiple filters
     * in succession to the same output stream.
     * @exception ZipException if a ZIP file error has occurred
     * @exception IOException if an I/O exception has occurred
     */
    public void finish() throws IOException {
        ensureOpen();
        if (finished) {
            return;
        }
        if (current != null) {
            closeEntry();
        }
        if (xentries.size() < 1) {
            throw new ZipException("ZIP file must have at least one entry");
        }
        if (closeItPermanently) {
            // write central directory
            long off = written;
            for (XEntry xentry : xentries)
                writeCEN(xentry);
            writeEND(off, written - off);
            finished = true;
            //Log.e("ZipOutputStreamNew", "I just ran wrote the Central Directory Jared!");
        }
        //Log.e("ZipOutputStreamNew", "I just ran finish() Jared!");
    }

    /**
     * Gets the value of the "xentries" variable (for later use)
     * @return
     */
    public Vector<XEntry> getXentries() {
        return xentries;

        //TODO convert this to primitive data types
    }

    /**
     * Gets the value of the "written" variable (for later use)
     * @return
     */
    public long getWritten() {
        return written;
    }


    /**
     * Sets the value of the "xentries" variable (for later use)
     * @return
     */
    public void setXentries(Vector<XEntry> mXEntries) {
        xentries = mXEntries;
        //TODO convert this to primitive data types
    }

    /**
     * Sets the value of the "written" variable (for later use)
     * @return
     */
    public void setWritten(long mWritten) {
        written = mWritten;
    }


    /**
     * Closes the ZIP output stream as well as the stream being filtered.
     * @exception ZipException if a ZIP file error has occurred
     * @exception IOException if an I/O error has occurred
     */
    public void closeAndFinish() throws IOException {
        if (!closed) {
            closeItPermanently=true;
            super.close();
            closed = true;
        }
    }

    /**
     * Used to close the ZIP output stream as well as the stream being filtered.
     * instead it does nothing :-P
     * @exception ZipException if a ZIP file error has occurred
     * @exception IOException if an I/O error has occurred
     */
    public void close() throws IOException {
        if (!closed) {
            closeItPermanently=false;
            super.close();
            closed = true;
        }
    }

    /*
     * Writes local file (LOC) header for specified entry.
     */
    private void writeLOC(XEntry xentry) throws IOException {
    ZipEntry e = xentry.entry;
    int flag = xentry.flag;
    writeInt(LOCSIG);       // LOC header signature
    writeShort(version(e));     // version needed to extract
    writeShort(flag);           // general purpose bit flag
    writeShort(e.getMethod());       // compression method
    writeInt(e.getTime());           // last modification time
    if ((flag & 8) == 8) {
        // store size, uncompressed size, and crc-32 in data descriptor
        // immediately following compressed entry data
        writeInt(0);
        writeInt(0);
        writeInt(0);
    } else {
        writeInt(e.getCrc());        // crc-32
        writeInt(e.getCompressedSize());      // compressed size
        writeInt(e.getSize());       // uncompressed size
    }
    byte[] nameBytes = getUTF8Bytes(e.getName());
    writeShort(nameBytes.length);
    writeShort(e.getExtra() != null ? e.getExtra().length : 0);
    writeBytes(nameBytes, 0, nameBytes.length);
    if (e.getExtra() != null) {
        writeBytes(e.getExtra(), 0, e.getExtra().length);
    }
    locoff = written;
    }

    /*
     * Writes extra data descriptor (EXT) for specified entry.
     */
    private void writeEXT(ZipEntry e) throws IOException {
    writeInt(EXTSIG);       // EXT header signature
    writeInt(e.getCrc());       // crc-32
    writeInt(e.getCompressedSize());        // compressed size
    writeInt(e.getSize());      // uncompressed size
    }

    /*
     * Write central directory (CEN) header for specified entry.
     * REMIND: add support for file attributes
     */
    private void writeCEN(XEntry xentry) throws IOException {
    ZipEntry e  = xentry.entry;
    int flag = xentry.flag;
    int version = version(e);
    writeInt(CENSIG);       // CEN header signature
    writeShort(version);        // version made by
    writeShort(version);        // version needed to extract
    writeShort(flag);       // general purpose bit flag
    writeShort(e.getMethod());      // compression method
    writeInt(e.getTime());      // last modification time
    writeInt(e.getCrc());       // crc-32
    writeInt(e.getCompressedSize());        // compressed size
    writeInt(e.getSize());      // uncompressed size
    byte[] nameBytes = getUTF8Bytes(e.getName());
    writeShort(nameBytes.length);
    writeShort(e.getExtra() != null ? e.getExtra().length : 0);
    byte[] commentBytes;
    if (e.getComment() != null) {
        commentBytes = getUTF8Bytes(e.getComment());
        writeShort(commentBytes.length);
    } else {
        commentBytes = null;
        writeShort(0);
    }
    writeShort(0);          // starting disk number
    writeShort(0);          // internal file attributes (unused)
    writeInt(0);            // external file attributes (unused)
    writeInt(xentry.offset);    // relative offset of local header
    writeBytes(nameBytes, 0, nameBytes.length);
    if (e.getExtra() != null) {
        writeBytes(e.getExtra(), 0, e.getExtra().length);
    }
    if (commentBytes != null) {
        writeBytes(commentBytes, 0, commentBytes.length);
    }
    }

    /*
     * Writes end of central directory (END) header.
     */
    private void writeEND(long off, long len) throws IOException {
    int count = xentries.size();
    writeInt(ENDSIG);       // END record signature
    writeShort(0);          // number of this disk
    writeShort(0);          // central directory start disk
    writeShort(count);      // number of directory entries on disk
    writeShort(count);      // total number of directory entries
    writeInt(len);          // length of central directory
    writeInt(off);          // offset of central directory
    if (comment != null) {      // zip file comment
        byte[] b = getUTF8Bytes(comment);
        writeShort(b.length);
        writeBytes(b, 0, b.length);
    } else {
        writeShort(0);
    }
    }

    /*
     * Writes a 16-bit short to the output stream in little-endian byte order.
     */
    private void writeShort(int v) throws IOException {
    OutputStream out = this.out;
    out.write((v >>> 0) & 0xff);
    out.write((v >>> 8) & 0xff);
    written += 2;
    }

    /*
     * Writes a 32-bit int to the output stream in little-endian byte order.
     */
    private void writeInt(long v) throws IOException {
    OutputStream out = this.out;
    out.write((int)((v >>>  0) & 0xff));
    out.write((int)((v >>>  8) & 0xff));
    out.write((int)((v >>> 16) & 0xff));
    out.write((int)((v >>> 24) & 0xff));
    written += 4;
    }

    /*
     * Writes an array of bytes to the output stream.
     */
    private void writeBytes(byte[] b, int off, int len) throws IOException {
    super.out.write(b, off, len);
    written += len;
    }

    /*
     * Returns the length of String's UTF8 encoding.
     */
    static int getUTF8Length(String s) {
        int count = 0;
        for (int i = 0; i < s.length(); i++) {
            char ch = s.charAt(i);
            if (ch <= 0x7f) {
                count++;
            } else if (ch <= 0x7ff) {
                count += 2;
            } else {
                count += 3;
            }
        }
        return count;
    }

    /*
     * Returns an array of bytes representing the UTF8 encoding
     * of the specified String.
     */
    private static byte[] getUTF8Bytes(String s) {
    char[] c = s.toCharArray();
    int len = c.length;
    // Count the number of encoded bytes...
    int count = 0;
    for (int i = 0; i < len; i++) {
        int ch = c[i];
        if (ch <= 0x7f) {
        count++;
        } else if (ch <= 0x7ff) {
        count += 2;
        } else {
        count += 3;
        }
    }
    // Now return the encoded bytes...
    byte[] b = new byte[count];
    int off = 0;
    for (int i = 0; i < len; i++) {
        int ch = c[i];
        if (ch <= 0x7f) {
        b[off++] = (byte)ch;
        } else if (ch <= 0x7ff) {
        b[off++] = (byte)((ch >> 6) | 0xc0);
        b[off++] = (byte)((ch & 0x3f) | 0x80);
        } else {
        b[off++] = (byte)((ch >> 12) | 0xe0);
        b[off++] = (byte)(((ch >> 6) & 0x3f) | 0x80);
        b[off++] = (byte)((ch & 0x3f) | 0x80);
        }
    }
    return b;
    }
}
于 2011-04-24T04:08:57.967 回答
1

我相信目前的 API 无法做到这一点。
您可以将数据附加到任何文件,但这并不意味着您最终会得到正确的文件格式。文件.zip不像.tar文件,压缩要求对文件的处理(文件位置、EOF 等)施加了限制。如果您考虑文件格式的结构(取自此处的维基百科),您将理解为什么仅附加不起作用。

有一个名为TrueZip的库可以工作,虽然我不知道它是否支持 android。在另一个类似的问题中查看这个答案: Appending files to a zip file with Java

此外,作为一种解决方法,您可以创建单个.zip文件并将它们附加为 tarball(此处为文件格式)。压缩可能稍微差一点,但在时间效率方面会好得多。


根据评论更新(和可能的解决方案)

只要您仍在拍照,您就可以将添加的内容分开ZipEntry并让对象保持打开状态。ZipOutputStream不过,我可以看到这种方法的风险,因为在拍照时应用程序出现任何问题(强制关闭、电池耗尽等)都可能导致整个文件无法使用。您需要确保使用正确的 try/catch/finally 块来关闭文件并调用closeZip()诸如onClose()and之类的事件onDestroy(),但想法如下:

import java.io.*;
import java.util.zip.*;

public class Zip {
    static final int BUFFER = 2048;

    ZipOutputStream out;
    byte data[];

    public Zip(String name) {
        FileOutputStream dest = new FileOutputStream(name);
        out = new ZipOutputStream(new BufferedOutputStream(dest));
        data = new byte[BUFFER];
    }

    public void addFile (String name) {
        FileInputStream fi = new FileInputStream(name);
        BufferedInputStream origin = new BufferedInputStream(fi, BUFFER);
        ZipEntry entry = new ZipEntry(name);
        out.putNextEntry(entry);
        int count;
        while((count = origin.read(data, 0, BUFFER)) != -1) {
           out.write(data, 0, count);
        }
        origin.close();
     }

    public void closeZip () {
        out.close();
    }
}
于 2011-04-21T05:12:20.217 回答