Android 将文件附加到 zip 文件而无需重新编写整个 zip 文件? [英] Android append files to a zip file without having to re-write the entire zip file?
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问题描述
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，它运行良好.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，如果你拍了足够多的照片，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.在拍摄照片时，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.:-)
How can I append files to an existing zip file? I already have the code that can create a zip file and it works great except for one big problem. The way it works now, the user takes a bunch of pictures, and at the end, all the pictures get added to a zip file, which can take quite a while if you take enough pictures. :-( So I'm thinking, I have a very good and efficient solution. As the pictures are taken, I will simply add the each new picture to the zip file right after it's taken. Then when they're done taking pictures, finish up the zip file so it's usable and export it. :-)
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，我确实理解为 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，这很可能会在很长时间之后，甚至可能是一个小时之后，这就是为什么我每次迭代都重置所有内容，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，然后我实际上将放弃 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.:-)
The problem is, I can not get it to add files to an existing zip file. :-( Here's what I have so far. Also, please keep in mind, this is just a proof of concept, I do understand that re-initializing everything for every iteration of the for loop is very dumb. Each iteration of the loop is supposed to represent another file being added which will most likely be a long time later, maybe even an hour later, which is why I have everything resetting each iteration, because the app will be shut down between adding files. If I can get this working, then I will actually ditch the for loop and put this code into a function that gets called every time a picture gets taken. :-)
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提取的所有文件，这很糟糕.:-( 那么有没有办法开始编写一个 zip 文件，然后再添加到它，并完成 zip 文件?我什至想过可能采用 ZipOutputStream 并修改它以适应我需要的这个模型.它应该在逻辑上以某种方式可能吗?:-)
If you notice, I set append to true, which will actually append the data to an existing file. And what's interesting is, it actually does append the data to the original file, however, after the file gets extracted on my computer, the last file written is all that gets extracted, which is bad. :-( So is there some way to start writing a zip file, and then later, add on to it, and finish up the zip file? I've even thought about possibly taking ZipOutputStream and modifying it to fit this model that I need. It should logically be possible somehow? :-)
在此先感谢您的帮助！:-D
Thanks in advance for the help! :-D
-贾里德
推荐答案
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，你可以在之后添加文件关闭文件，只要你保存你的位置！！！:-D
Ok, thanks for all your suggestions, but I was able to get it working like I wanted.... it CAN be done, you CAN add files after closing the file, as long as you save your place!!! :-D
这是我如何让它开始工作:
Here's how I was able to get it going working:
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，以便可以公开我在 ZipOutputStreamNew 类中创建的以下函数......
Also, keep in mind, this is not the only code I had to do. I also had to make my own copy of ZipOutputStream so that I could expose the following functions that I created within my ZipOutputStreamNew class....
getWritten()
getXentries()
以及
setWritten(long mWritten)
setXentries(Vector<XEntry> mXEntries)
在大多数情况下，这一切都是像正常一样开始写入，然后，不是像正常一样关闭，而是备份这两个变量，然后在下一次迭代中，它只恢复那些变量.
For the most part, all this does, is it starts writing like normal, then, instead of closing like normal, it backs up those two variables, and then for the next iteration, it restores just those variables.
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的位置.:-D
Let me know if you have any questions about all this, but I knew it would work, all it has to do is save where it was. :-D
再次感谢大家的帮助！:-)
Thanks again for all the help everybody! :-)
应 Raj 的要求，这里是 ZipOutputStreamNew 的源代码:
At Raj's request, here is the source code for ZipOutputStreamNew:
/**
* 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;
}
}
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