无法从Android上创建的ZIP存档中提取文件(特定于设备/操作系统)

时间:2012-06-14 18:22:09

标签: android zip 7zip

我正在使用以下代码在Android上创建存档:

    OutputStream os = new FileOutputStream(zipFile);
    ZipOutputStream zos = new ZipOutputStream(new BufferedOutputStream(os));
    try 
    {
        zos.setLevel(8);
        byte[] buffer = new byte[32768];
        for (VFile src : toPack)            
        {
            ZipEntry entry = new ZipEntry(src.name);
            zos.putNextEntry(entry);
            src.pushToStream(zos, buffer);
            src.close();
            zos.closeEntry();
        }
    }
    finally 
    {
        zos.close();
    }       

我发现只有一种可用的压缩方法 - DEFLATED(只有STORED替代可用)。这意味着归档始终使用一种方法进行压缩。

如果我在Android 2.3.4上运行此代码 - 我可以使用7Zip在Windows中解压缩文件;如果我在Android 3上运行它(或三星Galaxy Tab;不确定谁错了) - 7Zip显示存档列表,但无法解压缩文件说不支持的压缩方法。同时7Zip将 Deflate 显示为文件上的压缩方法,这意味着它可以正确处理它。

有人有这个问题吗?

感谢。

UDP:找到了另一个topic with similar issue(虽然可能不一样)。

2 个答案:

答案 0 :(得分:3)

@ user1269737的回答是正确的;几乎。但它仅适用于单文件存档。 下面是一个解析整个存档的代码。

/**
* Replace wrong local file header byte
* http://sourceforge.net/tracker/?func=detail&aid=3477810&group_id=14481&atid=114481
* Applies to Android API 9-13
* @param zip file
* @throws IOException
*/
private static void fixInvalidZipFile(File zip) throws IOException 
{
    RandomAccessFile r = new RandomAccessFile(zip, "rw");
    try
    {
        long eocd_offset = findEOCDRecord(r);

        if (eocd_offset > 0)
        {
            r.seek(eocd_offset + 16);  // offset of first CDE in EOCD               
            long cde_offset = readInt(r);  // read offset of first Central Directory Entry
            long lfh_offset = 0;
            long fskip, dskip;

            while (true)
            {
                r.seek(cde_offset);
                if (readInt(r) != CDE_SIGNATURE)  // got off sync!
                    return;

                r.seek(cde_offset + 20);  // compressed file size offset                
                fskip = readInt(r);

                // fix the header
                //
                r.seek(lfh_offset + 7);
                short localFlagsHi = r.readByte();  // hi-order byte of local header flags (general purpose)
                r.seek(cde_offset + 9);
                short realFlagsHi = r.readByte();  // hi-order byte of central directory flags (general purpose)
                if (localFlagsHi != realFlagsHi)
                { // in latest versions this bug is fixed, so we're checking is bug exists.
                    r.seek(lfh_offset + 7);
                    r.write(realFlagsHi);
                }

                //  calculate offset of next Central Directory Entry
                //
                r.seek(cde_offset + 28);  // offset of variable CDE parts length in CDE
                dskip = 46;  // length of fixed CDE part
                dskip += readShort(r);  // file name
                dskip += readShort(r);  // extra field
                dskip += readShort(r);  // file comment

                cde_offset += dskip;
                if (cde_offset >= eocd_offset)  // finished!
                    break;              

                // calculate offset of next Local File Header
                //
                r.seek(lfh_offset + 26);  // offset of variable LFH parts length in LFH
                fskip += readShort(r);  // file name
                fskip += readShort(r);  // extra field
                fskip += 30;  // length of fixed LFH part
                fskip += 16;  // length of Data Descriptor (written after file data)

                lfh_offset += fskip;
            }
        }
    }
    finally
    {
        r.close();
    }
}

//http://www.pkware.com/documents/casestudies/APPNOTE.TXT
private static final int LFH_SIGNATURE = 0x04034b50;
private static final int DD_SIGNATURE = 0x08074b50;
private static final int CDE_SIGNATURE = 0x02014b50;
private static final int EOCD_SIGNATURE = 0x06054b50;

/** Find an offset of End Of Central Directory record in file */
private static long findEOCDRecord(RandomAccessFile f) throws IOException
{
    long result = f.length() - 22; // 22 is minimal EOCD record length
    while (result > 0)
    {
        f.seek(result);

        if (readInt(f) == EOCD_SIGNATURE) return result;

        result--;
    }
    return -1;
}

/** Read a 4-byte integer from file converting endianness. */
private static int readInt(RandomAccessFile f) throws IOException
{
    int result = 0;
    result |= f.read();
    result |= (f.read() << 8);
    result |= (f.read() << 16);
    result |= (f.read() << 24);
    return result;
}

/** Read a 2-byte integer from file converting endianness. */
private static short readShort(RandomAccessFile f) throws IOException
{
    short result = 0;
    result |= f.read();
    result |= (f.read() << 8);
    return result;
}

答案 1 :(得分:1)

需要更新。它修复了单文件zip。您必须在zip文件{0,0x08,0x08,0x08,0}中查看以下序列并将其替换为{0,0x08,0x00,0x08,0}

/**
* Replace wrong byte http://sourceforge.net/tracker/?func=detail&aid=3477810&group_id=14481&atid=114481
* @param zip file
* @throws IOException
*/

private static void replaceWrongZipByte(File zip) throws IOException {
    RandomAccessFile  r = new RandomAccessFile(zip, "rw");
    int flag = Integer.parseInt("00001000", 2); //wrong byte
    r.seek(7);
    int realFlags = r.read();
    if( (realFlags & flag) > 0) { // in latest versions this bug is fixed, so we're checking is bug exists.
        r.seek(7);
        flag = (~flag & 0xff);
        // removing only wrong bit, other bits remains the same.
        r.write(realFlags & flag);
    }
    r.close();
}

更新版本:

以下代码删除ZIP中的所有错误字节。 在Google中很容易找到KMPMatch.java

public static void replaceWrongBytesInZip(File zip) throws IOException {
    byte find[] = new byte[] { 0, 0x08, 0x08, 0x08, 0 };
    int index;
    while( (index = indexOfBytesInFile(zip,find)) != -1) {
        replaceWrongZipByte(zip, index + 2);
    }
}

private static int indexOfBytesInFile(File file,byte find[]) throws IOException {
    byte fileContent[] = new byte[(int) file.length()];
    FileInputStream fin = new FileInputStream(file);
    fin.read(fileContent);
    fin.close();
    return KMPMatch.indexOf(fileContent, find);
}

/**
 * Replace wrong byte http://sourceforge.net/tracker/?func=detail&aid=3477810&group_id=14481&atid=114481
 * @param zip file
 * @throws IOException
 */
private static void replaceWrongZipByte(File zip, int wrongByteIndex) throws IOException {
    RandomAccessFile  r = new RandomAccessFile(zip, "rw");
    int flag = Integer.parseInt("00001000", 2);
    r.seek(wrongByteIndex);
    int realFlags = r.read();
    if( (realFlags & flag) > 0) { // in latest versions this bug is fixed, so we're checking is bug exists.
        r.seek(wrongByteIndex);
        flag = (~flag & 0xff);
        // removing only wrong bit, other bits remains the same.
        r.write(realFlags & flag);
    }
    r.close();
}