将数据添加到zip文件头

Question

我正在尝试将数据添加到zip文件头字段。特别是使用java进入zip头中指定的额外字段。可能吗 ？

public class test {
public static void main(String[] args) {

    String path = "finalName.zip";
RandomAccessFile file = null;
try {
    file = new RandomAccessFile(path, "rw");

    byte[] buf = new byte[(int) file.length() / 1024];

    file.read(buf);

    byte[] newHeader =  "NEW DATA".getBytes();

    System.out.println("Original zip : "  + bytesToHex(buf));
    System.out.println("newHeader   : "  + bytesToHex(newHeader));

    int length = newHeader.length;
    buf[28] = (byte) length;

    byte[] firstPart = Arrays.copyOf(buf, 30);
    byte[] endPart = Arrays.copyOfRange(buf, 30, buf.length );

    System.out.println("firstPart zip original : "  + bytesToHex(firstPart));
    System.out.println("endPart zip original : "  + bytesToHex(endPart));

    byte[] firstPartAndHeader = new byte[30 + length];
    System.arraycopy(firstPart, 0, firstPartAndHeader, 0, firstPart.length);
    System.arraycopy(newHeader, 0, firstPartAndHeader, firstPart.length, newHeader.length);
    System.out.println("firstPartAndHeader zip original : "  + bytesToHex(firstPartAndHeader));

    byte[] combined = new byte[firstPartAndHeader.length + endPart.length];
    System.arraycopy(firstPartAndHeader, 0, combined, 0, firstPartAndHeader.length);
    System.arraycopy(endPart, 0, combined, firstPartAndHeader.length, endPart.length);

    System.out.println("combined zip original : "  + bytesToHex(combined));

    file.seek(0);
    file.write(combined);
    file.close();

} catch (IOException e) {
    e.printStackTrace();
}


}

private final static char[] hexArray = "0123456789ABCDEF".toCharArray();
public static String bytesToHex(byte[] bytes) {
    char[] hexChars = new char[bytes.length * 2];
    for ( int j = 0; j < bytes.length; j++ ) {
        int v = bytes[j] & 0xFF;
        hexChars[j * 2] = hexArray[v >>> 4];
        hexChars[j * 2 + 1] = hexArray[v & 0x0F];
    }
    return new String(hexChars);
}
}

我的方式是破坏文件。我在字节28中添加了额外标头的长度，在字节30中添加了额外的标头。还有什么需要做的吗？