如何从Java中读取Winzip自解压缩（exe）zip文件？ [英] How can I read from a Winzip self-extracting (exe) zip file in Java?

问题描述

是否有现有方法或者我需要在将数据传递给ZipInputStream之前手动解析并跳过exe块？

Is there an existing method or will I need to manually parse and skip the exe block before passing the data to ZipInputStream?

推荐答案

审核了 EXE文件格式和 ZIP文件格式并测试它出现的各种选项最简单的解决方案是忽略第一个zip本地文件头的任何前导码。

After reviewing the EXE file format and the ZIP file format and testing various options it appears the easiest solution is to just ignore any preamble up to the first zip local file header.

我编写了一个输入流过滤器以绕过前导码并且它完美运行：

I wrote an input stream filter to bypass the preamble and it works perfectly:

ZipInputStream zis = new ZipInputStream(
    new WinZipInputStream(
    new FileInputStream("test.exe")));
while ((ze = zis.getNextEntry()) != null) {
    . . .
    zis.closeEntry();
}
zis.close();

---

WinZipInputStream.java

import java.io.FilterInputStream;
import java.io.InputStream;
import java.io.IOException;

public class WinZipInputStream extends FilterInputStream {
    public static final byte[] ZIP_LOCAL = { 0x50, 0x4b, 0x03, 0x04 };
    protected int ip;
    protected int op;

    public WinZipInputStream(InputStream is) {
        super(is);
    }

    public int read() throws IOException {
        while(ip < ZIP_LOCAL.length) {
            int c = super.read();
            if (c == ZIP_LOCAL[ip]) {
                ip++;
            }
            else ip = 0;
        }

        if (op < ZIP_LOCAL.length)
            return ZIP_LOCAL[op++];
        else
            return super.read();
    }

    public int read(byte[] b, int off, int len) throws IOException {
        if (op == ZIP_LOCAL.length) return super.read(b, off, len);
        int l = 0;
        while (l < Math.min(len, ZIP_LOCAL.length)) {
            b[l++] = (byte)read();
        }
        return l;
    }
}

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