ZipInputStream转换

Question

我有一个java服务，它接受一个字节数组，以便将其转换为一个或多个pdf文件或jpg文件。我知道这项服务是有效的，因为它是从另一个正确发送文件而没有问题的java系统调用的。现在我需要从一个角度js系统调用这个服务，字节数组一旦到达java应用程序，它首先转换为ByteArrayInputStream而没有问题，然后ByteArrayInputStream转换为ZipInputStream但失败了。我怀疑问题是数组的编码类型。

这是我的代码：

public static Hashtable<String, ByteArrayOutputStream> unzipFile(InputStream inputStream){
    logger.info("Unzip del File");
    Hashtable<String, ByteArrayOutputStream> fileOutputTable = new Hashtable<String, ByteArrayOutputStream>();
    try{
        byte[] buf = new byte[1024];
        ZipEntry zipentry;
        ByteArrayInputStream bis = (ByteArrayInputStream)inputStream;
        ZipInputStream zipinputstream = new ZipInputStream(bis); // here conversion fail
        while((zipentry = zipinputstream.getNextEntry()) != null){
            String entryName = zipentry.getName();
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            int n = 0;
            while((n = zipinputstream.read(buf, 0, 1024)) > -1)
                baos.write(buf, 0, n);
            baos.close();
            fileOutputTable.put(entryName, baos);
            zipinputstream.closeEntry();
        }
        zipinputstream.close();
    }catch(Exception e){
        logger.error("Errore nel tentativo di unzip del file");
        e.printStackTrace();
    }
    logger.info("RETURN: " + fileOutputTable.toString());
    return fileOutputTable;
}

public static Hashtable<String, ByteArrayOutputStream> unzipFile(InputStream inputStream){
    logger.info("Unzip del File");
    Hashtable<String, ByteArrayOutputStream> fileOutputTable = new Hashtable<String, ByteArrayOutputStream>();
    try{
        byte[] buf = new byte[1024];
        ZipEntry zipentry;
        ByteArrayInputStream bis = (ByteArrayInputStream)inputStream;
        ZipInputStream zipinputstream = new ZipInputStream(bis); // here conversion fail
        while((zipentry = zipinputstream.getNextEntry()) != null){
            String entryName = zipentry.getName();
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            int n = 0;
            while((n = zipinputstream.read(buf, 0, 1024)) > -1)
                baos.write(buf, 0, n);
            baos.close();
            fileOutputTable.put(entryName, baos);
            zipinputstream.closeEntry();
        }
        zipinputstream.close();
    }catch(Exception e){
        logger.error("Errore nel tentativo di unzip del file");
        e.printStackTrace();
    }
    logger.info("RETURN: " + fileOutputTable.toString());
    return fileOutputTable;
}