java - 使用 ZipOutputStream 压缩时 zip 无效

Question

在写入以下代码时，我得到无效的 zip:

public static byte[] zip(final Map<String, byte[]> mapReports) {

  try (ByteArrayOutputStream baos = new ByteArrayOutputStream();
      ZipOutputStream zos = new ZipOutputStream(baos)) {
    for (Map.Entry<String, byte[]> report : mapReports.entrySet()) {
      ZipEntry entry = new ZipEntry(report.getKey());
      zos.putNextEntry(entry);
      zos.write(report.getValue());
      zos.closeEntry();
    }
    return baos.toByteArray();
  } catch (Exception e) {
    throw new RuntimeException("Exception zipping files", e);
  }
}

我将其写入文件的方式是:

    byte[] zip = zip(mapReports);
    File file = new File("demo.zip");

    try {
        OutputStream os = new FileOutputStream(file);
        os.write(zip);
        os.close();
    } catch (Exception e) {
        e.printStackTrace();
    }

我做错了什么？

Answer 1

在调用 baos 之前，您需要close() 或 finish() ZipOutputStream 流 .toByteArray().

由于 ByteArrayOutputStream 不需要关闭，和/或即使在关闭后您也可以调用 toByteArray()，所以我建议您将其移到 try block 之外:

public static byte[] zip(final Map<String, byte[]> mapReports) {
  ByteArrayOutputStream baos = new ByteArrayOutputStream();
  try (ZipOutputStream zos = new ZipOutputStream(baos)) {
    for (Map.Entry<String, byte[]> report : mapReports.entrySet()) {
      zos.putNextEntry(new ZipEntry(report.getKey()));
      zos.write(report.getValue());
    }
  } catch (Exception e) {
    throw new RuntimeException("Exception zipping files", e);
  }
  return baos.toByteArray();
}