如果超过最大限制，则拆分文件阵列

Question

我想按大小拆分文件数组。我设置的最大大小是4MB。如果总大小<=最大大小，我添加到新的List。

这里我的方法：

public List<File> fileSplit(File [] files, long maxAttachmentSize) {
        int i = 0;
        long totalAttachmentSize = 0;
        List<File> list = new ArrayList<File>();
        for (int j = 0; j < files.length; j++) {
            File file = files[i];
            totalAttachmentSize += file.length();
            list.add(file);
            if (totalAttachmentSize > maxAttachmentSize) {
                //part += 1;
                break;
            }
        }
        return list;
}

这是我的数组：

String [] attachments = {
                "/Users/fanjavaid/Documents/data.json",
                "/Users/fanjavaid/Documents/master.psd",
                "/Users/fanjavaid/Pictures/ceria.jpg",
                "/Users/fanjavaid/Desktop/All Data LM.dsv",     
                "/Users/fanjavaid/Desktop/LM August 01 - Now.xlsx",
                "/Users/fanjavaid/Desktop/Email_GoGreen.png",
                "/Users/fanjavaid/Desktop/Archive.zip",
                "/Users/fanjavaid/Desktop/Email_Veri2144202172009.zip",
                "/Users/fanjavaid/Desktop/Screenshot Collection.zip",
                "/Users/fanjavaid/Desktop/logo-big.jpg",
                "/Users/fanjavaid/Desktop/Mbak Putri.psd"
        };
        File [] files = convertToFile(attachments);
        Arrays.sort(files, SizeFileComparator.SIZE_COMPARATOR);

……

我调用这样的方法：

long maxAttachmentSize = 4194304; // in bytes
List<File> resultSplit = fileSplit(files, maxAttachmentSize);

问题是它没有将List作为一部分返回。它只是返回所有列表。没有一部分一部分地分开。如何处理？

谢谢。

Answer 1

假设没有文件大于最大大小，则可以执行此

public List<List<File>> fileSplit(File [] files, long maxAttachmentSize) {
  long totalAttachmentSize = 0;
  List<List<File>> allLists = new ArrayList<>();
  List<File> currList = new ArrayList<File>();
  allLists.add(currList);
  for (File file : files) {
    long fileSize = file.length();
    if ((totalAttachmentSize + fileSize) <= maxAttachmentSize) {
      currList.add(file);
      totalAttachmentSize += fileSize;
    } else {
      totalAttachmentSize = fileSize;
      currList = new ArrayList<File>();
      allLists.add(currList);
      currList.add(file); // assuming no file is bigger than maxAttachmentSize
    }
  }
  return allLists;
}