File block merger

1. File Block

File block process is as follows:

1. Getting the source length
2. The size of the file block number of blocks calculated set
3. Read data is sequentially written to each data block of the file from the source file.

//测试文件分块方法
    @Test
    public void testChunk() throws IOException {
        File sourceFile = new File("D:/test/ffmpeg/test.mp4");
        String chunkPath = "D:/test/ffmpeg/file/";
        File chunkFolder = new File(chunkPath);
        if (!chunkFolder.exists()) {
            chunkFolder.mkdirs();
        }
        //分块大小
        long chunkSize = 1024 * 1024 * 1;
        //分块数量
        long chunkNum = (long) Math.ceil(sourceFile.length() * 1.0 / chunkSize);
        if (chunkNum <= 0) {
            chunkNum = 1;
        }
        //缓冲区大小
        byte[] b = new byte[1024];
        //使用RandomAccessFile访问文件
        RandomAccessFile raf_read = new RandomAccessFile(sourceFile, "r");
        //分块
        for (int i = 0; i < chunkNum; i++) {
            //创建分块文件
            File file = new File(chunkPath + i);
            boolean newFile = file.createNewFile();
            if (newFile) {
                //向分块文件中写数据
                RandomAccessFile raf_write = new RandomAccessFile(file, "rw");
                int len = -1;
                while ((len = raf_read.read(b)) != -1) {
                    raf_write.write(b, 0, len);
                    if (file.length() > chunkSize) {
                        break;
                    }
                }
                raf_write.close();
            }
        }
        raf_read.close();
    }

2. File Merge

File merge process:

1. Find the file you want to merge files and press have to sort of merge.
2. Create a merge document
3. The combined data are sequentially read from the file writes to the combined file

//测试文件合并方法
    @Test
    public void testMerge() throws IOException {
        //块文件目录
        File chunkFolder = new File("D:/test/ffmpeg/file/");
        //合并文件
        File mergeFile = new File("D:/test/ffmpeg/test1.mp4");
        if (mergeFile.exists()) {
            mergeFile.delete();
        }
        //创建新的合并文件
        mergeFile.createNewFile();
        //用于写文件
        RandomAccessFile raf_write = new RandomAccessFile(mergeFile, "rw");
        //指针指向文件顶端
        raf_write.seek(0);
        //缓冲区
        byte[] b = new byte[1024];
        //分块列表
        File[] fileArray = chunkFolder.listFiles();
        //  转成集合，便于排序
        List<File> fileList = new ArrayList<File>(Arrays.asList(fileArray));
        //  从小到大排序
        Collections.sort(fileList, new Comparator<File>() {
            @Override
            public int compare(File o1, File o2) {
                if (Integer.parseInt(o1.getName()) < Integer.parseInt(o2.getName())) {
                    return -1;
                }
                return 1;
            }
        });
        //合并文件
        for (File chunkFile : fileList) {
            RandomAccessFile raf_read = new RandomAccessFile(chunkFile, "rw");
            int len = -1;
            while ((len = raf_read.read(b)) != -1) {
                raf_write.write(b, 0, len);
            }
            raf_read.close();
        }
        raf_write.close();
    }