将图像/视频存储到 Hadoop HDFS [英] Store images/videos into Hadoop HDFS

问题描述

我想将一些视频/图像存储到 Hadoop HDFS，但我听说HDFS 只接受像文本这样的文件.

I would like to store some videos/images into Hadoop HDFS, but I heard that HDFS accepts only files like as a text.

可以肯定的是，我们可以将视频/图像存储到 HDFS 中吗?如果是，那么这样做的方法或步骤是什么?

To be sure, can we store videos/images into HDFS? If yes, what's the way or the steps to follow to do that?

推荐答案

完全可以不做任何额外的事情.Hadoop 为我们提供了读/写二进制文件的工具.因此，几乎任何可以转换为字节的东西都可以存储到 HDFS(图像、视频等)中.为此，Hadoop 提供了称为SequenceFiles 的内容.SequenceFile 是一个由二进制键/值对组成的平面文件.SequenceFile 提供了 Writer、Reader 和 Sorter 类，分别用于写入、读取和排序.因此，您可以将图像/视频文件转换为 SeuenceFile 并将其存储到 HDFS 中.这是一小段代码，它将获取图像文件并将其转换为 SequenceFile，其中文件名是键，图像内容是值:

It is absolutely possible without doing anything extra. Hadoop provides us the facility to read/write binary files. So, practically anything which can be converted into bytes can be stored into HDFS(images, videos etc). To do that Hadoop provides something called as SequenceFiles. SequenceFile is a flat file consisting of binary key/value pairs. The SequenceFile provides a Writer, Reader and Sorter classes for writing, reading and sorting respectively. So, you could convert your image/video file into a SeuenceFile and store it into the HDFS. Here is small piece of code that will take an image file and convert it into a SequenceFile, where name of the file is the key and image content is the value :

public class ImageToSeq {
    public static void main(String args[]) throws Exception {

        Configuration confHadoop = new Configuration();     
        confHadoop.addResource(new Path("/hadoop/projects/hadoop-1.0.4/conf/core-site.xml"));
        confHadoop.addResource(new Path("/hadoop/projects/hadoop-1.0.4/conf/hdfs-site.xml"));   
        FileSystem fs = FileSystem.get(confHadoop);
        Path inPath = new Path("/mapin/1.png");
        Path outPath = new Path("/mapin/11.png");
        FSDataInputStream in = null;
        Text key = new Text();
        BytesWritable value = new BytesWritable();
        SequenceFile.Writer writer = null;
        try{
            in = fs.open(inPath);
            byte buffer[] = new byte[in.available()];
            in.read(buffer);
            writer = SequenceFile.createWriter(fs, confHadoop, outPath, key.getClass(),value.getClass());
            writer.append(new Text(inPath.getName()), new BytesWritable(buffer));
        }catch (Exception e) {
            System.out.println("Exception MESSAGES = "+e.getMessage());
        }
        finally {
            IOUtils.closeStream(writer);
            System.out.println("last line of the code....!!!!!!!!!!");
        }
    }
}

如果您的目的只是按原样转储文件，您可以简单地这样做:

And if your intention is to just dump the files as it is, you could simply do this :

bin/hadoop fs -put /src_image_file /dst_image_file

如果您的目的不仅仅是存储文件，您可能会发现 HIPI 很有用.HIPI 是 Hadoop 的 MapReduce 框架的库，它提供了一个 API，用于在分布式计算环境中执行图像处理任务.

And if your intent is more than just storing the files, you might find HIPI useful. HIPI is a library for Hadoop's MapReduce framework that provides an API for performing image processing tasks in a distributed computing environment.

HTH

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