基于hadoop网络云盘上传和下载的代码实现

这是一个基于Hadoop网络的云盘上传和下载的代码实现，主要用到了Hadoop的HDFS和MapReduce框架。

上传部分：

1. 首先，定义一个上传的Mapper类，继承自Hadoop的Mapper类，实现map函数。

public static class UploadMapper extends Mapper<LongWritable, Text, Text, BytesWritable> {
private Text filename = new Text();

public void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException {
String filepath = value.toString();
File file = new File(filepath);
filename.set(file.getName());

byte[] data = new byte[(int) file.length()];
FileInputStream fis = new FileInputStream(file);
fis.read(data);
fis.close();

context.write(filename, new BytesWritable(data));
}
}

2. 然后，定义一个上传的Reducer类，继承自Hadoop的Reducer类，实现reduce函数。

public static class UploadReducer extends Reducer<Text, BytesWritable, Text, Text> {
public void reduce(Text key, Iterable<BytesWritable> values, Context context) throws IOException, InterruptedException {
Configuration conf = context.getConfiguration();
String hdfsPath = conf.get("hdfsPath");
String filepath = hdfsPath + "/" + key.toString();

Path path = new Path(filepath);
FileSystem fs = path.getFileSystem(conf);
FSDataOutputStream out = fs.create(path);

for (BytesWritable value : values) {
out.write(value.getBytes(), 0, value.getLength());
}

out.close();

context.write(key, new Text("Upload completed!"));
}
}

3. 最后，定义上传的Driver类，继承自Hadoop的Configured类和Tool类，实现run函数。

public int run(String[] args) throws Exception {
Configuration conf = getConf();

Job job = Job.getInstance(conf, "UploadFile");
job.setJarByClass(UploadFile.class);

job.setMapperClass(UploadMapper.class);
job.setReducerClass(UploadReducer.class);

job.setOutputKeyClass(Text.class);
job.setOutputValueClass(BytesWritable.class);

job.setInputFormatClass(TextInputFormat.class);
job.setOutputFormatClass(TextOutputFormat.class);

FileInputFormat.addInputPath(job, new Path(args[0]));
FileOutputFormat.setOutputPath(job, new Path(args[1]));

return job.waitForCompletion(true) ? 0 : 1;
}

下载部分：

1. 首先，定义一个下载的Mapper类，继承自Hadoop的Mapper类，实现map函数。

public static class DownloadMapper extends Mapper<Text, BytesWritable, Text, Text> {
public void map(Text key, BytesWritable value, Context context) throws IOException, InterruptedException {
Configuration conf = context.getConfiguration();
String localPath = conf.get("localPath");
String filepath = localPath + "/" + key.toString();

FileOutputStream fos = new FileOutputStream(filepath);
fos.write(value.getBytes(), 0, value.getLength());
fos.close();

context.write(key, new Text("Download completed!"));
}
}

2. 然后，定义下载的Driver类，继承自Hadoop的Configured类和Tool类，实现run函数。

public int run(String[] args) throws Exception {
Configuration conf = getConf();

Job job = Job.getInstance(conf, "DownloadFile");
job.setJarByClass(DownloadFile.class);

job.setMapperClass(DownloadMapper.class);

job.setOutputKeyClass(Text.class);
job.setOutputValueClass(BytesWritable.class);

job.setInputFormatClass(KeyValueTextInputFormat.class);
job.setOutputFormatClass(TextOutputFormat.class);

FileInputFormat.addInputPath(job, new Path(args[0]));
FileOutputFormat.setOutputPath(job, new Path(args[1]));

return job.waitForCompletion(true) ? 0 : 1;
}

以上就是基于Hadoop网络的云盘上传和下载的代码实现。