将存储在本地的大量分散的小文件，合并并保存在hdfs文件系统中

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URI;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;

public class PutMerge {

    private InputStream in = null;
    private OutputStream out = null;
    private String localPath;
    private String hdfsPath;

    public PutMerge(String localPath, String hdfsPath) {
        this.localPath = localPath;
        this.hdfsPath = hdfsPath;
    }

    public void start() throws Exception {
        File file = new File(localPath);
        Configuration conf = new Configuration();

        FileSystem fs = FileSystem.get(URI.create(hdfsPath), conf);
        out = fs.create(new Path(hdfsPath));

        work(file);

        close();
    }

    /*
     * 1.根据用户定义的参数设置本地目录和HDFS的目标文件
     *
     * 2.创建一个输出流写入到HDFS文件
     *
     * 3.遍历本地目录中的每个文件，打开文件，并读取文件内容，将文件的内容写到HDFS文件中。
     */
    private void work(File file) throws Exception {
        if (file.isFile()) {
            int byteRead = 0;
            byte[] buffer = new byte[256];
            while ((byteRead = in.read(buffer)) > 0) {
                out.write(buffer, 0, byteRead);
            }
        } else if (file.isDirectory()) {
            File[] files = file.listFiles();
            for (int i = 0; i < files.length; i++) {
                if (files[i].isFile()) {
                    in = new BufferedInputStream(new FileInputStream(files[i]));
                    int byteRead = 0;
                    byte[] buffer = new byte[256];
                    while ((byteRead = in.read(buffer)) > 0) {
                        out.write(buffer, 0, byteRead);
                    }
                } else {
                    work(files[i]);
                }
            }
        }
    }

    private void close() throws IOException {
        if (in != null) {
            in.close();
        }

        if (out != null) {
            out.close();
        }
    }

    /**
     * @param args
     * @throws IOException
     */
    public static void main(String[] args) throws Exception {
        if (args.length < 2) {
            System.out.println("Usage:\n\t " + PutMerge.class.getName()
                    + " [LocalPath] [HDFSPath]");
            System.exit(1);
        }
        new PutMerge(args[0], args[1]).start();
    }
}