hadoop API 写入HDFS简单注释

import java.io.BufferedInputStream;
import java.io.FileInputStream;
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;
import org.apache.hadoop.io.IOUtils;
import org.apache.hadoop.util.Progressable;
// vv FileCopyWithProgress
public class FileCopyWithProgress {
  public static void main(String[] args) throws Exception {
    String localSrc = args[0];
    String dst = args[1];
    
    InputStream in = new BufferedInputStream(new FileInputStream(localSrc));
    //建立一个本地的InputStream
    Configuration conf = new Configuration();//建立接口
    FileSystem fs = FileSystem.get(URI.create(dst), conf);//创建文件系统实例
    OutputStream out = fs.create(new Path(dst), new Progressable() {
      public void progress() {
        System.out.print(".");
      }//通过实例创建管道 create方法返回的是FSDataOutputStream对象
    });
    
    IOUtils.copyBytes(in, out, 4096, true);//通过管道进行写入
  }
}