HDFS实战之打开文件

  1. 源码如下
package shen.liu.hdfs.practice;

import java.io.IOException;
import java.io.InputStream;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.zookeeper.common.IOUtils;

public class HDFSFileCat {
    public static void main(String args[]) throws IOException {
        if(args.length!=1) {
            System.out.println("args.length = "+args.length);
            System.out.println("parameter error");
        }else {
            Configuration conf = new Configuration();//新建一个配置
            FileSystem hdfs = FileSystem.get(conf);//

            Path path = new Path(args[0]);
            InputStream in = null;
            try {
                in = hdfs.open(path);
                IOUtils.copyBytes(in,System.out,4096,false);
            }finally {
                IOUtils.closeStream(in);
                //不管是否抛出异常，本语句都会执行
            }
        }
    }
}