package dao;

import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.fs.*;

import java.io.*;

public class HDFSApi {

    /**

     * 读取文件内容

     */

    public static void cat(Configuration conf, String remoteFilePath) throws IOException {

        FileSystem fs = FileSystem.get(conf);

        Path remotePath = new Path(remoteFilePath);

        FSDataInputStream in = fs.open(remotePath);

        BufferedReader d = new BufferedReader(new InputStreamReader(in));

        String line = null;

        while ((line = d.readLine()) != null) {

            String[] strarray = line.split(" ");

            for (int i = 0; i < strarray.length; i++) {

                System.out.print(strarray[i]);

                System.out.print(" ");

            }

            System.out.println(" ");

            // System.out.println(line);

            // System.out.print(strarray[0]);

        }

        d.close();

        in.close();

        fs.close();

    }

    /**

     * 主函数

     */

    public static void main(String[] args) {

        Configuration conf = new Configuration();

        conf.set("fs.default.name", "hdfs://yt:9000");

        String remoteFilePath = "/hadoop/hadoop1.txt"; // HDFS路径

        try {

            System.out.println("读取文件: " + remoteFilePath);

            HDFSApi.cat(conf, remoteFilePath);

            System.out.println("\n读取完成");

        } catch (Exception e) {

            e.printStackTrace();

        }

    }

}