由於mapreduce實驗總要檢視output/part-r-00000

所以寫個程式

package Utils;


import java.net.URI;


import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.log4j.Logger;


/**
 * 讀取hdfs上指定檔案中的內容
 * @company 源辰資訊
 * 
 
@author navy
 */
public class FindHDFSText {
    private static Logger log = Logger.getLogger(FindHDFSText.class);// 建立日誌記錄器


    public static void main(String[] args) {
        FileSystem fs = null;
        try {
            Configuration conf = new Configuration();// 載入配置檔案
            conf.set("dfs.client.use.datanode.hostname", "true");
            URI uri 
 
= new URI("hdfs://**:9000/"); // 連線資源位置

            fs = FileSystem.get(uri,conf,"hadoop"); // 建立檔案系統例項物件
            
            Path p= new Path("output/part-r-00000"); // 預設是讀取/user/navy/下的指定檔案


            System.out.println("要檢視的檔案路徑為："+fs.getFileStatus(p).getPath());

            FSDataInputStream fsin 
 
= fs.open(fs.getFileStatus(p).getPath());
            byte[] bs = new byte[1024 * 1024];
            int len = 0;
            while((len = fsin.read(bs)) != -1){
                System.out.print(new String(bs, 0, len));
            }

            System.out.println();
            fsin.close();
        } catch (Exception e) {
            log.error("hdfs操作失敗!!!", e);
        }
    }
}