hadoop使用

1.编写Java 代码

package edu.jmi.hdfsclient;

import java.io.IOException;

import java.net.socket;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path/* * Hello World! *

 */
public class AppTest 
{
    public static void main( String[] args ) throws Exception, IOException
    {
        upload();
    }
    public static void download() throws IOException {    
        Configuration conf = new Configuration();        
        conf.set("fs.defaultFS","hdfs://192.168.159.134:9000");        
        FileSystem fs = FileSystem.newInstance(conf);      
        fs.copyToLocalFile(new Path("/start-all.sh"),new Path("e://"));   
    }
    public static void upload() throws IOException {    
    Configuration conf = new Configuration();     
         conf.set("fs.defaultFS","hdfs://192.168.159.134:9000");     
         FileSystem fs = FileSystem.get(conf);
         Path src=new Path("d://my.txt");
         Path dest=new Path("/");
         fs.copyFromLocalFile(src,dest);
         FileStatus[] fileStatus  = fs.listStatus(dest);
         for(FileStatus file:fileStatus){
          System.out.println(file.getPath());
       }
         System.out.println("上传成功");
    }
    public static void test()throws Exception{
        Socket socket=new Socket("192.168.159.134",9000);
        System.out.println(socket);//查看网络是否相同，拒绝说明防火墙开了，外界无法访问到网络。关一下就好了
    }

}

 

 

 

 

 

 2.编写map与reduce函数