當hadoop namenode是HA叢集時，客戶端遠端訪問hdfs有兩種實現方法：
方法1：將所有關於namenode的引數寫入Configuration物件中。
程式碼：

package com.lx;

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;

public class Demo {

    private static void uploadToHdfs() throws Exception {
        //本地檔案地址
        String localSrc = "d:/PowerDesigner15_Evaluation.rar";
        //存放在hdfs的目的地址
        String dest = "/user/PowerDesigner15_Evaluation.rar"
 
;
        InputStream in = new BufferedInputStream(new FileInputStream(localSrc));
        //得到配置物件
        Configuration conf = new Configuration();

        conf.set("fs.defaultFS", "hdfs://ns1");
        conf.set("dfs.nameservices", "ns1");
        conf.set("dfs.ha.namenodes.ns1", "nn1,nn2");
        conf.set
 
("dfs.namenode.rpc-address.ns1.nn1", "hadoop1:9000");
        conf.set("dfs.namenode.rpc-address.ns1.nn2", "hadoop2:9000");
        conf.set("dfs.client.failover.proxy.provider.ns1", "org.apache.hadoop.hdfs.server.namenode.ha.ConfiguredFailoverProxyProvider");



        //檔案系統
        FileSystem fs = FileSystem.get(new URI("hdfs://ns1"), conf, "hadoop");
        //輸出流
        OutputStream out = fs.create(new Path(dest));
        //連線兩個流，形成通道，使輸入流向輸出流傳輸資料
        IOUtils.copyBytes(in, out, 4096, true);
    }

    public static void main(String[] args) throws Exception{
        // TODO Auto-generated method stub
        uploadToHdfs();
    }

}

方法2：將hadoop叢集配置檔案core-site.xml和hdfs-site.xml檔案拷貝到專案的src目錄下。

程式碼：

package com.lx;

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;

public class Demo2 {

    public static void main(String[] args) throws Exception{
        // TODO Auto-generated method stub
        String src="d:/RoseHA.rar";
        String dst="/user/RoseHA.rar";

        InputStream in=new BufferedInputStream(new FileInputStream(src));

        Configuration conf=new Configuration();

        FileSystem fs=FileSystem.get(new URI("hdfs://ns1"), conf, "hadoop");

        OutputStream out=fs.create(new Path(dst));

        IOUtils.copyBytes(in, out, 4096, true);
    }

}