客户端需要指定ns名称，节点配置，ConfiguredFailoverProxyProvider等信息。
代码示例：
package cn.itacst.hadoop.hdfs;
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 HDFS_HA {
public static void main(String[] args) throws Exception {
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", "itcast01:9000");
conf.set("dfs.namenode.rpc-address.ns1.nn2", "itcast02:9000");
//conf.setBoolean(name, value);
conf.set("dfs.client.failover.proxy.provider.ns1", "org.apache.hadoop.hdfs.server.namenode.ha.ConfiguredFailoverProxyProvider");
FileSystem fs = FileSystem.get(new URI("hdfs://ns1"), conf, "hadoop");
InputStream in =new FileInputStream("c://eclipse.rar");
OutputStream out = fs.create(new Path("/eclipse"));
IOUtils.copyBytes(in, out, 4096, true);
}
}