【Hadoop】HA 场景下访问 HDFS JAVA API Client

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);
    }
}