Hadoop RPC API

一. 简述

本文使用Hadoop的RPC框架简略模拟了HDFS客户端向NameNode查询元数据的过程
项目结构如下

二. 代码实现

通信协议

public interface ClientNamenodeProtocol {
  // 定义协议版本号
  public static final long versionID = 1L;
  // 定义通信接口
  public String getMetaData(String path);
}

服务器端实现业务功能

public class MyNameNode implements ClientNamenodeProtocol {
// 模拟查询元数据
  @Override
  public String getMetaData(String path) {
      return "This is  meta data from " + path +
          " : replication - x, block locations - xxx";
  }
}

发布服务器

public class PublishServiceUtil {
    
  public static void main(String[] args) throws IOException {
      RPC.Builder builder = new RPC.Builder(new Configuration());
      builder.setBindAddress("localhost")
              .setPort(8888)
              .setProtocol(ClientNamenodeProtocol.class)
              .setInstance(new MyNameNode());

      RPC.Server server = builder.build();
      server.start();
  }
}

客户端

public class MyHDFSClient {

  public static void main(String[] args) throws IOException {
      InetSocketAddress inetSocketAddress = new InetSocketAddress("localhost", 8888);
      ClientNamenodeProtocol nameNode = RPC.getProxy(ClientNamenodeProtocol.class, 1L, inetSocketAddress, new Configuration());

      String metaData = nameNode.getMetaData("/users/root/hello.txt");
      System.out.println(metaData);
  }
}

Basic Use of RPC API

一. 简述

二. 代码实现

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