Hadoop_12_Hadoop 中的RPC框架演示

package cn.bigdata.hdfs.hadoopRpc.protocol;

//定义业务接口方法
public interface ClientNamenodeProtocol {
    // 协议版本号
    public static final long versionID = 1L;
    public String getMetaData(String path);
}

package cn.bigdata.hdfs.hadoopRpc.service;

import cn.bigdata.hdfs.hadoopRpc.protocol.ClientNamenodeProtocol;

public class MyNameNode implements ClientNamenodeProtocol{

    @Override
    public String getMetaData(String path) {
        // 模拟NameNode的业务方法，获取元数据
        return path+": 3 - {BLK_1,BLK_2} ...";
    }
}

package cn.bigdata.hdfs.hadoopRpc.service;

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.ipc.RPC;
import org.apache.hadoop.ipc.RPC.Builder;
import org.apache.hadoop.ipc.RPC.Server;

import cn.bigdata.hdfs.hadoopRpc.protocol.ClientNamenodeProtocol;

//使用下面的代码可以把业务类发布为一个服务
public class PublishServiceUtil {
    public static void main(String[] args) throws IOException {
        Builder builder = new RPC.Builder(new Configuration());
        builder.setBindAddress("localhost")
        .setPort(8888)
        .setProtocol(ClientNamenodeProtocol.class)
        .setInstance(new MyNameNode());
        
        Server build = builder.build();
        build.start();
    }
}

package cn.bigdata.hdfs.hadoopRpc.client;
import java.net.InetSocketAddress;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.ipc.RPC;

import cn.bigdata.hdfs.hadoopRpc.protocol.ClientNamenodeProtocol;

public class MyHdfsClient {
    public static void main(String[] args) throws Exception {
        //获取代理对象
        ClientNamenodeProtocol nameNode = RPC.getProxy(ClientNamenodeProtocol.class, 
                1L, // 这里指定的协议版本号要跟接口中的versionID的值保持一致
                new InetSocketAddress("localhost",8888), 
                new Configuration());
        
        String metaData = nameNode.getMetaData("/angelababy");
        System.out.println(metaData);
    }
}