1、安装环境
客户端idea，服务端c++，服务端需要linux环境，可以使用远程服务器获取虚拟机都可以
2、服务端准备
需要安装protobuf环境

1. 安装需要的依赖包：

yum -y install autoconf automake libtool curl make g++ unzip
unzip protobuf-master.zip
cd protobuf-master
./autogen.sh 
./configure
make
make check
make install

最后查看版本

protoc --version

2、创建用来交换数据格式
infor.proto文件

syntax = "proto2";
message my_message{
    required string startedTime =1;
    required string version=2;
    required double configuredCapacity=3;
    required double dfsUsed =4;
    required int32 fileNum=5;
    required int32 replicatedFilesNum =6;
    required int32 blockNum =7;
    required int32 livedNodeNum =8;
    required int32 decommissioningNodeNum=9;
 }

编译生成.h和cpp文件

protoc --proto_path=./ --cpp_out=./ ./infor.proto

会生成两个文件

3、服务端的主代码

#include <netinet/in.h> // for sockaddr_in
#include <sys/types.h>  // for socket
#include <sys/socket.h> // for socket
#include <unistd.h>
#include <stdio.h>  // for printf
#include <stdlib.h> // for exit
#include <string.h> // for bzero
#include <string>
#include <google/protobuf/message_lite.h>
#include <google/protobuf/io/coded_stream.h>
#include <google/protobuf/io/zero_copy_stream_impl_lite.h>
#include "infor.pb.h"

#define HELLO_WORLD_SERVER_PORT 8888
#define LENGTH_OF_LISTEN_QUEUE 20

int main()
{
    std::string time = "2015-06-25";
    std::string version = "0.0.1";
    double config = 2.0;
    double dfs = 3.0;
    int file = 1000;
    int rep = 1000;
    int block = 1000;
    int live = 1000;
    int de = 1000;

    struct sockaddr_in server_addr;
    bzero(&server_addr, sizeof(server_addr));
    server_addr.sin_family = AF_INET;
    server_addr.sin_addr.s_addr = htons(INADDR_ANY);
    server_addr.sin_port = htons(HELLO_WORLD_SERVER_PORT);

    int server_socket = socket(PF_INET, SOCK_STREAM, 0);
    if (server_socket < 0)
    {
        printf("Create Socket Failed!");
        exit(1);
    }
    {
        int opt = 1;
        setsockopt(server_socket, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
    }

    if (bind(server_socket, (struct sockaddr *)&server_addr, sizeof(server_addr)))
    {
        printf("Server Bind Port : %d Failed!", HELLO_WORLD_SERVER_PORT);
        exit(1);
    }

    if (listen(server_socket, LENGTH_OF_LISTEN_QUEUE))
    {
        printf("Server Listen Failed!");
        exit(1);
    }
    while (true)
    {
        struct sockaddr_in client_addr;
        socklen_t length = sizeof(client_addr);

        int new_server_socket = accept(server_socket, (struct sockaddr *)&client_addr, &length);
        if (new_server_socket < 0)
        {
            printf("Server Accept Failed!\n");
            break;
        }

        my_message mm;
        mm.set_startedtime(time);
        mm.set_version(version);
        mm.set_configuredcapacity(config);
        mm.set_dfsused(dfs);
        mm.set_filenum(file);
        mm.set_replicatedfilesnum(rep);
        mm.set_blocknum(block);
        mm.set_livednodenum(live);
        mm.set_decommissioningnodenum(de);
        file += 1;
        rep += 1;
        block += 1;
        live += 1;
        de += 1;

        int len = mm.ByteSize() + 4;
        char *buffer = new char[len];

        google::protobuf::io::ArrayOutputStream arrayOut(buffer, len);
        google::protobuf::io::CodedOutputStream codedOut(&arrayOut);

        codedOut.WriteVarint32(mm.ByteSize());

        //write protobuf my_message mm to CodedOutputStream
        mm.SerializeToCodedStream(&codedOut);

        if (send(new_server_socket, buffer, len, 0) < 0)
        {
            printf("Send Failed\n");
            break;
        }

        close(new_server_socket);
        delete buffer;
    }
    close(server_socket);
    return 0;
}

makefile文件

prom=server
obj=server.cpp infor.pb.cc
$(prom) : $(obj)
	g++ $(obj) -o ./$@ -g -Wall -lpthread -lprotobuf -std=c++11 
clean:
	rm -rf ./build/$(prom)

生成server可执行文件，至此服务端的准备工作完成

4、客户端的准备工作
idea中安装我的目录结构

infor.proto文件

syntax = "proto2";
option java_package = "com.protobuftest.protobuf";
option java_outer_classname = "CodedInputStream";

message my_message{
    required string startedTime =1;
    required string version=2;
    required double configuredCapacity=3;
    required double dfsUsed =4;
    required int32 fileNum=5;
    required int32 replicatedFilesNum =6;
    required int32 blockNum =7;
    required int32 livedNodeNum =8;
    required int32 decommissioningNodeNum=9;
}

5、java的主代码，代码中ip地址改为自己的地址和端口

package com.protobuftest.protobuf;

import java.io.IOException;
import java.io.InputStream;
import java.net.Socket;

public class Client {
    public static final String IP_ADDR = "139.196.53.139";    //server ip
    public static final int PORT = 8888;    //port

    public static void main(String[] args) throws InterruptedException {
        System.out.println("client starting...");

        do {
            Thread.sleep(1000);
            Socket socket = null;
            try {
                socket = new Socket(IP_ADDR, PORT);

                InputStream input = socket.getInputStream();
                try{
                    // 反序列化
                    CodedInputStream.my_message mm = CodedInputStream.my_message.parseDelimitedFrom(input);

                    System.out.println("服务器端返回过来的是: ");
                    System.out.println("startedTime:" + mm.getStartedTime());
                    System.out.println("version:" + mm.getVersion());
                    System.out.println("configuredCapacity:" + mm.getConfiguredCapacity());
                    System.out.println("dfsUsed:" + mm.getDfsUsed());
                    System.out.println("fileNum:" + mm.getFileNum());
                    System.out.println("replicatedFilesNum:" + mm.getReplicatedFilesNum());
                    System.out.println("blockNum:" + mm.getBlockNum());
                    System.out.println("livedNodeNum:" + mm.getLivedNodeNum());
                    System.out.println("decommissioningNodeNum:" + mm.getDecommissioningNodeNum());
                } catch(Exception e)
                {
                    System.out.println(e.toString());
                    System.out.println("catch e");
                    break;
                }
                input.close();
            } catch (Exception e) {
                System.out.println("客户端异常:" + e.getMessage());
            } finally {
                if (socket != null) {
                    try {
                        socket.close();
                    } catch (IOException e) {
                        socket = null;
                        System.out.println("客户端 finally 异常:" + e.getMessage());
                    }
                }
            }
        }while(false);
    }
}

6、window端也要准备编译protocbuf的环境，但不需要像服务端那么麻烦，只需要protoc.exe就可以了
进到官网下载即可

7、对infor.proto文件进行编译，进到与infor.proto同一夹子下再进行编译

D:\download\protoc-3.19.1-win64\bin\protoc.exe --java_out=./ infor.proto

编译出来的java文件会放入对应的包中

8、文件中可能还需要加入

进到官网

https://mvnrepository.com/

点击下载即可

添加jar包即可
至此全部的环境已经准备完成
9、启动服务
先启动服务端的可执行文件
再运行java代码
之后java收到了服务端的数据