使用Google ProtoBuff完成RPC服务的通信

需求：
使用netty完成一个RPC服务器的编写和调用，在通信的过程中使用protobuff来传递数据
前提：
protobuff官网：https://developers.google.com/protocol-buffers/ (需要翻墙)
困惑：
RPC和RMI的区别？
      原理都是类似的，只是RMI是使用Java编写的不能跨语言，RPC是支持跨语言的
RPC和webservice的区别
      webservice 使用http协议进行通信，RPC使用socket进行通信，socket效率更高
      webservice使用xml进行数据通信,xml最臭名昭著的就是比较占空间，而且遍历和查找很不方法,rpc使用体积更小，速度更快，解析更强的框架进行数据传递(数据的压缩比决定了数据的大小),日入使用Google protobuff 、grpc、apache thrift等。
protobuf 的学习过程
1. 首先找到官网学习一下什么是protobuf

2. 下载protobuf的编译器(https://github.com/google/protobuf)

3. 配置protobuff编译器的环境变量

4. 阅读protobuff的文档(https://developers.google.com/protocol-buffers/docs/javatutorial)

编写protobuff程序主要有散步

使用Google ProtoBuff完成RPC服务的通信

5. protobuff解决的问题

使用Google ProtoBuff完成RPC服务的通信

netty集成protobufff完成RPC的方法调用

实现步骤:

1. 进入protobuff需要jar包

使用Google ProtoBuff完成RPC服务的通信

2. 编写protobuff的.proto文件(该文件我们也成为idl（interface description language）文件)

[Java] 纯文本查看 复制代码

syntax = "proto2";

package com.baidu.netty.proto;

option java_package = "com.baidu.netty.sixExample";

option java_outer_classname = "TeacherData";

option optimize_for=SPEED;

message Teacher

{

required int32 id = 1;

optional string name = 2;

enum GenderType

{

MALE = 0;

FEMALE = 1;

}

message Student

{

required int32 id = 1;

optional string name = 2;

optional string email = 3;

optional GenderType gender = 4 [default = MALE];

}

}

3. 使用protobuff的编译器生产代码(几乎所有的RPC框架都有代码生成框架)

protoc --java_out=代码存放的目录 .proto文件存放的位置

4. 简单测试生成的类是否能够使用

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<font style="color:rgb(77, 77, 77)"><font face="""><font style="font-size:16px">package com.baidu.netty.sixExample;

public class TestTearcher {

public static void main(String[] args) throws Exception{

TeacherData.Teacher teacher = TeacherData.Teacher.newBuilder().setId(1).setName("老徐").build();

System.out.println(teacher.getName());

//对象的***

byte[] temp = teacher.toByteArray();

//对象的反***

TeacherData.Teacher teacher1 = TeacherData.Teacher.parseFrom(temp);

System.out.println(teacher1.getName());

}

}

使用Google ProtoBuff完成RPC服务的通信

5. 编写netty的服务器端启动程序

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<font style="color:rgb(77, 77, 77)"><font face="""><font style="font-size:16px">package com.baidu.netty.sixExample;

import io.netty.bootstrap.ServerBootstrap;

import io.netty.channel.ChannelFuture;

import io.netty.channel.EventLoopGroup;

import io.netty.channel.nio.NioEventLoopGroup;

import io.netty.channel.socket.nio.NioServerSocketChannel;

public class MyServer {

public static void main(String[] args) throws Exception{

EventLoopGroup bossGroup = new NioEventLoopGroup();

EventLoopGroup workerGroup = new NioEventLoopGroup();

try {

ServerBootstrap bootstrap = new ServerBootstrap();

bootstrap.group(bossGroup,workerGroup).channel(NioServerSocketChannel.class).childHandler(new MyServerInitializer());

ChannelFuture future = bootstrap.bind(8899).sync();

future.channel().closeFuture().sync();

}finally {

bossGroup.shutdownGracefully();

workerGroup.shutdownGracefully();

}

}

6. 编写服务器端初始化类

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<font style="color:rgb(77, 77, 77)"><font face="""><font style="font-size:16px">package com.baidu.netty.sixExample;

import io.netty.channel.ChannelInitializer;

import io.netty.channel.ChannelPipeline;

import io.netty.channel.socket.SocketChannel;

import io.netty.handler.codec.protobuf.ProtobufDecoder;

import io.netty.handler.codec.protobuf.ProtobufEncoder;

import io.netty.handler.codec.protobuf.ProtobufVarint32FrameDecoder;

import io.netty.handler.codec.protobuf.ProtobufVarint32LengthFieldPrepender;

public class MyServerInitializer extends ChannelInitializer<SocketChannel> {

@Override

protected void initChannel(SocketChannel ch) throws Exception {

ChannelPipeline pipeline = ch.pipeline();

pipeline.addLast(new ProtobufVarint32FrameDecoder());

pipeline.addLast(new ProtobufDecoder(TeacherData.Teacher.getDefaultInstance()));

pipeline.addLast(new ProtobufVarint32LengthFieldPrepender());

pipeline.addLast(new ProtobufEncoder());

pipeline.addLast(new MyServerHandler());

}

}

7. 编写服务器端处理类

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<font style="color:rgb(77, 77, 77)"><font face="""><font style="font-size:16px">package com.baidu.netty.sixExample;

import io.netty.channel.ChannelHandlerContext;

import io.netty.channel.SimpleChannelInboundHandler;

public class MyServerHandler extends SimpleChannelInboundHandler<TeacherData.Teacher> {

@Override

protected void channelRead0(ChannelHandlerContext ctx, TeacherData.Teacher msg) throws Exception {

System.out.println(msg.getName());

System.out.println(msg.getId());

}

}

8. 编写客户端启动类

[AppleScript] 纯文本查看 复制代码

<font style="color:rgb(77, 77, 77)"><font face="""><font style="font-size:16px">package com.baidu.netty.sixExample;

import io.netty.bootstrap.Bootstrap;

import io.netty.channel.Channel;

import io.netty.channel.ChannelFuture;

import io.netty.channel.EventLoopGroup;

import io.netty.channel.nio.NioEventLoopGroup;

import io.netty.channel.socket.nio.NioSocketChannel;

public class MyClient {

public static void main(String[] args) throws Exception{

EventLoopGroup client = new NioEventLoopGroup();

try {

Bootstrap bootstrap = new Bootstrap();

bootstrap.group(client).channel(NioSocketChannel.class).handler(new MyClientInitializer());

ChannelFuture future = bootstrap.connect("localhost",8899).sync();

Channel channel = future.channel();

TeacherData.Teacher teacher = TeacherData.Teacher.newBuilder().setName("老徐").setId(1).build();

channel.writeAndFlush(teacher);

channel.closeFuture().sync();

}finally {

client.shutdownGracefully();

}

}

9. 编写客户端初始化类

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<font style="color:rgb(77, 77, 77)"><font face="""><font style="font-size:16px">package com.baidu.netty.sixExample;

import io.netty.channel.ChannelInitializer;

import io.netty.channel.ChannelPipeline;

import io.netty.channel.socket.SocketChannel;

import io.netty.handler.codec.protobuf.ProtobufDecoder;

import io.netty.handler.codec.protobuf.ProtobufEncoder;

import io.netty.handler.codec.protobuf.ProtobufVarint32FrameDecoder;

import io.netty.handler.codec.protobuf.ProtobufVarint32LengthFieldPrepender;

public class MyClientInitializer extends ChannelInitializer<SocketChannel> {

@Override

protected void initChannel(SocketChannel ch) throws Exception {

ChannelPipeline pipeline = ch.pipeline();

pipeline.addLast(new ProtobufVarint32FrameDecoder());

pipeline.addLast(new ProtobufDecoder(TeacherData.Teacher.getDefaultInstance()));

pipeline.addLast(new ProtobufVarint32LengthFieldPrepender());

pipeline.addLast(new ProtobufEncoder());

}

}

10. 测试客户端向服务器端发送对象