ProtoBuf学习之"Hello World"

1、下载对应的包文件，比如我这里下载的是protoc-3.6.1-win32.zip，解压后将其bin路径加入到系统的PATH环境变量中；

      在cmd窗口中执行protoc --version来检查protoc是否正确安装；

2、编写protoBuf文件：

syntax = "proto2";

package protocol;

option java_package = "com.demo.prototest";
option java_outer_classname = "BaseRequestProto";

message RequestProtocol {
    required int32 requestId = 2;
    required string regMsg = 1;
}

syntax = "proto2";

package protocol;

option java_package = "com.demo.prototest";
option java_outer_classname = "BaseResponseProto";

message ResponseProtocol {
    required int32 responseId = 2;
    required string resMsg = 1;
}

3、编译proto文件：

          protoc --java_out=/dev BaseRequestProto.proto BaseResponseProto.proto

protoc 命令将刚才定义的协议格式转换为 Java 代码，并生成在 /dev 目录。

4、引入POM文件：

<dependency>
    <groupId>com.google.protobuf</groupId>
    <artifactId>protobuf-java</artifactId>
    <version>3.4.0</version>
</dependency>

5、实现protoBuf编码解码测试代码：

public static void main(String[] args) throws InvalidProtocolBufferException {
    BaseRequestProto.RequestProtocol protocol = BaseRequestProto.RequestProtocol.newBuilder()
            .setRequestId(123)
            .setRegMsg("hello, protobuf and world")
            .build();

    byte[] encode = encode(protocol);

    BaseRequestProto.RequestProtocol parseFrom = decode(encode);

    System.out.println(protocol.toString());
    System.out.println(protocol.toString().equals(parseFrom.toString()));
}

public static byte[] encode(BaseRequestProto.RequestProtocol protocol){
    return protocol.toByteArray() ;
}

public static BaseRequestProto.RequestProtocol decode(byte[] bytes) throws InvalidProtocolBufferException {
    return BaseRequestProto.RequestProtocol.parseFrom(bytes);
}