Mac下安裝protobuf以及簡單使用

1.安裝

brew install protobuf

2.查看安裝版本

➜  protobuf git:(dev) ✗ protoc --version
libprotoc 3.4.0
➜  protobuf git:(dev) ✗

3.生成Prtobuf文件

➜  java git:(dev) ✗ protoc --java_out=./ com/test/frame/zookeeper/protobuf/SubscribeReq.proto
➜  java git:(dev) ✗ pwd
/Users/guanguan/study/frame/zookeeper/src/main/java
➜  java git:(dev) ✗

4.若是遇到如下問題

➜  protobuf git:(dev) ✗ sudo protoc --java_out=./ SubscribeReq.proto                  
[libprotobuf WARNING google/protobuf/compiler/parser.cc:546] No syntax specified for the proto file: SubscribeReq.proto. Please use 'syntax = "proto2";' or 'syntax = "proto3";' to specify a syntax version. (Defaulted to proto2 syntax.)

解決方案，將syntax ="proto2"或者syntax="proto3"放到.proto文件前面便可解決如（SubscribeReq.proto）

syntax = "proto2";

package com.test.frame.zookeeper.protobuf;
option java_package="com.test.frame.zookeeper.protobuf";
option java_outer_classname="SubscribeReqProto";


message SubscribeReq{
   required int32 subReqID=1;
   required string userName=2;
   required string productName=3;
   required string address=4;


}

5.pom.xml文件中增長依賴

<!-- https://mvnrepository.com/artifact/com.google.protobuf/protobuf-java -->
        <dependency>
            <groupId>com.google.protobuf</groupId>
            <artifactId>protobuf-java</artifactId>
            <version>3.4.0</version>
        </dependency>

6.測試編解碼效果TestSubcribeReq.java

package com.test.frame.zookeeper.protobuf;

import com.google.protobuf.InvalidProtocolBufferException;

/**
 * TestSubscribeReqProto class
 *
 * @author guanhuifang
 * @date 2017/10/30 下午4:35
 **/
public class TestSubscribeReqProto {


    /**
     * 編碼encode
     *
     * 將SubscribeReq類型的轉爲字節數組
     * @param req
     * @return
     */
    private static byte[] encode(SubscribeReqProto.SubscribeReq req){
        /**
         * 編碼時經過調用SubscribeReqProto.SubscribeReq實例的toByteArray便可將SubscribeReq編碼爲byte數組
         */
        return req.toByteArray();
    }


    /**
     * 解碼
     * 將字節數組轉換爲SubscribeReq類型
     * @param body
     * @return
     * @throws InvalidProtocolBufferException
     */
    private static SubscribeReqProto.SubscribeReq decode(byte[] body) throws InvalidProtocolBufferException {
        /**
         * 解碼時經過調用SubscribeReqProto.SubscribeReq實例的靜態方法parseForm將二進制byte數組解碼爲原始的對象
         */
        return SubscribeReqProto.SubscribeReq.parseFrom(body);
    }

    private static SubscribeReqProto.SubscribeReq createSubscribeReq(){
        /**
         * 經過靜態方法newBuilder建立Builder實例，經過Builder構建器對SubscribeReq的屬性進行設置
         */
        SubscribeReqProto.SubscribeReq.Builder builder= SubscribeReqProto.SubscribeReq.newBuilder();
        builder.setSubReqID(1);
        builder.setUserName("Gholly");
        builder.setProductName("hh");

        builder.setAddress("Shenzhen");
        return builder.build();

    }

    public static void main(String[] args) throws InvalidProtocolBufferException {
        SubscribeReqProto.SubscribeReq req=createSubscribeReq();
        System.out.println("encode before:"+req.toString());
        SubscribeReqProto.SubscribeReq req2= decode(encode(req));
        System.out.println("after decode:"+req.toString());
        System.out.println(req2.equals(req));

    }



}

運行結果爲：

encode before:subReqID: 1
userName: "Gholly"
productName: "hh"
address: "Shenzhen"

after decode:subReqID: 1
userName: "Gholly"
productName: "hh"
address: "Shenzhen"

true

Process finished with exit code 0

說明編解碼先後數據是同樣的