Protobuf —— .proto文件详解

说明

     proto文件扩展名称为”.proto“，可以使用import包含另一个.proto文件。
 

字段限制

     required —— 必须赋值的字符
     optional —— 可有可无的字段，可以使用[default = xxx]配置默认值
     repeated —— 可重复变长字段，类似数组
 

类型

• 系统默认值：

     string默认为空字符串；

     bool默认为false；

     数值默认为0；

     enum默认为第一个元素

举例

• 小例
       如下，”proto2″语法类型、VsQtProtobuf包名、Persion为消息名、消息内部定义了4个带有默认值得项 – 1个必填和3个选填、性别枚举、消息Grade和Language。
       注意:嵌套的Grade和Language声明方式不一样。在代码里解析也不一样。首先Grade声明的是optional那么直接按常规使用即可；Language声明方式为repeaed,这样的话解析时必须循环解析。
  

  
  
  
  
  
  

// 发送端 void ProtobufTest_A::on_sendButton_A_clicked() { // 单播 // qint64 len = mSocket->writeDatagram(ui->textEdit->toPlainText().toUtf8(),QHostAddress("192.168.137.1"),6677); //组播ip地址范围：224.0.0.0-239.255.255.255 //qint64 len = mSocket->writeDatagram(ui->textEdit->toPlainText().toUtf8(),QHostAddress("224.0.0.100"),6677); //广播 //qint64 len = mSocket->writeDatagram(ui->textEdit->toPlainText().toUtf8(), QHostAddress::Broadcast, 6677); // 序列化前初始值 VsQtProtobuf::Persion protobufTest; protobufTest.set_id(ui.port_A->text().toInt()); VsQtProtobuf::Persion::Language *language = protobufTest.add_language(); // 获取长度 unsigned short protobufTestLength = protobufTest.ByteSize() + 1; // 存储序列化buf char *buf = nullptr; buf = new char[protobufTestLength]; memset(buf, 0, protobufTestLength); // 序列化 protobufTest.SerializeToArray(buf, protobufTestLength); // udp发送 UdpSocket_A->writeDatagram(buf, protobufTestLength, QHostAddress(ip_B), port_B); // 释放序列化buf if (buf) delete buf; buf = nullptr; } // 接收端 void ProtobufTest_B::readyRead() { QByteArray array; array.resize(UdpSocket_B->bytesAvailable()); if (array.size()) { UdpSocket_B->readDatagram(array.data(), array.size()); VsQtProtobuf::Persion protobufTest; protobufTest.ParseFromArray(array.data(), array.size()); ui.receiveTxt_B->append("id:\t" + QString::number(protobufTest.id())); ui.receiveTxt_B->append("name:\t" + QString(protobufTest.name().c_str())); ui.receiveTxt_B->append("age:\t" + QString::number(protobufTest.age())); if (::VsQtProtobuf::Persion_Sex::Persion_Sex_man == protobufTest.sex()) ui.receiveTxt_B->append("sex:\t"+QString::fromLocal8Bit("男")); else if (::VsQtProtobuf::Persion_Sex::Persion_Sex_woman == protobufTest.sex()) ui.receiveTxt_B->append("sex:\t" + QString::fromLocal8Bit("女")); else if (::VsQtProtobuf::Persion_Sex::Persion_Sex_taiguo == protobufTest.sex()) ui.receiveTxt_B->append("sex:\t" + QString::fromLocal8Bit("男女")); ui.receiveTxt_B->append("address:\t" + QString(protobufTest.address().c_str())); VsQtProtobuf::Persion::Grade grade =protobufTest.grade(); ui.receiveTxt_B->append("grade-chinese:\t" + QString::number(grade.chinese())); ui.receiveTxt_B->append("grade-english:\t" + QString::number(grade.english())); // 声明方式"repeaed"的解析过程 int indexs = protobufTest.language_size(); for (unsigned int index = 0; index < indexs; ++index) { bool language_chinese = protobufTest.language(index)._chinese(); if (language_chinese) ui.receiveTxt_B->append("language-chinese:\tyes"); else ui.receiveTxt_B->append("language-chinese:\tno"); bool language_english = protobufTest.language(index)._english(); if (language_english) ui.receiveTxt_B->append("language-english:\tyes"); else ui.receiveTxt_B->append("language-english:\tno"); ui.receiveTxt_B->append("\n"); } } } 

• 结果
  
  
  

关注

笔者 – jxd

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