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2024年外贸新兴市场有哪些 | 箱讯科技国际贸易平台

夏沐沐 2024-01-19 阅读 14

一、Protocol buffers 是什么?

优点是更小更快;且对于数据扩展兼容性好,因为新增数据字段不影响旧字段解析;语义清晰且学习门槛低;

如果想详细了解可戳这:protobuf.dev

二、怎么使用

这里先介绍如何将.proto文件转换成.pbobjc.h和.pbobjc.m文件,然后导入到项目中,并实现pbData转pbModel,pbModel转pbData

切记一定要安装3.0以上的版本,才支持OC,而且功能更好用;

推荐使用Homebrew来安装:

brew install automake 
brew install libtool 
brew install protobuf

安装后check一下,可输出当前安装版本

protoc --version

准备好这些后,

  1. 集成集成protobuf库
 pod 'Protobuf'
  1. 将.proto文件转换成.pbobjc.h和.pbobjc.m文件

先cd到.proto文件所在目录,然后执行如下操作,会在同级目录里生成.pbobjc.h和.pbobjc.m文件;

protoc --proto_path=. --objc_out=. xxxx.proto

注意: 这里生成的.pbobjc.h和.pbobjc.m文件无法直接导入项目中使用,你会发现文件中一堆MRC的代码;

参考如下:iOS 组件中设置文件支持MRC

至此,项目build是可以success的,接下来是如何使用

  1. pbModel转pbData

pb提供了一个data方法,可将使用上面步骤导入项目的pbobjc类也可以理解成model类转换成data

/**
 * Serializes the message to an NSData.
 *
 * If there is an error while generating the data, nil is returned.
 *
 * @note This value is not cached, so if you are using it repeatedly, cache
 *       it yourself.
 *
 * @note In DEBUG ONLY, the message is also checked for all required field,
 *       if one is missing, nil will be returned.
 *
 * @return The binary representation of the message.
 **/
- (nullable NSData *)data;

如下示例,xxpbModel就是代表一个pbobjc类

NSData *pbData = [xxpbModel data];
  1. pbData转pbModel

pb提供了一个init方法来将一个data映射成pbobjc类

/**
 * Initializes an instance by parsing the data. This method should be sent to
 * the generated message class that the data should be interpreted as. If
 * there is an error the method returns nil and the error is returned in
 * errorPtr (when provided).
 *
 * @note In DEBUG builds, the parsed message is checked to be sure all required
 *       fields were provided, and the parse will fail if some are missing.
 *
 * @note The errors returned are likely coming from the domain and codes listed
 *       at the top of this file and GPBCodedInputStream.h.
 *
 * @param data     The data to parse.
 * @param errorPtr An optional error pointer to fill in with a failure reason if
 *                 the data can not be parsed.
 *
 * @return An initialized instance of the generated class.
 **/
- (nullable instancetype)initWithData:(NSData *)data 
                                error:(NSError **)errorPtr;

如下示例,生成一个pbobjc类对象或者说一个pbModel
XXPbModel 是一个pbobjc类名

NSError *error;
XXPbModel *pbModel = [[XXPbModel alloc] initWithData:data error:&error];
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