java項目使用protobuf學習筆記

1. 添加依賴

   <dependency>
       <groupId>com.google.protobuf</groupId>
       <artifactId>protobuf-java</artifactId>
       <version>3.12.4</version>
   </dependency>
              

2. maven插件配置（pom.xml）

   <build>
       <extensions>
           <extension>
               <groupId>kr.motd.maven</groupId>
               <artifactId>os-maven-plugin</artifactId>
               <version>1.6.2</version>
           </extension>
       </extensions>
       <plugins>
           <plugin>
               <groupId>org.xolstice.maven.plugins</groupId>
               <artifactId>protobuf-maven-plugin</artifactId>
               <version>0.6.1</version>
               <extensions>true</extensions>
               <configuration>
                   <protoSourceRoot>${project.basedir}/src/main/proto</protoSourceRoot>
                   <outputDirectory>${project.build.directory}/generated-sources/protobuf/java</outputDirectory>
                   <!--設定是否生成java檔案之前清空outputDirectory的檔案，預設值為true，設定false時會覆寫同名檔案-->
                   <clearOutputDirectory>true</clearOutputDirectory>
                   <protocArtifact>com.google.protobuf:protoc:3.12.4:exe:${os.detected.classifier}</protocArtifact>
                   <pluginId>grpc-java</pluginId>
               </configuration>
               <executions>
                   <execution>
                       <goals>
                           <goal>compile</goal>
                           <goal>compile-custom</goal>
                       </goals>
                   </execution>
               </executions>
           </plugin>
       </plugins>
   </build>
              

3. 定義proto檔案

   syntax = "proto3";
   option java_package = "com.yicj.study.proto" ;
   option java_outer_classname = "PersonModel" ;
   message Person{
       int32 id = 1 ;
       string name = 2 ;
       string email = 3 ;
   }
              

4. 找到plugins中的protobuf點選protobuf:compile生成對應的java檔案（target/generated-sources/protobuf/java）
5. 将PersonModel檔案移動到源碼包下com.yicj.study.proto中
6. 編寫單元測試

   public class PersonModelTest {
       @Test
       public void hello() throws InvalidProtocolBufferException {
           PersonModel.Person forezp = PersonModel.Person.newBuilder()
                   .setId(1).setName("forezp").setEmail("[email protected]").build() ;
           for (byte b : forezp.toByteArray()){
               System.out.print(b);
           }
           String s = CommonUtil.base64Encode(forezp.toByteArray());
           System.out.println();
           System.out.println("====================> " + s);
           System.out.println();
           log.info("\n" + "bytes長度" + forezp.toByteString().size());
           log.info("========forezp Byte 結束==========");
           log.info("========forezp 反序列化生成對象開始======");
           PersonModel.Person forezpCopy = PersonModel.Person.parseFrom(forezp.toByteArray()) ;
           log.info(forezpCopy.toString());
           log.info("====== forezp 反系列化生成對象結束=======");
       }
   }