Google Protobuf文件转Java文件

Protobuf协议目前分两个版本 protobuf v3 与protobuf v2两个版本
项目中使用Protobuf作为数据传输，使用AndroidStudio工具批量编译protobuf文件比较简单。

这里写图片描述

开始配置环境
protobuf文件

option java_package = "com.daycodeday.test";
option java_outer_classname = "MtmColWrapper";

message MtmCol {
optional    uint32      colnamelength           = 1;
required    string      colname             = 2;

optional    uint32      coltype             = 3;

optional    uint32      coltypestringlength     = 4;
optional    string      coltypestring           = 5;

optional    uint32      length              = 6;

optional    uint32      precision           = 7;
optional    uint32      scale               = 8;
optional    uint32      nullable            = 9;            

}

项目根目录配置build.gradle

    dependencies {
        classpath 'com.android.tools.build:gradle:2.3.3'
        // protobuf支持版本
        classpath 'com.google.protobuf:protobuf-gradle-plugin:0.8.0'
      
    }

modle根目录配置build.gradle

//依赖支持
apply plugin: 'com.google.protobuf'

//指定文件目录
  sourceSets {
        main {

            proto {
             //main目录新建proto目录
                srcDir 'src/main/proto'
                include '**/*.proto'
            }
            java {
                srcDir 'src/main/java'
            }
        }
    }

//依赖库
compile 'com.google.protobuf:protobuf-java:2.5.0'
compile 'com.google.protobuf:protoc:2.5.0'

//构建task
protobuf {
    protoc {
        artifact = 'com.google.protobuf:protoc:2.5.0'
    }

    generateProtoTasks {
        all().each { task ->
            task.builtins {
                remove java
            }
            task.builtins {
                java {}
                // Add cpp output without any option.
                // DO NOT omit the braces if you want this builtin to be added.
                cpp {}
            }
        }
    }
    //生成目录
    generatedFilesBaseDir = "$projectDir/src/generated"
}

我使用依赖库是 2.5 ，如果是3.0以上依赖库的需要定义下协议头

3.0 头部开始加上
syntax = "proto3";
2.0 头部加上
syntax = "proto2";

下面是完整的gradle文件

apply plugin: 'com.android.application'
apply plugin: 'com.google.protobuf'

android {
    compileSdkVersion 25
    buildToolsVersion "25.0.3"
    defaultConfig {
        applicationId "com.daycodeday.myapplication"
        minSdkVersion 15
        targetSdkVersion 25
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
    sourceSets {
        main {

            proto {
                srcDir 'src/main/proto'
                include '**/*.proto'
            }
            java {
                srcDir 'src/main/java'
            }
        }
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })
    compile 'com.android.support.constraint:constraint-layout:1.0.2'
    testCompile 'junit:junit:4.12'
    compile 'com.google.protobuf:protobuf-java:3.1.0'
    compile 'com.google.protobuf:protoc:3.1.0'
}
protobuf {
    protoc {
        artifact = 'com.google.protobuf:protoc:3.1.0'
    }

    generateProtoTasks {
        all().each { task ->
            task.builtins {
                remove java
            }
            task.builtins {
                java {}
                // Add cpp output without any option.
                // DO NOT omit the braces if you want this builtin to be added.
                cpp {}
            }
        }
    }
    //生成目录
    generatedFilesBaseDir = "$projectDir/src/generated"
}