打Jar包的几种方式：

def SDK_BASENAME = "Sdk";//打包后名字
def SDK_VERSION = "_V1.0";//${defaultConfig.versionName}
def sdkDestinationPath = "build";//保存目录
def zipFile = file('build/intermediates/bundles/release/classes.jar')

task deleteBuild(type: Delete) {//删除jar包
    delete sdkDestinationPath + "/" + SDK_BASENAME + SDK_VERSION + ".jar"
}

task makeJar(type: Jar) {//生成jar
    from zipTree(zipFile)
    from fileTree(dir: 'src/main', includes: ['assets/**'])
    baseName = SDK_BASENAME + SDK_VERSION
    destinationDir = file(sdkDestinationPath)//目的地
}

makeJar.dependsOn(deleteBuild, build)
//在终端执行生成JAR包
// gradlew makeJar

def SDK_BASENAME = "Sdk";//打包后名字
def SDK_VERSION = "_V1.0";//${defaultConfig.versionName}
def SDK_NAME = SDK_BASENAME + SDK_VERSION + ".jar";
//Copy类型
task makeJar(type: Copy) {
    //删除存在的
    delete 'build/libs/' + SDK_NAME
    //设置拷贝的文件
    from('build/intermediates/bundles/release/')
    //打进jar包后的文件目录
    into('build/libs/')
    //将classes.jar放入build/libs/目录下
    //include ,exclude参数来设置过滤
    //（我们只关心classes.jar这个文件）
    include('classes.jar')
    //重命名
    rename('classes.jar', SDK_NAME)
}
makeJar.dependsOn(build)
//在终端执行生成JAR包
//gradlew makeJar

task clearJar(type: Delete) {
    delete 'libs/sdk.jar'
}
task makeJar(type: org.gradle.api.tasks.bundling.Jar) {
    //指定生成的jar名
    baseName 'sdk'
    //从哪里打包class文件
    from('build/intermediates/classes/debug/org/cmdmac/cloud/pluginsdk/')
    //打包到jar后的目录结构
    into('build/libs/')
    //去掉不需要打包的目录和文件
    exclude('test/', 'BuildConfig.class', 'R.class')
    //去掉R$开头的文件
    exclude { it.name.startsWith('R$'); }
}
makeJar.dependsOn(clearJar, build)
//在终端执行生成JAR包
//gradlew makeJar

def SDK_BASENAME = "Sdk";//打包后名字
def SDK_VERSION = "_V1.0";//${defaultConfig.versionName}
def SDK_NAME = SDK_BASENAME + SDK_VERSION + ".jar";
def zipFile = file('build/intermediates/bundles/release/classes.jar')
def sdkDestinationPath = "build/libs/";//保存目录
task makeJar(type: Jar) {//生成jar
    delete 'build/libs/' + SDK_NAME
    from zipTree(zipFile)
    from fileTree(dir: 'src/main', includes: ['assets/**'])
    from(project.zipTree('libs/xutils-3.3.4.jar'))
    from(project.zipTree('libs/glide-3.7.0.jar'))
    from(project.zipTree('libs/xutils-3.3.4.jar'))
    baseName = SDK_BASENAME + SDK_VERSION
    destinationDir = file(sdkDestinationPath)//目的地
}
makeJar.dependsOn(build)

选择以上任意一段代码，然后使用以下任意一种方法打Jar包。

方式一：

方式二：

Jar包混淆：

由于这个项目使用了NDK，所以以下NDK配置请略过。

android {
    compileSdkVersion versions.compileSdk
    buildToolsVersion versions.buildTools

    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_7
        targetCompatibility JavaVersion.VERSION_1_7
    }
    defaultConfig {
        versionName project.version
        minSdkVersion versions.minSdk
        targetSdkVersion versions.targetSdk
        consumerProguardFiles 'proguard-rules.pro'
        testInstrumentationRunner 'android.support.test.runner.AndroidJUnitRunner'
        externalNativeBuild {
            ndkBuild {
                arguments "NDK_DEBUG=${isDebugBuild() ? '1' : '0'}"
            }
        }
    }
    externalNativeBuild {
        ndkBuild {
            path 'src/main/c/Android.mk'
        }
    }

    sourceSets {
        main {
            //你的源码目录
            jniLibs.srcDirs 'src/main/libs'
        }
    }
    repositories {
        flatDir {
            dirs 'src/main/libs'
        }
    }
    buildTypes {
        release {
            minifyEnabled false//混淆打包
            shrinkResources true//去掉不用资源
//            signingConfig signingConfigs.release
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }

    }
}

混淆配置需要根据自己项目情况酌情配置，配置文件可以去SDK目录拷贝。