问DexGuard在java项目中的应用

EN

apply plugin: 'com.android.application'

apply plugin: 'java'

apply plugin: 'com.github.johnrengelman.shadow'

buildscript {
    repositories { 
        jcenter()
        flatDir dirs: 'DexGuard/lib'
    }
}
    dependencies {
        classpath 'com.github.jengelman.gradle.plugins:shadow:1.2.2'
        classpath ':dexguard'
    }
}

apply plugin: 'java'
apply plugin: 'com.github.johnrengelman.shadow'

repositories {
    mavenCentral()
}

dependencies {
    compile fileTree(dir: 'libs', include: '**/*.jar')
}

sourceSets {
    main {
        java.srcDirs = ['src']
    }
}

shadowJar {
...
}

task sdkDexguard(type: com.saikoa.dexguard.gradle.DexGuardTask) {
    configuration 'dexguard.txt'
    injars  'build/classes'
    injars  'libs'
    outjars 'build/application.apk'
}

Could not find property 'com' on root project