Could not find com.android.tools.build:gradle:3.0.1

更新gradle后运行应用，报错。 
解决办法： 

提示找不到gradle：3.0.1 
在顶层build.gradle 中，可以看到build.gradle的配置：

buildscript {
    repositories {
        jcenter()
     }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.0.1'

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

...

需要做的修改：添加maven仓库，即在repositories中添加

maven {
            url 'https://maven.google.com'
        }

修改后

buildscript {
    repositories {
        jcenter()
        maven {
            url 'https://maven.google.com'
        }
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.0.1'

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

这里可以对比一下2.2.3的配置

buildscript {
    repositories {
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:2.2.3'

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}
...