Android Studio报错：ERROR: Failed to resolve: com.android.support:appcompat-v7:28.0.+

Android Studio报错：ERROR: Failed to resolve: com.android.support:appcompat-v7:28.0.+

今天新导入一个Project项目，上来就报错找不到类库，Google狠起来自己的儿子都编译不过了么？吐血，如下：

ERROR: Failed to resolve: com.android.support:appcompat-v7:28.0.+
Add Google Maven repository and sync project
Show in Project Structure dialog
Affected Modules: app

ERROR: Failed to resolve: com.android.support:recyclerview-v7:28.0.0
Add Google Maven repository and sync project
Show in Project Structure dialog
Affected Modules: app

ERROR: Failed to resolve: com.android.support.test.espresso:espresso-core:2.2.2
Add Google Maven repository and sync project
Show in Project Structure dialog
Affected Modules: app

尝试各种Clear、Rebuild无果后放弃了，还得去StackOverflow寻找良方，果然不负众望，找到了答案：
Failed to resolve: com.android.support:appcompat-v7:28.0
项目级Gradle中repositories的jcenter()下一行添加如下maven代码即可：

allprojects {
    repositories {
        jcenter()
        maven {// here we go!!
            url 'https://maven.google.com'
        }
    }
}

再编译，完美运行。