how to create corners of container in flutter code example

Example 1: flutter container rounded corners

Container(
  decoration: BoxDecoration(
    border: Border.all(
      color: Colors.red[500],
    ),
    borderRadius: BorderRadius.all(Radius.circular(20))
  ),
  child: ...
)

Example 2: flutter container rounded corners

new Center(    child: new Container(      width: 200.0,      height: 200.0,      color: Colors.white,      child: new Container(        decoration: new BoxDecoration(          border: new Border.all(              color: Colors.green,              width: 5.0,              style: BorderStyle.solid          ),          borderRadius: new BorderRadius.all(new Radius.circular(20.0)),          image: new DecorationImage(              image: new AssetImage('assets/images/JL-Logo-150.png'),          )        ),      ),    ),  );