如何在AngularJS中共享一个控制器的$scope变量?

I have this:

我有这个:

app.controller('foo1', function ($scope) {
  $scope.bar = 'foo';
});
app.controller('foo2', function ($scope) {
  // want to access the $scope of foo1 here, to access bar
});
app.controller('foo1', f