在我实例化的自定义类中获取angular 2服务

风俗 现在,我需要在该类中使用angular 2实例化的一些服务。

即

// this is not angular component/service
export default class Custom {

    constructor(properties) {

    }
    doSomething() {
        // UserService is a service that is injected into other componetns constructors, but this class is not a component.
        // Here i need a ref to the singleton 'UserService' made by angular
        let userService = someAngularFunction.getInstance('UserService');
        userService.doIt();
    }

}

// in some component.
export class MyComponent implements OnInit {
    doAnotherThing() {
       let c = new Custom('some generic params');
       c.doSomething();
    }
}
// in some n number of other components, repeat the above.

'进入 MyComponent公司 MyComponent公司 ,传递给 构造函数。但是,由于MyComponent本身不使用该服务

风俗

如果不是,第二个最好的选择是什么。