In essence, bijection lets you alias a context variable to a component instance variable, by specifying that the value of the instance variable is injected, outjected, or both.

• 本质上说，双向注射能够让你通过指定实例变量的值是注入，还是注出或者两者都是，从而将一个上下文变量别名为一个组件的实例变量。