解決，spring Is there an unresolvable circular reference?

當我們在使用spring的構造注入時可能會遇到如下問題：
Caused by: org.springframework.beans.factory.BeanCurrentlyInCreationException: Error creating bean with 
name 'linkInstanceService': Requested bean is currently in creation: Is there an unresolvable circular reference?
原因是在構造注入時，一旦服務器開啓就會加載，如果我們使用裝配模式就可以解決這個問題。