关于Spring xml中如何配置A类注入B类，同时B类注入到A类的探讨

# package cn.javass.spring.chapter3.bean; 
# public class CircleA { 
#     private CircleB circleB; 
#     public CircleA() { 
#     } 
#     public CircleA(CircleB circleB) { 
#         this.circleB = circleB; 
#     } 
# public void setCircleB(CircleB circleB)  
# { 
#         this.circleB = circleB; 
#     } 
# public void a() { 
#    circleB.b(); 
# } 
# }


# package cn.javass.spring.chapter3.bean; 
# public class CircleB { 
#     private CircleA circleA; 
#     public CircleB() { 
#     } 
#     public CircleB(CircleA circleA) { 
#         this.circleA = circleA; 
#     } 
# public void setCircleA(CircleA circleA)  
# { 
#         this.circleA = circleA; 
#     } 
#     public void b() { 
#         circleA.a(); 
#     } 
# }

配置如下：
# <bean id="circleA" class="cn.javass.spring.chapter3.bean.CircleA" scope="singleton"> 
#         <property name="circleB" ref="circleB"/> 
#    </bean> 
#    <bean id="circleB" class="cn.javass.spring.chapter3.bean.CircleB" scope="singleton"> 
#        <property name="circleA" ref="circleA"/> 
#    </bean> 

这样配应该不会抛beancurrentlyincreationexception