日期:2014-05-19  浏览次数:20754 次

请教:Spring @Autowired注解实现了接口的成员变量时失败
场景:
1、类A中有成员变量类B,类B使用@Autowired注解的方式注入A中。
2、类B实现了接口IB.

问题:
启动时报错:
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'a': 
Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException:
Could not autowire field: com.siqisoft.test.B com.siqisoft.test.A.b; 
nested exception is java.lang.IllegalArgumentException: 
Can not set com.siqisoft.test.B field com.siqisoft.test.A.b to $Proxy23

疑问:
为什么实现了接口的B不能被注入到A中呢?

类A:
Java code

package com.siqisoft.test;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

@Component
public class A {
    @Autowired
    B b;
}



类B:
Java code

package com.siqisoft.test;

import org.springframework.stereotype.Component;

@Component
public class B {
     public  void  BMethod(){};
}


B实现的接口
Java code

package com.siqisoft.test;

public abstract interface IB   {
    
}




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探讨

整个错误堆栈
Java code

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'a': Injection of autowired dependencies failed; nested exception is org.springframework.bea……

------解决方案--------------------
Error creating bean with name 'a':

又那里来的a列?

关于你的思考,回答如下:

 @Autowired
@Qualifier("b") //用B类型去注入. 请注意类名首字母小写
private BI b