=====給了我思路。

【新增第三方jar的類 作Service層的依賴失敗 因為此錯。xml定義“同名bean”解決】

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1. Overview

In this article, we are discussing the Springorg.springframework.beans.factory.NoSuchBeanDefinitionException – this is a common exception thrown by the BeanFactory when trying to resolve a bean that simply isn’t defined in the Spring Context.

We will discuss here the possible causes for this problem and the available solutions.

2. Cause: No qualifying bean of type [...] found for dependency

The most common cause of this exception is simply trying to inject a bean that isn’t defined. For example – BeanB is wiring in a collaborator – BeanA: 

Now, if the dependency – BeanB – is not defined in the Spring Context, the bootstrap process will fail with the no such bean definition exception:

The reason is clearly indicated by Spring: “expected at least 1 bean which qualifies as autowire candidate for this dependency“

One reason BeanB may not exist in the context – if beans are picked up automatically byclasspath scanning, and if BeanB is correctly annotated as a bean (@Component,@Repository, @Service, @Controller, etc) – is that it may be defined in a package that is not scanned by Spring:

While the classpath scanning may be configured as follows:

If beans are not automatically scanned by instead defined manually, then BeanB is simply not defined in the current Spring Context.

3. Cause: No qualifying bean of type [...] is defined

Another cause for the exception is the existence of two bean definitions in the context, instead of one. For example, if an interface – IBeanB is implemented by two beans –BeanB1 and BeanB2:

Now, if BeanA autowires this interface, Spring will not know which one of the two implementations to inject:

And again, this will result in a NoSuchBeanDefinitionException being thrown by theBeanFactory:

Similarly, Spring clearly indicates the reason for the wiring failure: “expected single matching bean but found 2″.

Notice however, that in this case, the exact exception being thrown is notNoSuchBeanDefinitionException but a subclass – theNoUniqueBeanDefinitionException. This new exception has been introduced in Spring 3.2.1, for exactly this reason – to differentiate between the cause where no bean definition was found and this one – where several definitions are found in the context.

Before this change, the exception above was: