java - 为什么 Spring 将工厂方法 arg 报告为不明确？

Question

我正在尝试创建这个 bean:

<bean id="myBean" class="java.lang.String" factory-method="valueOf">
    <constructor-arg name="obj" value="a string" type="java.lang.Object"/>
</bean>

我希望 Spring 在创建 bean 时使用此方法 java.lang.String#valueOf(Object obj)。

我得到:

Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'myBean' defined in class path resource [META-INF/test-contexts/testManualDependencyBundleResolverContext.xml]: Unsatisfied dependency expressed through constructor argument with index 0 of type [char[]]: Ambiguous factory method argument types - did you specify the correct bean references as factory method arguments?
Related cause: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'myBean' defined in class path resource [META-INF/test-contexts/testManualDependencyBundleResolverContext.xml]: Unsatisfied dependency expressed through constructor argument with index 0 of type [char[]]: Ambiguous factory method argument types - did you specify the correct bean references as factory method arguments?
Related cause: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'myBean' defined in class path resource [META-INF/test-contexts/testManualDependencyBundleResolverContext.xml]: Unsatisfied dependency expressed through constructor argument with index 0 of type [boolean]: Ambiguous factory method argument types - did you specify the correct bean references as factory method arguments?
Related cause: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'myBean' defined in class path resource [META-INF/test-contexts/testManualDependencyBundleResolverContext.xml]: Unsatisfied dependency expressed through constructor argument with index 0 of type [long]: Ambiguous factory method argument types - did you specify the correct bean references as factory method arguments?
Related cause: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'myBean' defined in class path resource [META-INF/test-contexts/testManualDependencyBundleResolverContext.xml]: Unsatisfied dependency expressed through constructor argument with index 0 of type [char]: Ambiguous factory method argument types - did you specify the correct bean references as factory method arguments?
Related cause: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'myBean' defined in class path resource [META-INF/test-contexts/testManualDependencyBundleResolverContext.xml]: Unsatisfied dependency expressed through constructor argument with index 0 of type [double]: Ambiguous factory method argument types - did you specify the correct bean references as factory method arguments?
Related cause: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'myBean' defined in class path resource [META-INF/test-contexts/testManualDependencyBundleResolverContext.xml]: Unsatisfied dependency expressed through constructor argument with index 0 of type [float]: Ambiguous factory method argument types - did you specify the correct bean references as factory method arguments?
Related cause: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'myBean' defined in class path resource [META-INF/test-contexts/testManualDependencyBundleResolverContext.xml]: Unsatisfied dependency expressed through constructor argument with index 0 of type [int]: Ambiguous factory method argument types - did you specify the correct bean references as factory method arguments?
Related cause: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'myBean' defined in class path resource [META-INF/test-contexts/testManualDependencyBundleResolverContext.xml]: Unsatisfied dependency expressed through constructor argument with index 0 of type [java.lang.Object]: Ambiguous factory method argument types - did you specify the correct bean references as factory method arguments?

为什么？我想我已经指定了 Spring 解析我希望它使用的正确方法所需的一切。

Answer 1

只需删除 name 属性，名称的 XSD 文档说:

Only needed to avoid ambiguities, e.g. in case of 2 arguments of 
 the exact same type. Note: This requires debug symbols to be 
 stored in the class file in order to introspect argument names!