Spring：为类路径资源注入URL

Question

I want to inject the URL of a classpath resource in a way that does not create a dependency on Spring in the Bean. Meaning, the bean should not use Spring's interfaces/classes. How can I do that?

Answer 1

Spring is able to convert classpath:... values into java.net.URL implicitly:

public class Foo {
    private URL url;
    ...
}

.

<bean class = "Foo">
    <property name = "url" value = "classpath:..." />
</bean>

Answer 2

从axtavt的回答开始，如果你允许自己在bean中使用Spring注释，你可以这样做：

@Value("classpath:myClasspathLocation") private URL url;

Answer 3

create your own implementation of a spring resource by extending the org.springframework.core.io.ClassPathResource like MyClasspathResource extends ClassPathResource and inject this type into your bean. Like this you do not have any dependency to spring and can later reimplement your resource with something else.

<bean class="myBean">
 <property name="classPathType">
  <bean class="org.test.bla.MyClasspathResource">
   <constructor-arg index="0" value="classpath:/org/test/bla/MyUrl" />
  </bean>
 </property>
</bean>

Answer 4

There is hardly anything non-spring that's equivalent to Spring's resource concept .

You could for example use Guava 's InputSupplier as an alternative, but you are missing powerful standard spring features if you do.