`ResourceLoader`接口旨在由可返回（即加載）資源實例的對象實現。 ~~~java public interface ResourceLoader { Resource getResource(String location); } ~~~ 所有的應用上下文都實現了`ResourceLoader`接口,因此,所有應用上下文都可以獲取`Resource`的實例.當你在特定的應用上下文中調用`getResource()`時,且沒有指定前綴,會獲取一個符合應用的上下文`Resource `,如下,假設在`ClassPathXmlApplicationContext `上下文中調用 ~~~ Resource template = ctx.getResource("some/resource/path/myTemplate.txt"); ~~~ 返回的將是一個`ClassPathResource`.如果是在`FileSystemXmlApplicationContext `環境下調用方法,則返回的將是一個`FileSystemResource`.在`WebApplicationContext`環境下得到`ServletContextResource`. 也可以通過使用前綴`classpath:`,強制返回`ClassPathResource`: ~~~ Resource template = ctx.getResource("classpath:some/resource/path/myTemplate.txt"); ~~~ 下面的表格說明字符串轉為資源的策略: | Prefix | Example | Explanation | | --- | --- | --- | | classpath: | classpath:com/myapp/config.xml | Loaded from the classpath | | file: | file:///data/config.xml | Loaded as a URL, from the filesystem. | | http: | http://myserver/logo.png | Loaded as a URL. | | (none) | /data/config.xml | Depends on the underlying ApplicationContext. |