Interface ResourceLoader

All Known Subinterfaces:

ApplicationContext, ConfigurableApplicationContext, ConfigurableWebApplicationContext, ResourcePatternResolver, WebApplicationContext

All Known Implementing Classes:

AbstractApplicationContext, AbstractRefreshableApplicationContext, AbstractRefreshableConfigApplicationContext, AbstractRefreshableWebApplicationContext, AbstractXmlApplicationContext, AnnotationConfigApplicationContext, AnnotationConfigWebApplicationContext, ClassPathXmlApplicationContext, ClassRelativeResourceLoader, DefaultResourceLoader, FileSystemResourceLoader, FileSystemXmlApplicationContext, GenericApplicationContext, GenericGroovyApplicationContext, GenericWebApplicationContext, GenericXmlApplicationContext, GroovyWebApplicationContext, PathMatchingResourcePatternResolver, ServletContextResourceLoader, ServletContextResourcePatternResolver, StaticApplicationContext, StaticWebApplicationContext, XmlWebApplicationContext

public interface ResourceLoader

Strategy interface for loading resources (for example, class path or file system resources). An ApplicationContext is required to provide this functionality plus extended ResourcePatternResolver support.

DefaultResourceLoader is a standalone implementation that is usable outside an ApplicationContext and is also used by ResourceEditor.

Bean properties of type Resource and Resource[] can be populated from Strings when running in an ApplicationContext, using the particular context's resource loading strategy.

Since:

10.03.2004

Author:

Juergen Hoeller

See Also:

• Resource
• ResourcePatternResolver
• ApplicationContext
• ResourceLoaderAware

Field Summary

Fields

Modifier and Type	Field	Description
static final String	CLASSPATH_ALL_URL_PREFIX	Pseudo URL prefix for all matching resources from the class path: "classpath*:".
static final String	CLASSPATH_URL_PREFIX	Pseudo URL prefix for loading from the class path: "classpath:".

Method Summary

Modifier and Type	Method	Description
@Nullable ClassLoader	getClassLoader()	Expose the ClassLoader used by this ResourceLoader.
Resource	getResource(String location)	Return a Resource handle for the specified resource location.

Field Details

CLASSPATH_URL_PREFIX

static final String CLASSPATH_URL_PREFIX

Pseudo URL prefix for loading from the class path: "classpath:".

This retrieves the "nearest" matching resource in the classpath.

See Also:

• ClassLoader.getResource(String)
• Constant Field Values

CLASSPATH_ALL_URL_PREFIX

static final String CLASSPATH_ALL_URL_PREFIX

Pseudo URL prefix for all matching resources from the class path: "classpath*:".

This differs from the common "classpath:" prefix in that it retrieves all matching resources for a given path. For example, to locate all "messages.properties" files in the root of all deployed JAR files you can use the location pattern "classpath*:/messages.properties".

As of Spring Framework 6.0, the semantics for the "classpath*:" prefix have been expanded to include the module path as well as the class path.

As of Spring Framework 7.1, this prefix is supported for getResource(String) calls as well (exposing a multi-content resource handle), rather than just for ResourcePatternResolver.getResources(String).

Since:

7.1 (previously only declared on the ResourcePatternResolver sub-interface)

See Also:

• ClassLoader.getResources(String)
• Resource.consumeContent(IOConsumer)
• Constant Field Values

Method Details

getResource

Resource getResource(String location)

Return a Resource handle for the specified resource location.

The handle should always be a reusable resource descriptor, allowing for multiple InputStreamSource.getInputStream() calls.

• Must support fully qualified URLs, for example, "file:C:/test.properties".
• Must support classpath pseudo-URLs, for example, "classpath:test.properties". (Exposing the "nearest" resource in the classpath; see ClassLoader.getResource(String).)
• Should support classpath-all URLs, for example, "classpath*:test.properties". (If supported, the returned Resource needs to expose the entire content of all same-named resources in the classpath through Resource.consumeContent(IOConsumer); see ClassLoader.getResources(String). For individual access to each such matching resource in the classpath, use ResourcePatternResolver.getResources(String).)
• Should support relative file paths, for example, "WEB-INF/test.properties". (This will be implementation-specific, typically provided by an ApplicationContext implementation.)

Note that a Resource handle does not imply an existing resource; you need to invoke Resource.exists() to check for existence.

Parameters:

location - the resource location

Returns:

a corresponding Resource handle (never null)

See Also:

• CLASSPATH_URL_PREFIX
• CLASSPATH_ALL_URL_PREFIX
• Resource.exists()
• Resource.consumeContent(IOConsumer)

getClassLoader

@Nullable ClassLoader getClassLoader()

Expose the ClassLoader used by this ResourceLoader.

Clients which need to access the ClassLoader directly can do so in a uniform manner with the ResourceLoader, rather than relying on the thread context ClassLoader.

Returns:

the ClassLoader (only null if even the system ClassLoader isn't accessible)

See Also:

• ClassUtils.getDefaultClassLoader()
• ClassUtils.forName(String, ClassLoader)