Spring的ApplicationContext继承了ResourceLoader接口.这个接口主要就是可以加载各种resource..
接口还是比较简单的:
1 /* 2 * Copyright 2002-2014 the original author or authors. 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package org.springframework.core.io; 18 19 import org.springframework.util.ResourceUtils; 20 21 /** 22 * Strategy interface for loading resources (e.. class path or file system 23 * resources). An {@link org.springframework.context.ApplicationContext} 24 * is required to provide this functionality, plus extended 25 * {@link org.springframework.core.io.support.ResourcePatternResolver} support. 26 * 27 * <p>{@link DefaultResourceLoader} is a standalone implementation that is 28 * usable outside an ApplicationContext, also used by {@link ResourceEditor}. 29 * 30 * <p>Bean properties of type Resource and Resource array can be populated 31 * from Strings when running in an ApplicationContext, using the particular 32 * context's resource loading strategy. 33 * 34 * @author Juergen Hoeller 35 * @since 10.03.2004 36 * @see Resource 37 * @see org.springframework.core.io.support.ResourcePatternResolver 38 * @see org.springframework.context.ApplicationContext 39 * @see org.springframework.context.ResourceLoaderAware 40 */ 41 public interface ResourceLoader { 42 43 /** Pseudo URL prefix for loading from the class path: "classpath:" */ 44 String CLASSPATH_URL_PREFIX = ResourceUtils.CLASSPATH_URL_PREFIX; 45 46 47 /** 48 * Return a Resource handle for the specified resource. 49 * The handle should always be a reusable resource descriptor, 50 * allowing for multiple {@link Resource#getInputStream()} calls. 51 * <p><ul> 52 * <li>Must support fully qualified URLs, e.g. "file:C:/test.dat". 53 * <li>Must support classpath pseudo-URLs, e.g. "classpath:test.dat". 54 * <li>Should support relative file paths, e.g. "WEB-INF/test.dat". 55 * (This will be implementation-specific, typically provided by an 56 * ApplicationContext implementation.) 57 * </ul> 58 * <p>Note that a Resource handle does not imply an existing resource; 59 * you need to invoke {@link Resource#exists} to check for existence. 60 * @param location the resource location 61 * @return a corresponding Resource handle 62 * @see #CLASSPATH_URL_PREFIX 63 * @see org.springframework.core.io.Resource#exists 64 * @see org.springframework.core.io.Resource#getInputStream 65 */ 66 Resource getResource(String location); 67 68 /** 69 * Expose the ClassLoader used by this ResourceLoader. 70 * <p>Clients which need to access the ClassLoader directly can do so 71 * in a uniform manner with the ResourceLoader, rather than relying 72 * on the thread context ClassLoader. 73 * @return the ClassLoader (only {@code null} if even the system 74 * ClassLoader isn't accessible) 75 * @see org.springframework.util.ClassUtils#getDefaultClassLoader() 76 */ 77 ClassLoader getClassLoader(); 78 79 }