Java tutorial
package com.sfxie.extension.spring4.properties; /* * Copyright 2002-2014 the original author or authors. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ import java.io.IOException; import java.io.InputStream; import java.io.Reader; import java.net.URL; import java.net.URLConnection; import java.util.Enumeration; import java.util.Properties; import org.springframework.core.io.Resource; import org.springframework.core.io.support.EncodedResource; import org.springframework.util.Assert; import org.springframework.util.ClassUtils; import org.springframework.util.DefaultPropertiesPersister; import org.springframework.util.PropertiesPersister; import org.springframework.util.ResourceUtils; /** * Convenient utility methods for loading of {@code java.util.Properties}, * performing standard handling of input streams. * * <p>For more configurable properties loading, including the option of a * customized encoding, consider using the PropertiesLoaderSupport class. * * @author Juergen Hoeller * @author Rob Harrop * @since 2.0 * @see PropertiesLoaderSupport */ public abstract class PropertiesLoaderUtils { private static final String XML_FILE_EXTENSION = ".xml"; /** * Load properties from the given EncodedResource, * potentially defining a specific encoding for the properties file. * @see #fillProperties(java.util.Properties, EncodedResource) */ public static Properties loadProperties(EncodedResource resource) throws IOException { Properties props = new Properties(); fillProperties(props, resource); return props; } /** * Fill the given properties from the given EncodedResource, * potentially defining a specific encoding for the properties file. * @param props the Properties instance to load into * @param resource the resource to load from * @throws IOException in case of I/O errors */ public static void fillProperties(Properties props, EncodedResource resource) throws IOException { fillProperties(props, resource, new DefaultPropertiesPersister()); } /** * Actually load properties from the given EncodedResource into the given Properties instance. * @param props the Properties instance to load into * @param resource the resource to load from * @param persister the PropertiesPersister to use * @throws IOException in case of I/O errors */ static void fillProperties(Properties props, EncodedResource resource, PropertiesPersister persister) throws IOException { InputStream stream = null; Reader reader = null; try { String filename = resource.getResource().getFilename(); if (filename != null && filename.endsWith(XML_FILE_EXTENSION)) { stream = resource.getInputStream(); persister.loadFromXml(props, stream); } else if (resource.requiresReader()) { reader = resource.getReader(); persister.load(props, reader); } else { stream = resource.getInputStream(); persister.load(props, stream); } } finally { if (stream != null) { stream.close(); } if (reader != null) { reader.close(); } } } /** * Load properties from the given resource (in ISO-8859-1 encoding). * @param resource the resource to load from * @return the populated Properties instance * @throws IOException if loading failed * @see #fillProperties(java.util.Properties, Resource) */ public static Properties loadProperties(Resource resource) throws IOException { Properties props = new Properties(); fillProperties(props, resource); return props; } /** * Fill the given properties from the given resource (in ISO-8859-1 encoding). * @param props the Properties instance to fill * @param resource the resource to load from * @throws IOException if loading failed */ public static void fillProperties(Properties props, Resource resource) throws IOException { InputStream is = resource.getInputStream(); try { String filename = resource.getFilename(); if (filename != null && filename.endsWith(XML_FILE_EXTENSION)) { props.loadFromXML(is); } else { props.load(is); } } finally { is.close(); } } /** * Load all properties from the specified class path resource * (in ISO-8859-1 encoding), using the default class loader. * <p>Merges properties if more than one resource of the same name * found in the class path. * @param resourceName the name of the class path resource * @return the populated Properties instance * @throws IOException if loading failed */ public static Properties loadAllProperties(String resourceName) throws IOException { return loadAllProperties(resourceName, null); } /** * Load all properties from the specified class path resource * (in ISO-8859-1 encoding), using the given class loader. * <p>Merges properties if more than one resource of the same name * found in the class path. * @param resourceName the name of the class path resource * @param classLoader the ClassLoader to use for loading * (or {@code null} to use the default class loader) * @return the populated Properties instance * @throws IOException if loading failed */ public static Properties loadAllProperties(String resourceName, ClassLoader classLoader) throws IOException { Assert.notNull(resourceName, "Resource name must not be null"); ClassLoader classLoaderToUse = classLoader; if (classLoaderToUse == null) { classLoaderToUse = ClassUtils.getDefaultClassLoader(); } Enumeration<URL> urls = (classLoaderToUse != null ? classLoaderToUse.getResources(resourceName) : ClassLoader.getSystemResources(resourceName)); Properties props = new Properties(); while (urls.hasMoreElements()) { URL url = urls.nextElement(); URLConnection con = url.openConnection(); ResourceUtils.useCachesIfNecessary(con); InputStream is = con.getInputStream(); try { if (resourceName != null && resourceName.endsWith(XML_FILE_EXTENSION)) { props.loadFromXML(is); } else { props.load(is); } } finally { is.close(); } } return props; } }