Java/File Input Output/Resources
Содержание
Load a resource as a stream
<source lang="java">
import java.io.IOException; import java.io.InputStream; import java.net.URL; import java.util.ArrayList; import java.util.Enumeration; import java.util.List;
//Revised from apache cxf public class Main {
/** * Load a given resource. <p/> This method will try to load the resource * using the following methods (in order):*
-
*
- From Thread.currentThread().getContextClassLoader() *
- From ClassLoaderUtil.class.getClassLoader() *
- callingClass.getClassLoader() *
*
* @param resourceName The name of the resource to load
* @param callingClass The Class object of the calling object
*/
public static URL getResource(String resourceName, Class callingClass) {
URL url = Thread.currentThread().getContextClassLoader().getResource(resourceName);
if (url == null && resourceName.startsWith("/")) {
//certain classloaders need it without the leading /
url = Thread.currentThread().getContextClassLoader()
.getResource(resourceName.substring(1));
}
ClassLoader cluClassloader = Main.class.getClassLoader();
if (cluClassloader == null) {
cluClassloader = ClassLoader.getSystemClassLoader();
}
if (url == null) {
url = cluClassloader.getResource(resourceName);
}
if (url == null && resourceName.startsWith("/")) {
//certain classloaders need it without the leading /
url = cluClassloader.getResource(resourceName.substring(1));
}
if (url == null) {
ClassLoader cl = callingClass.getClassLoader();
if (cl != null) {
url = cl.getResource(resourceName);
}
}
if (url == null) {
url = callingClass.getResource(resourceName);
}
if ((url == null) && (resourceName != null) && (resourceName.charAt(0) != "/")) {
return getResource("/" + resourceName, callingClass);
}
return url;
}
/**
* This is a convenience method to load a resource as a stream. <p/> The
* algorithm used to find the resource is given in getResource()
*
* @param resourceName The name of the resource to load
* @param callingClass The Class object of the calling object
*/
public static InputStream getResourceAsStream(String resourceName, Class callingClass) {
URL url = getResource(resourceName, callingClass);
try {
return (url != null) ? url.openStream() : null;
} catch (IOException e) {
return null;
}
}
/**
* Load a given resources. <p/> This method will try to load the resources
* using the following methods (in order):
* -
*
- From Thread.currentThread().getContextClassLoader() *
- From ClassLoaderUtil.class.getClassLoader() *
- callingClass.getClassLoader() *
*
* @param resourceName The name of the resource to load
* @param callingClass The Class object of the calling object
*/
public static List<URL> getResources(String resourceName, Class callingClass) {
List<URL> ret = new ArrayList<URL>();
Enumeration<URL> urls = new Enumeration<URL>() {
public boolean hasMoreElements() {
return false;
}
public URL nextElement() {
return null;
}
};
try {
urls = Thread.currentThread().getContextClassLoader()
.getResources(resourceName);
} catch (IOException e) {
//ignore
}
if (!urls.hasMoreElements() && resourceName.startsWith("/")) {
//certain classloaders need it without the leading /
try {
urls = Thread.currentThread().getContextClassLoader()
.getResources(resourceName.substring(1));
} catch (IOException e) {
// ignore
}
}
ClassLoader cluClassloader = Main.class.getClassLoader();
if (cluClassloader == null) {
cluClassloader = ClassLoader.getSystemClassLoader();
}
if (!urls.hasMoreElements()) {
try {
urls = cluClassloader.getResources(resourceName);
} catch (IOException e) {
// ignore
}
}
if (!urls.hasMoreElements() && resourceName.startsWith("/")) {
//certain classloaders need it without the leading /
try {
urls = cluClassloader.getResources(resourceName.substring(1));
} catch (IOException e) {
// ignore
}
}
if (!urls.hasMoreElements()) {
ClassLoader cl = callingClass.getClassLoader();
if (cl != null) {
try {
urls = cl.getResources(resourceName);
} catch (IOException e) {
// ignore
}
}
}
if (!urls.hasMoreElements()) {
URL url = callingClass.getResource(resourceName);
if (url != null) {
ret.add(url);
}
}
while (urls.hasMoreElements()) {
ret.add(urls.nextElement());
}
if (ret.isEmpty() && (resourceName != null) && (resourceName.charAt(0) != "/")) {
return getResources("/" + resourceName, callingClass);
}
return ret;
}
}
</source>
Loading resources and classes in a fault tolerant manner
<source lang="java">
/*
* Copyright (c) 2002-2003 by OpenSymphony * All rights reserved. */
import java.io.IOException; import java.io.InputStream; import java.net.URL; import java.util.Collections;
/**
* This class is extremely useful for loading resources and classes in a fault tolerant manner * that works across different applications servers. * <p/> * It has come out of many months of frustrating use of multiple application servers at Atlassian, * please don"t change things unless you"re sure they"re not going to break in one server or another! * * @author plightbo * @author tmjee * @version $Date: 2007-11-30 18:45:26 +0800 (Fri, 30 Nov 2007) $ $Id: ClassLoaderUtils.java 2977 2007-11-30 10:45:26Z tm_jee $ */
public class ClassLoaderUtils {
/**
* Load a given resource.
* <p/>
* This method will try to load the resource using the following methods (in order):
* -
*
- From {@link Thread#getContextClassLoader() Thread.currentThread().getContextClassLoader()} *
- From {@link Class#getClassLoader() ClassLoaderUtil.class.getClassLoader()} *
- From the {@link Class#getClassLoader() callingClass.getClassLoader() } *
*
* @param resourceName The name of the resource to load
* @param callingClass The Class object of the calling object
*/
public static URL getResource(String resourceName, Class callingClass) {
URL url = null;
url = Thread.currentThread().getContextClassLoader().getResource(resourceName);
if (url == null) {
url = ClassLoaderUtils.class.getClassLoader().getResource(resourceName);
}
if (url == null) {
url = callingClass.getClassLoader().getResource(resourceName);
}
return url;
}
/**
* This is a convenience method to load a resource as a stream.
* <p/>
* The algorithm used to find the resource is given in getResource()
*
* @param resourceName The name of the resource to load
* @param callingClass The Class object of the calling object
*/
public static InputStream getResourceAsStream(String resourceName, Class callingClass) {
URL url = getResource(resourceName, callingClass);
try {
return (url != null) ? url.openStream() : null;
} catch (IOException e) {
return null;
}
}
/**
* Load a class with a given name.
* <p/>
* It will try to load the class in the following order:
* -
*
- From {@link Thread#getContextClassLoader() Thread.currentThread().getContextClassLoader()} *
- Using the basic {@link Class#forName(java.lang.String) } *
- From {@link Class#getClassLoader() ClassLoaderUtil.class.getClassLoader()} *
- From the {@link Class#getClassLoader() callingClass.getClassLoader() } *
*
* @param className The name of the class to load
* @param callingClass The Class object of the calling object
* @throws ClassNotFoundException If the class cannot be found anywhere.
*/
public static Class loadClass(String className, Class callingClass) throws ClassNotFoundException {
try {
return Thread.currentThread().getContextClassLoader().loadClass(className);
} catch (ClassNotFoundException e) {
try {
return Class.forName(className);
} catch (ClassNotFoundException ex) {
try {
return ClassLoaderUtils.class.getClassLoader().loadClass(className);
} catch (ClassNotFoundException exc) {
return callingClass.getClassLoader().loadClass(className);
}
}
}
}
/**
* Prints the current classloader hierarchy - useful for debugging.
*/
public static void printClassLoader() {
System.out.println("ClassLoaderUtils.printClassLoader");
printClassLoader(Thread.currentThread().getContextClassLoader());
}
/**
* Prints the classloader hierarchy from a given classloader - useful for debugging.
*/
public static void printClassLoader(ClassLoader cl) {
System.out.println("ClassLoaderUtils.printClassLoader(cl = " + cl + ")");
if (cl != null) {
printClassLoader(cl.getParent());
}
}
}
</source>
Return a resource URL.
<source lang="java">
/*
* Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You 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.net.MalformedURLException; import java.net.URL; /**
* A collection of class management utility methods. * * @version $Id: ClassUtils.java 587751 2007-10-24 02:41:36Z vgritsenko $ */
public class ClassUtils {
/**
* Return a resource URL.
* BL: if this is command line operation, the classloading issues
* are more sane. During servlet execution, we explicitly set
* the ClassLoader.
*
* @return The context classloader.
* @exception MalformedURLException If a loading error occurs
*/
public static URL getResource(String resource) throws MalformedURLException {
return getClassLoader().getResource(resource);
}
/**
* Return the context classloader.
* BL: if this is command line operation, the classloading issues
* are more sane. During servlet execution, we explicitly set
* the ClassLoader.
*
* @return The context classloader.
*/
public static ClassLoader getClassLoader() {
return Thread.currentThread().getContextClassLoader();
}
}
</source>
Utility class to manage localization resources
<source lang="java">
/*****************************************************************************
* Java Plug-in Framework (JPF) * Copyright (C) 2004-2005 Dmitry Olshansky * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA *****************************************************************************/
import java.util.Collection; import java.util.Collections; import java.util.HashMap; import java.util.Locale; import java.util.Map; import java.util.MissingResourceException; import java.util.ResourceBundle; /**
* Utility class to manage localization resources. This class is not for public * usage but mainly for custom implementations developers to provide them * uniform access and organization of locale specific data. *
* Class usage is very simple. Put your locale sensible data into *Resources.propertiesfiles and save them near classes that you * are going to get localized. For {@link java.util.Locale} to file mapping * details see {@link ResourceBundle} documentation. * * @version $Id$ */
public final class ResourceManager {
private static final Object FAKE_BUNDLE = new Object();
private static final Map<String, Object> bundles =
Collections.synchronizedMap(new HashMap<String, Object>());
/**
* @param packageName package name, used for
* Resources.properties file look-up
* @param messageKey message key
* @return message for {@link Locale#getDefault() default locale}
*/
public static String getMessage(final String packageName,
final String messageKey) {
return getMessage(packageName, messageKey, Locale.getDefault(), null);
}
/**
* @param packageName package name, used for
* Resources.properties file look-up
* @param messageKey message key
* @param data data for parameter placeholders substitution, may be
* Object, array or
* Collection.
* @return message for {@link Locale#getDefault() default locale}
*/
public static String getMessage(final String packageName,
final String messageKey, final Object data) {
return getMessage(packageName, messageKey, Locale.getDefault(), data);
}
/**
* @param packageName package name, used for
* Resources.properties file look-up
* @param messageKey message key
* @param locale locale to get message for
* @return message for given locale
*/
public static String getMessage(final String packageName,
final String messageKey, final Locale locale) {
return getMessage(packageName, messageKey, locale, null);
}
/**
* @param packageName package name, used for
* Resources.properties file look-up
* @param messageKey message key
* @param locale locale to get message for
* @param data data for parameter placeholders substitution, may be
* Object, array or
* Collection.
* @return message for given locale
*/
public static String getMessage(final String packageName,
final String messageKey, final Locale locale, final Object data) {
Object obj = bundles.get(packageName + "|" + locale);
if (obj == null) {
try {
obj = ResourceBundle.getBundle(packageName + ".Resources", //$NON-NLS-1$
locale);
} catch (MissingResourceException mre) {
obj = FAKE_BUNDLE;
}
bundles.put(packageName + "|" + locale, obj);
}
if (obj == FAKE_BUNDLE) {
return "resource " + packageName + "." + messageKey //$NON-NLS-1$
+ " not found for locale " + locale; //$NON-NLS-1$
}
try {
String result = ((ResourceBundle) obj).getString(messageKey);
return (data == null) ? result : processParams(result, data);
} catch (MissingResourceException mre) {
return "resource " + packageName + "." + messageKey //$NON-NLS-1$
+ " not found for locale " + locale; //$NON-NLS-1$
}
}
private static String processParams(final String str, final Object data) {
String result = str;
if ((data != null) && data.getClass().isArray()) {
Object[] params = (Object[])data;
for (int i = 0; i < params.length; i++) {
result = replaceAll(result, "{" + i + "}", "" + params[i]); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
}
} else if (data instanceof Collection) {
int i = 0;
for (Object object : (Collection) data) {
result = replaceAll(result, "{" + i++ + "}", "" + object); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
}
} else {
result = replaceAll(result, "{0}", "" + data); //$NON-NLS-1$ //$NON-NLS-2$
}
return result;
}
private static String replaceAll(final String str, final String from,
final String to) {
String result = str;
int p = 0;
while (true) {
p = result.indexOf(from, p);
if (p == -1) {
break;
}
result = result.substring(0, p) + to
+ result.substring(p + from.length());
p += to.length();
}
return result;
}
private ResourceManager() {
// no-op
}
}
</source>
Utility methods for resolving resource locations to files in the file system
<source lang="java">
/*
* Copyright 2002-2007 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.File; import java.io.FileNotFoundException; import java.net.MalformedURLException; import java.net.URL; import java.net.URLDecoder; /**
* Utility methods for resolving resource locations to files in the * file system. Mainly for internal use within the framework. **
Consider using Spring"s Resource abstraction in the core package
* for handling all kinds of file resources in a uniform manner.
* {@link org.springframework.core.io.ResourceLoader}"s getResource
* method can resolve any location to a {@link org.springframework.core.io.Resource}
* object, which in turn allows to obtain a java.io.File in the
* file system through its getFile() method.
*
* <p>The main reason for these utility methods for resource location handling
* is to support {@link Log4jConfigurer}, which must be able to resolve
* resource locations before the logging system has been initialized.
* Spring" Resource abstraction in the core package, on the other hand,
* already expects the logging system to be available.
*
* @author Juergen Hoeller
* @since 1.1.5
* @see org.springframework.core.io.Resource
* @see org.springframework.core.io.ClassPathResource
* @see org.springframework.core.io.FileSystemResource
* @see org.springframework.core.io.UrlResource
* @see org.springframework.core.io.ResourceLoader
*/
public abstract class ResourceUtils {
/** Pseudo URL prefix for loading from the class path: "classpath:" */
public static final String CLASSPATH_URL_PREFIX = "classpath:";
/** URL prefix for loading from the file system: "file:" */
public static final String FILE_URL_PREFIX = "file:";
/** URL protocol for a file in the file system: "file" */
public static final String URL_PROTOCOL_FILE = "file";
/** URL protocol for an entry from a jar file: "jar" */
public static final String URL_PROTOCOL_JAR = "jar";
/** URL protocol for an entry from a zip file: "zip" */
public static final String URL_PROTOCOL_ZIP = "zip";
/** URL protocol for an entry from a WebSphere jar file: "wsjar" */
public static final String URL_PROTOCOL_WSJAR = "wsjar";
/** URL protocol for an entry from an OC4J jar file: "code-source" */
public static final String URL_PROTOCOL_CODE_SOURCE = "code-source";
/** Separator between JAR URL and file path within the JAR */
public static final String JAR_URL_SEPARATOR = "!/";
/**
* Return whether the given resource location is a URL:
* either a special "classpath" pseudo URL or a standard URL.
* @param resourceLocation the location String to check
* @return whether the location qualifies as a URL
* @see #CLASSPATH_URL_PREFIX
* @see java.net.URL
*/
public static boolean isUrl(String resourceLocation) {
if (resourceLocation == null) {
return false;
}
if (resourceLocation.startsWith(CLASSPATH_URL_PREFIX)) {
return true;
}
try {
new URL(resourceLocation);
return true;
}
catch (MalformedURLException ex) {
return false;
}
}
/**
* Determine whether the given URL points to a resource in a jar file,
* that is, has protocol "jar", "zip", "wsjar" or "code-source".
* <p>"zip" and "wsjar" are used by BEA WebLogic Server and IBM WebSphere, respectively,
* but can be treated like jar files. The same applies to "code-source" URLs on Oracle
* OC4J, provided that the path contains a jar separator.
* @param url the URL to check
* @return whether the URL has been identified as a JAR URL
*/
public static boolean isJarURL(URL url) {
String protocol = url.getProtocol();
return (URL_PROTOCOL_JAR.equals(protocol) ||
URL_PROTOCOL_ZIP.equals(protocol) ||
URL_PROTOCOL_WSJAR.equals(protocol) ||
(URL_PROTOCOL_CODE_SOURCE.equals(protocol) && url.getPath().indexOf(JAR_URL_SEPARATOR) != -1));
}
/**
* Extract the URL for the actual jar file from the given URL
* (which may point to a resource in a jar file or to a jar file itself).
* @param jarUrl the original URL
* @return the URL for the actual jar file
* @throws MalformedURLException if no valid jar file URL could be extracted
*/
public static URL extractJarFileURL(URL jarUrl) throws MalformedURLException {
String urlFile = jarUrl.getFile();
int separatorIndex = urlFile.indexOf(JAR_URL_SEPARATOR);
if (separatorIndex != -1) {
String jarFile = urlFile.substring(0, separatorIndex);
try {
return new URL(jarFile);
}
catch (MalformedURLException ex) {
// Probably no protocol in original jar URL, like "jar:C:/mypath/myjar.jar".
// This usually indicates that the jar file resides in the file system.
if (!jarFile.startsWith("/")) {
jarFile = "/" + jarFile;
}
return new URL(FILE_URL_PREFIX + jarFile);
}
}
else {
return jarUrl;
}
}
}
</source>
