首页 > 代码库 > java常用工具方法2
java常用工具方法2
/* * Copyright 2005 Joe Walker * * 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. */package org.directwebremoting.util;import java.io.IOException;import java.io.InputStream;import java.io.RandomAccessFile;import java.io.Reader;import java.lang.reflect.Field;import java.lang.reflect.InvocationTargetException;import java.lang.reflect.Method;import java.net.URLDecoder;import java.util.ArrayList;import java.util.Arrays;import java.util.HashSet;import java.util.Iterator;import java.util.List;import java.util.Locale;import java.util.Map;import java.util.Set;import javax.servlet.ServletConfig;import javax.servlet.ServletContext;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.HttpSession;import javax.xml.transform.TransformerFactoryConfigurationError;/** * 一些通用的方法 * Various utilities, mostly to make up for JDK 1.4 functionallity that is not * in JDK 1.3 * @author Joe Walker [joe at getahead dot ltd dot uk] */public final class LocalUtil{ /** * splitInbound() returns the type info in this parameter */ public static final int INBOUND_INDEX_TYPE = 0; /** * splitInbound() returns the value info in this parameter */ public static final int INBOUND_INDEX_VALUE = http://www.mamicode.com/1; /** * Prevent instansiation */ private LocalUtil() { } /** * Replacement for String#replaceAll(String, String) in JDK 1.4+ * @param text source text * @param repl the stuff to get rid of * @param with the stuff to replace it with * @return replaced text or null if any args are null */ public static String replace(String text, String repl, String with) { if (text == null || repl == null || with == null || repl.length() == 0) { return text; } StringBuffer buf = new StringBuffer(text.length()); int searchFrom = 0; while (true) { int foundAt = text.indexOf(repl, searchFrom); if (foundAt == -1) { break; } buf.append(text.substring(searchFrom, foundAt)).append(with); searchFrom = foundAt + repl.length(); } buf.append(text.substring(searchFrom)); return buf.toString(); } /** * 判断给定的字符串是否符合 Java 标识符的规范 * * Determines if the specified string is permissible as a Java identifier. * Returns true if the string is non-null, non-zero length with a Java * identifier start as the first character and Java identifier parts in all * remaining characters. * @param test the string to be tested. * @return true if the string is a Java identifier, false otherwise. * @see java.lang.Character#isJavaIdentifierPart(char) * @see java.lang.Character#isJavaIdentifierStart(char) */ public static boolean isJavaIdentifier(String test) { if (test == null || test.length() == 0) { return false; } if (!Character.isJavaIdentifierStart(test.charAt(0)) && test.charAt(0) != ‘_‘) { return false; } for (int i = 1; i < test.length(); i++) { if (!Character.isJavaIdentifierPart(test.charAt(i)) && test.charAt(i) != ‘_‘) { return false; } } return true; } /** * Determines if the specified string contains only Unicode letters or * digits as defined by {@link Character#isLetterOrDigit(char)} * @param test The string to test * @return true if the string is non-null, non-empty and contains only * characters that are unicode letters or digits * @see Character#isLetterOrDigit(char) */ public static boolean isLetterOrDigitOrUnderline(String test) { if (test == null || test.length() == 0) { return false; } for (int i = 0; i < test.length(); i++) { if (!Character.isLetterOrDigit(test.charAt(i)) && test.charAt(i) != ‘_‘) { return false; } } return true; } /** * True if c1 is java.lang.Boolean and c2 is boolean, etc. * @param c1 the first class to test * @param c2 the second class to test * @return true if the classes are equivalent */ public static boolean isEquivalent(Class c1, Class c2) { if (c1 == Boolean.class || c1 == Boolean.TYPE) { return c2 == Boolean.class || c2 == Boolean.TYPE; } else if (c1 == Byte.class || c1 == Byte.TYPE) { return c2 == Byte.class || c2 == Byte.TYPE; } else if (c1 == Character.class || c1 == Character.TYPE) { return c2 == Character.class || c2 == Character.TYPE; } else if (c1 == Short.class || c1 == Short.TYPE) { return c2 == Short.class || c2 == Short.TYPE; } else if (c1 == Integer.class || c1 == Integer.TYPE) { return c2 == Integer.class || c2 == Integer.TYPE; } else if (c1 == Long.class || c1 == Long.TYPE) { return c2 == Long.class || c2 == Long.TYPE; } else if (c1 == Float.class || c1 == Float.TYPE) { return c2 == Float.class || c2 == Float.TYPE; } else if (c1 == Double.class || c1 == Double.TYPE) { return c2 == Double.class || c2 == Double.TYPE; } else if (c1 == Void.class || c1 == Void.TYPE) { return c2 == Void.class || c2 == Void.TYPE; } return false; } /** * @param type The class to de-primitivize * @return The non-privitive version of the class */ public static Class getNonPrimitiveType(Class type) { if (!type.isPrimitive()) { return type; } else if (type == Boolean.TYPE) { return Boolean.class; } else if (type == Byte.TYPE) { return Byte.class; } else if (type == Character.TYPE) { return Character.class; } else if (type == Short.TYPE) { return Short.class; } else if (type == Integer.TYPE) { return Integer.class; } else if (type == Long.TYPE) { return Long.class; } else if (type == Float.TYPE) { return Float.class; } else if (type == Double.TYPE) { return Double.class; } else if (type == Void.TYPE) { return Void.class; } return null; } /** * Add headers to prevent browers and proxies from caching this reply. * @param resp The response to add headers to */ public static void addNoCacheHeaders(HttpServletResponse resp) { // Set standard HTTP/1.1 no-cache headers. resp.setHeader("Cache-Control", "no-store, no-cache, must-revalidate"); // Set IE extended HTTP/1.1 no-cache headers (use addHeader). resp.addHeader("Cache-Control", "post-check=0, pre-check=0"); // Set standard HTTP/1.0 no-cache header. resp.setHeader("Pragma", "no-cache"); // Set to expire far in the past. Prevents caching at the proxy server resp.setHeader("Expires", "Sat, 6 May 1995 12:00:00 GMT"); } /** * Is this class one that we auto fill, so the user can ignore? * @param paramType The type to test * @return true if the type is a Servlet type */ public static boolean isServletClass(Class paramType) { return paramType == HttpServletRequest.class || paramType == HttpServletResponse.class || paramType == ServletConfig.class || paramType == ServletContext.class || paramType == HttpSession.class; } /** * URL decode a value. This method gets around the lack of a * decode(String, String) method in JDK 1.3. * @param value The string to decode * @return The decoded string */ public static String decode(String value) { if (!testedDecoder) { try { decode14 = URLDecoder.class.getMethod("decode", new Class[] { String.class, String.class }); } catch (Exception ex) { if (!warn13) { log.warn("URLDecoder.decode(String, String) is not available. Falling back to 1.3 variant."); warn13 = true; } } testedDecoder = true; } if (decode14 != null) { try { return (String) decode14.invoke(null, new Object[] { value, "UTF-8" }); } catch (Exception ex) { log.warn("Failed to use JDK 1.4 decoder", ex); } } return URLDecoder.decode(value); } /** * 用反射给对象设置属性集 * * Set use reflection to set the setters on the object called by the keys * in the params map with the corresponding values * @param object The object to setup * @param params The settings to use * @param ignore List of keys to not warn about if they are not properties * Note only the warning is skipped, we still try the setter */ public static void setParams(Object object, Map params, List ignore) { for (Iterator it = params.entrySet().iterator(); it.hasNext();) { Map.Entry entry = (Map.Entry) it.next(); String key = (String) entry.getKey(); Object value = entry.getValue(); try { setProperty(object, key, value); } catch (NoSuchMethodException ex) { if (ignore != null && !ignore.contains(key)) { log.warn("No property ‘" + key + "‘ on " + object.getClass().getName()); } } catch (InvocationTargetException ex) { log.warn("Error setting " + key + "=" + value + " on " + object.getClass().getName(), ex.getTargetException()); } catch (Exception ex) { log.warn("Error setting " + key + "=" + value + " on " + object.getClass().getName(), ex); } } } /** * 用反射给对象设置属性,通过给定的属性名。 * * Set a property on an object using reflection * @param object The object to call the setter on * @param key The name of the property to set. * @param value The new value to use for the property * @throws NoSuchMethodException Passed on from reflection code * @throws SecurityException Passed on from reflection code * @throws IllegalAccessException Passed on from reflection code * @throws IllegalArgumentException Passed on from reflection code * @throws InvocationTargetException Passed on from reflection code */ public static void setProperty(Object object, String key, Object value) throws NoSuchMethodException, SecurityException, IllegalAccessException, IllegalArgumentException, InvocationTargetException { Class real = object.getClass(); String setterName = "set" + key.substring(0, 1).toUpperCase(Locale.ENGLISH) + key.substring(1); try { // Can we work with whatever type we were given? Method method = real.getMethod(setterName, new Class[] { value.getClass() }); method.invoke(object, new Object[] { value }); return; } catch (NoSuchMethodException ex) { // If it is a string then next we try to coerce it to the right type // otherwise we give up. if (!(value instanceof String)) { throw ex; } } Method[] methods = real.getMethods(); for (int i = 0; i < methods.length; i++) { Method setter = methods[i]; if (setter.getName().equals(setterName) && setter.getParameterTypes().length == 1) { Class propertyType = setter.getParameterTypes()[0]; try { Object param = LocalUtil.simpleConvert((String) value, propertyType); setter.invoke(object, new Object[] { param }); return; } catch (IllegalArgumentException ex) { // The conversion failed - it was speculative anyway so we // don‘t worry now } } } throw new NoSuchMethodException("Failed to find a property called: " + key + " on " + object.getClass().getName()); } /** * Can the type be used in a call to {@link #simpleConvert(String, Class)}? * @param paramType The type to test * @return true if the type is acceptable to simpleConvert() */ public static boolean isTypeSimplyConvertable(Class paramType) { return paramType == String.class || paramType == Integer.class || paramType == Integer.TYPE || paramType == Short.class || paramType == Short.TYPE || paramType == Byte.class || paramType == Byte.TYPE || paramType == Long.class || paramType == Long.TYPE || paramType == Float.class || paramType == Float.TYPE || paramType == Double.class || paramType == Double.TYPE || paramType == Character.class || paramType == Character.TYPE || paramType == Boolean.class || paramType == Boolean.TYPE; } /** * A very simple conversion function for all the IoC style setup and * reflection that we are doing. * @param value The value to convert * @param paramType The type to convert to. Currently ony primitive types and * String are supported. * @return The converted object. */ public static Object simpleConvert(String value, Class paramType) { if (paramType == String.class) { return value; } if (paramType == Character.class || paramType == Character.TYPE) { if (value.length() == 1) { return new Character(value.charAt(0)); } else { throw new IllegalArgumentException("Can‘t more than one character in string - can‘t convert to char: ‘" + value + "‘"); } } String trimValue = value.trim(); if (paramType == Boolean.class) { if (trimValue.length() == 0) { return null; } return Boolean.valueOf(trimValue); } if (paramType == Boolean.TYPE) { return Boolean.valueOf(trimValue); } if (paramType == Integer.class) { if (trimValue.length() == 0) { return null; } return Integer.valueOf(trimValue); } if (paramType == Integer.TYPE) { if (trimValue.length() == 0) { return new Integer(0); } return Integer.valueOf(trimValue); } if (paramType == Short.class) { if (trimValue.length() == 0) { return null; } return Short.valueOf(trimValue); } if (paramType == Short.TYPE) { if (trimValue.length() == 0) { return new Short((short) 0); } return Short.valueOf(trimValue); } if (paramType == Byte.class) { if (trimValue.length() == 0) { return null; } return Byte.valueOf(trimValue); } if (paramType == Byte.TYPE) { if (trimValue.length() == 0) { return new Byte((byte) 0); } return Byte.valueOf(trimValue); } if (paramType == Long.class) { if (trimValue.length() == 0) { return null; } return Long.valueOf(trimValue); } if (paramType == Long.TYPE) { if (trimValue.length() == 0) { return new Long(0); } return Long.valueOf(trimValue); } if (paramType == Float.class) { if (trimValue.length() == 0) { return null; } return Float.valueOf(trimValue); } if (paramType == Float.TYPE) { if (trimValue.length() == 0) { return new Float(0); } return Float.valueOf(trimValue); } if (paramType == Double.class) { if (trimValue.length() == 0) { return null; } return Double.valueOf(trimValue); } if (paramType == Double.TYPE) { if (trimValue.length() == 0) { return new Double(0); } return Double.valueOf(trimValue); } throw new IllegalArgumentException("Unsupported conversion type: " + paramType.getName()); } /** * 得到除去包名的类名。 * * Get the short class name (i.e. without the package part) * @param clazz the class to get the short name of * @return the class name of the class without the package name */ public static String getShortClassName(Class clazz) { String className = clazz.getName(); char[] chars = className.toCharArray(); int lastDot = 0; for (int i = 0; i < chars.length; i++) { if (chars[i] == ‘.‘) { lastDot = i + 1; } else if (chars[i] == ‘$‘) { chars[i] = ‘.‘; } } // This might come up in scans for locale/charset issues. It‘s not an // issue since we are talking about chars. return new String(chars, lastDot, chars.length - lastDot); } /** * Is this object property one that we can use in a JSON style or do we need * to get fancy. i.e does it contain only letters and numbers with an * initial letter. * @param name The name to test for JSON compatibility * @return true if the name is simple */ public static boolean isSimpleName(String name) { if (name.length() == 0) { return false; } if (JavascriptUtil.isReservedWord(name)) { return false; } boolean isSimple = Character.isLetter(name.charAt(0)); for (int i = 1; isSimple && i < name.length(); i++) { if (!Character.isLetterOrDigit(name.charAt(i))) { isSimple = false; } } return isSimple; } /** * Utility to essentially do Class forName and allow configurable * Classloaders. * <p>The initial implementation makes use of the context classloader for * the current thread. * @param className The class to create * @return The class if it is safe or null otherwise. * @throws ClassNotFoundException If <code>className</code> is not valid */ public static Class classForName(String className) throws ClassNotFoundException { // Class.forName(className); return Thread.currentThread().getContextClassLoader().loadClass(className); } /** * Calling methods using reflection is useful for graceful fallback - this * is a helper method to make this easy * @param object The object to use as ‘this‘ * @param method The method to call, can be null in which case null is returned * @param params The parameters to pass to the reflection call * @return The results of calling method.invoke() or null * @throws IllegalStateException If anything goes wrong */ public static Object invoke(Object object, Method method, Object[] params) throws IllegalStateException { Object reply = null; if (method != null) { try { reply = method.invoke(object, params); } catch (InvocationTargetException ex) { throw new IllegalStateException("InvocationTargetException calling " + method.getName() + ": " + ex.getTargetException().toString()); } catch (Exception ex) { throw new IllegalStateException("Reflection error calling " + method.getName() + ": " + ex.toString()); } } return reply; } /** * Utility to essentially do Class forName with the assumption that the * environment expects failures for missing jar files and can carry on if * this process fails. * @param name The name for debugging purposes * @param className The class to create * @param impl The implementation class - what should className do? * @return The class if it is safe or null otherwise. */ public static Class classForName(String name, String className, Class impl) { Class clazz; try { clazz = classForName(className); } catch (ClassNotFoundException ex) { // We expect this sometimes, hence debug log.debug("Skipping ‘" + name + "‘ due to ClassNotFoundException on " + className + ". Cause: " + ex.getMessage()); return null; } catch (NoClassDefFoundError ex) { // We expect this sometimes, hence debug log.debug("Skipping ‘" + name + "‘ due to NoClassDefFoundError on " + className + ". Cause: " + ex.getMessage()); return null; } catch (TransformerFactoryConfigurationError ex) { // We expect this sometimes, hence debug log.debug("Skipping ‘" + name + "‘ due to TransformerFactoryConfigurationError on " + className + ". Cause: " + ex.getMessage()); log.debug("Maybe you need to add xalan.jar to your webserver?"); return null; } // Check it is of the right type if (!impl.isAssignableFrom(clazz)) { log.error("Class ‘" + clazz.getName() + "‘ does not implement ‘" + impl.getName() + "‘."); return null; } // Check we can create it try { clazz.newInstance(); } catch (InstantiationException ex) { log.error("InstantiationException for ‘" + name + "‘ failed:", ex); return null; } catch (IllegalAccessException ex) { log.error("IllegalAccessException for ‘" + name + "‘ failed:", ex); return null; } catch (NoClassDefFoundError ex) { // We expect this sometimes, hence debug log.debug("Skipping ‘" + name + "‘ due to NoClassDefFoundError on " + className + ". Cause: " + ex.getMessage()); return null; } catch (TransformerFactoryConfigurationError ex) { // We expect this sometimes, hence debug log.debug("Skipping ‘" + name + "‘ due to TransformerFactoryConfigurationError on " + className + ". Cause: " + ex.getMessage()); log.debug("Maybe you need to add xalan.jar to your webserver?"); return null; } catch (Exception ex) { // For some reason we can‘t catch this? if (ex instanceof ClassNotFoundException) { // We expect this sometimes, hence debug log.debug("Skipping ‘" + name + "‘ due to ClassNotFoundException on " + className + ". Cause: " + ex.getMessage()); return null; } else { log.error("Failed to load ‘" + name + "‘ (" + className + ")", ex); return null; } } return clazz; } /** * Utility to essentially do Class forName and newInstance with the * assumption that the environment expects failures for missing jar files * and can carry on if this process fails. * @param name The name for debugging purposes * @param className The class to create * @param impl The implementation class - what should className do? * @return The new instance if it is safe or null otherwise. */ public static Object classNewInstance(String name, String className, Class impl) { Class clazz; try { clazz = LocalUtil.classForName(className); } catch (ClassNotFoundException ex) { // We expect this sometimes, hence debug log.debug("Skipping ‘" + name + "‘ due to ClassNotFoundException on " + className + ". Cause: " + ex.getMessage()); return null; } catch (NoClassDefFoundError ex) { // We expect this sometimes, hence debug log.debug("Skipping ‘" + name + "‘ due to NoClassDefFoundError on " + className + ". Cause: " + ex.getMessage()); return null; } catch (TransformerFactoryConfigurationError ex) { // We expect this sometimes, hence debug log.debug("Skipping ‘" + name + "‘ due to TransformerFactoryConfigurationError on " + className + ". Cause: " + ex.getMessage()); return null; } // Check it is of the right type if (!impl.isAssignableFrom(clazz)) { log.error("Class ‘" + clazz.getName() + "‘ does not implement ‘" + impl.getName() + "‘."); return null; } // Check we can create it try { return clazz.newInstance(); } catch (InstantiationException ex) { log.error("InstantiationException for ‘" + name + "‘ failed:", ex); return null; } catch (IllegalAccessException ex) { log.error("IllegalAccessException for ‘" + name + "‘ failed:", ex); return null; } catch (TransformerFactoryConfigurationError ex) { log.error("TransformerFactoryConfigurationError for ‘" + name + "‘ failed:", ex); return null; } catch (Exception ex) { log.error("Failed to load creator ‘" + name + "‘, classname=" + className + ": ", ex); return null; } } /** * InputStream closer that can cope if the input stream is null. * If anything goes wrong, the errors are logged and ignored. * @param in The resource to close */ public static void close(InputStream in) { if (in == null) { return; } try { in.close(); } catch (IOException ex) { log.warn(ex.getMessage(), ex); } } /** * InputStream closer that can cope if the input stream is null. * If anything goes wrong, the errors are logged and ignored. * @param in The resource to close */ public static void close(Reader in) { if (in == null) { return; } try { in.close(); } catch (IOException ex) { log.warn(ex.getMessage(), ex); } } /** * InputStream closer that can cope if the input stream is null. * If anything goes wrong, the errors are logged and ignored. * @param in The resource to close */ public static void close(RandomAccessFile in) { if (in == null) { return; } try { in.close(); } catch (IOException ex) { log.warn(ex.getMessage(), ex); } } /** * Return a List of superclasses for the given class. * @param clazz the class to look up * @return the List of superclasses in order going up from this one */ public static List getAllSuperclasses(Class clazz) { List classes = new ArrayList(); Class superclass = clazz.getSuperclass(); while (superclass != null) { classes.add(superclass); superclass = superclass.getSuperclass(); } return classes; } /** * Return a list of all fields (whatever access status, and on whatever * superclass they were defined) that can be found on this class. * <p>This is like a union of {@link Class#getDeclaredFields()} which * ignores and superclasses, and {@link Class#getFields()} which ignored * non-pubic fields * @param clazz The class to introspect * @return The complete list of fields */ public static Field[] getAllFields(Class clazz) { List classes = getAllSuperclasses(clazz); classes.add(clazz); return getAllFields(classes); } /** * As {@link #getAllFields(Class)} but acts on a list of {@link Class}s and * uses only {@link Class#getDeclaredFields()}. * @param classes The list of classes to reflect on * @return The complete list of fields */ private static Field[] getAllFields(List classes) { Set fields = new HashSet(); for (Iterator it = classes.iterator(); it.hasNext();) { Class clazz = (Class) it.next(); fields.addAll(Arrays.asList(clazz.getDeclaredFields())); } return (Field[]) fields.toArray(new Field[fields.size()]); } /** * The log stream */ private static final Logger log = Logger.getLogger(LocalUtil.class); /** * Have we given a warning about URLDecoder.decode() in jdk 1.3 */ private static boolean warn13 = false; /** * Have we tested for the correct URLDecoder.decode() */ private static boolean testedDecoder = false; /** * Are we using the jdk 1.4 version of URLDecoder.decode() */ private static Method decode14 = null;}
声明:以上内容来自用户投稿及互联网公开渠道收集整理发布,本网站不拥有所有权,未作人工编辑处理,也不承担相关法律责任,若内容有误或涉及侵权可进行投诉: 投诉/举报 工作人员会在5个工作日内联系你,一经查实,本站将立刻删除涉嫌侵权内容。