Java tutorial
package com.cxypub.baseframework.sdk.util; /** * Copyright (c) 2005-2009 springside.org.cn * * Licensed under the Apache License, Version 2.0 (the "License"); * * $Id: ReflectionUtils.java 969 2010-03-01 14:50:35Z calvinxiu $ */ import java.lang.reflect.Field; import java.lang.reflect.InvocationTargetException; import java.lang.reflect.Method; import java.lang.reflect.Modifier; import java.lang.reflect.ParameterizedType; import java.lang.reflect.Type; import java.util.ArrayList; import java.util.Collection; import java.util.Date; import java.util.List; import org.apache.commons.beanutils.ConvertUtils; import org.apache.commons.beanutils.PropertyUtils; import org.apache.commons.beanutils.converters.DateConverter; import org.apache.commons.lang.StringUtils; import org.apache.log4j.Logger; import org.springframework.util.Assert; /** * SringSide?? * * ?????,?Class, ????, ?Util. * * @author calvin */ public class ReflectionUtils { private static Logger logger = Logger.getLogger(ReflectionUtils.class); static { DateConverter dc = new DateConverter(); dc.setUseLocaleFormat(true); dc.setPatterns(new String[] { "yyyy-MM-dd", "yyyy-MM-dd HH:mm:ss" }); ConvertUtils.register(dc, Date.class); } /** * Getter. */ public static Object invokeGetterMethod(Object target, String propertyName) { String getterMethodName = "get" + StringUtils.capitalize(propertyName); return invokeMethod(target, getterMethodName, new Class[] {}, new Object[] {}); } /** * Setter.valueClass?Setter. */ public static void invokeSetterMethod(Object target, String propertyName, Object value) { invokeSetterMethod(target, propertyName, value, null); } /** * Setter. * * @param propertyType Setter,valueClass. */ public static void invokeSetterMethod(Object target, String propertyName, Object value, Class<?> propertyType) { Class<?> type = propertyType != null ? propertyType : value.getClass(); String setterMethodName = "set" + StringUtils.capitalize(propertyName); invokeMethod(target, setterMethodName, new Class[] { type }, new Object[] { value }); } /** * ?, private/protected, ??getter. */ public static Object getFieldValue(final Object object, final String fieldName) { Field field = getDeclaredField(object, fieldName); if (field == null) { throw new IllegalArgumentException( "Could not find field [" + fieldName + "] on target [" + object + "]"); } makeAccessible(field); Object result = null; try { result = field.get(object); } catch (IllegalAccessException e) { logger.error("??:" + e.getMessage()); } return result; } /** * , private/protected, ??setter. */ public static void setFieldValue(final Object object, final String fieldName, final Object value) { Field field = getDeclaredField(object, fieldName); if (field == null) { throw new IllegalArgumentException( "Could not find field [" + fieldName + "] on target [" + object + "]"); } makeAccessible(field); try { field.set(object, value); } catch (IllegalAccessException e) { logger.error("??:" + e.getMessage()); } } /** * , private/protected. */ public static Object invokeMethod(final Object object, final String methodName, final Class<?>[] parameterTypes, final Object[] parameters) { Method method = getDeclaredMethod(object, methodName, parameterTypes); if (method == null) { throw new IllegalArgumentException( "Could not find method [" + methodName + "] on target [" + object + "]"); } method.setAccessible(true); try { return method.invoke(object, parameters); } catch (Exception e) { throw convertReflectionExceptionToUnchecked(e); } } /** * ?, ?DeclaredField. * * ?Object?, null. */ protected static Field getDeclaredField(final Object object, final String fieldName) { Assert.notNull(object, "object?"); Assert.hasText(fieldName, "fieldName"); for (Class<?> superClass = object.getClass(); superClass != Object.class; superClass = superClass .getSuperclass()) { try { return superClass.getDeclaredField(fieldName); } catch (NoSuchFieldException e) {// NOSONAR // Field??,? } } return null; } /** * Field?. */ protected static void makeAccessible(final Field field) { if (!Modifier.isPublic(field.getModifiers()) || !Modifier.isPublic(field.getDeclaringClass().getModifiers())) { field.setAccessible(true); } } /** * ?, ?DeclaredMethod. * * ?Object?, null. */ protected static Method getDeclaredMethod(Object object, String methodName, Class<?>[] parameterTypes) { Assert.notNull(object, "object?"); for (Class<?> superClass = object.getClass(); superClass != Object.class; superClass = superClass .getSuperclass()) { try { return superClass.getDeclaredMethod(methodName, parameterTypes); } catch (NoSuchMethodException e) {// NOSONAR // Method??,? } } return null; } /** * ??, Class?. * , Object.class. * eg. * public UserDao extends HibernateDao<User> * * @param clazz The class to introspect * @return the first generic declaration, or Object.class if cannot be determined */ @SuppressWarnings("unchecked") public static <T> Class<T> getSuperClassGenricType(final Class<?> clazz) { return getSuperClassGenricType(clazz, 0); } /** * ??, Class?. * , Object.class. * * public UserDao extends HibernateDao<User,Long> * * @param clazz clazz The class to introspect * @param index the Index of the generic ddeclaration,start from 0. * @return the index generic declaration, or Object.class if cannot be determined */ @SuppressWarnings("unchecked") public static Class getSuperClassGenricType(final Class clazz, final int index) { Type genType = clazz.getGenericSuperclass(); if (!(genType instanceof ParameterizedType)) { logger.warn(clazz.getSimpleName() + "'s superclass not ParameterizedType"); return Object.class; } Type[] params = ((ParameterizedType) genType).getActualTypeArguments(); if (index >= params.length || index < 0) { logger.warn("Index: " + index + ", Size of " + clazz.getSimpleName() + "'s Parameterized Type: " + params.length); return Object.class; } if (!(params[index] instanceof Class)) { logger.warn(clazz.getSimpleName() + " not set the actual class on superclass generic parameter"); return Object.class; } return (Class) params[index]; } /** * ????(getter), ??List. * * @param collection ???. * @param propertyName ??????. */ @SuppressWarnings("unchecked") public static List convertElementPropertyToList(final Collection collection, final String propertyName) { List list = new ArrayList(); try { for (Object obj : collection) { list.add(PropertyUtils.getProperty(obj, propertyName)); } } catch (Exception e) { throw convertReflectionExceptionToUnchecked(e); } return list; } /** * ????(getter), ??. * * @param collection ???. * @param propertyName ??????. * @param separator . */ @SuppressWarnings("unchecked") public static String convertElementPropertyToString(final Collection collection, final String propertyName, final String separator) { List list = convertElementPropertyToList(collection, propertyName); return StringUtils.join(list, separator); } /** * ?. * * @param value ? * @param toType ? */ public static Object convertStringToObject(String value, Class<?> toType) { try { return ConvertUtils.convert(value, toType); } catch (Exception e) { throw convertReflectionExceptionToUnchecked(e); } } /** * ??checked exception?unchecked exception. */ public static RuntimeException convertReflectionExceptionToUnchecked(Exception e) { if (e instanceof IllegalAccessException || e instanceof IllegalArgumentException || e instanceof NoSuchMethodException) { return new IllegalArgumentException("Reflection Exception.", e); } else if (e instanceof InvocationTargetException) { return new RuntimeException("Reflection Exception.", ((InvocationTargetException) e).getTargetException()); } else if (e instanceof RuntimeException) { return (RuntimeException) e; } return new RuntimeException("Unexpected Checked Exception.", e); } /** * ?, ?DeclaredMethod,?. ?Object?, null. * * ?. ?Method,?Method.invoke(Object obj, Object... * args) */ public static Method getAccessibleMethod(final Object obj, final String methodName, final Class<?>... parameterTypes) { Assert.notNull(obj, "object?"); for (Class<?> superClass = obj.getClass(); superClass != Object.class; superClass = superClass .getSuperclass()) { try { Method method = superClass.getDeclaredMethod(methodName, parameterTypes); method.setAccessible(true); return method; } catch (NoSuchMethodException e) {// NOSONAR // Method??,? } } return null; } }