ReflectionUtils工具类代码

package cn.itcast.java.utils;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; /** * * 反射的 Utils 函数集合 * 提供访问私有变量, 获取泛型类型 Class, 提取集合中元素属性等 Utils 函数 * */public class ReflectionUtils {/** * 将反射时的 "检查异常" 转换为 "运行时异常" * @return */public static IllegalArgumentException convertToUncheckedException(Exception ex){if(ex instanceof IllegalAccessException || ex instanceof IllegalArgumentException|| ex instanceof NoSuchMethodException){throw new IllegalArgumentException("反射异常", ex);}else{throw new IllegalArgumentException(ex);}}/** * 转换字符串类型到 toType 类型, 或 toType 转为字符串 * @param value: 待转换的字符串 * @param toType: 提供类型信息的 Class, 可以是基本数据类型的包装类或指定格式日期型 * @return */public static Object convertValue(Object value, Class<?> toType){try {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);return ConvertUtils.convert(value, toType);} catch (Exception e) {e.printStackTrace();throw convertToUncheckedException(e);}}/** * 提取集合中的对象的属性(通过 getter 方法), 组成 List * @param collection: 来源集合 * @param propertyName: 要提取的属性名 * @return */@SuppressWarnings("unchecked")public static List fetchElementPropertyToList(Collection collection, String propertyName){List list = new ArrayList();try {for(Object obj: collection){list.add(PropertyUtils.getProperty(obj, propertyName));}} catch (Exception e) {e.printStackTrace();convertToUncheckedException(e);}return list;}/** * 提取集合中的对象属性(通过 getter 函数), 组合成由分隔符分隔的字符串 * @param collection: 来源集合 * @param propertyName: 要提取的属性名 * @param seperator: 分隔符 * @return */@SuppressWarnings("unchecked")public static String fetchElementPropertyToString(Collection collection, String propertyName, String seperator){List list = fetchElementPropertyToList(collection, propertyName);return StringUtils.join(list, seperator);}/** * 通过反射, 获得定义 Class 时声明的父类的泛型参数的类型 * 如: public EmployeeDao extends BaseDao<Employee, String> * @param clazz * @param index * @return */@SuppressWarnings("unchecked")public static Class getSuperClassGenricType(Class clazz, int index){Type genType = clazz.getGenericSuperclass();if(!(genType instanceof ParameterizedType)){return Object.class;}Type [] params = ((ParameterizedType)genType).getActualTypeArguments();if(index >= params.length || index < 0){return Object.class;}if(!(params[index] instanceof Class)){return Object.class;}return (Class) params[index];}/** * 通过反射, 获得 Class 定义中声明的父类的泛型参数类型 * 如: public EmployeeDao extends BaseDao<Employee, String> * @param <T> * @param clazz * @return */@SuppressWarnings("unchecked")public static<T> Class<T> getSuperGenericType(Class clazz){return getSuperClassGenricType(clazz, 0);}/** * 循环向上转型, 获取对象的 DeclaredMethod * @param object * @param methodName * @param parameterTypes * @return */public static Method getDeclaredMethod(Object object, String methodName, Class<?>[] parameterTypes){for(Class<?> superClass = object.getClass(); superClass != Object.class; superClass = superClass.getSuperclass()){try {//superClass.getMethod(methodName, parameterTypes);return superClass.getDeclaredMethod(methodName, parameterTypes);} catch (NoSuchMethodException e) {//Method 不在当前类定义, 继续向上转型}//..}return null;}/** * 使 filed 变为可访问 * @param field */public static void makeAccessible(Field field){if(!Modifier.isPublic(field.getModifiers())){field.setAccessible(true);}}/** * 循环向上转型, 获取对象的 DeclaredField * @param object * @param filedName * @return */public static Field getDeclaredField(Object object, String filedName){for(Class<?> superClass = object.getClass(); superClass != Object.class; superClass = superClass.getSuperclass()){try {return superClass.getDeclaredField(filedName);} catch (NoSuchFieldException e) {//Field 不在当前类定义, 继续向上转型}}return null;}/** * 直接调用对象方法, 而忽略修饰符(private, protected) * @param object * @param methodName * @param parameterTypes * @param parameters * @return * @throws InvocationTargetException * @throws IllegalArgumentException */public static Object invokeMethod(Object object, String methodName, Class<?> [] parameterTypes,Object [] parameters) throws InvocationTargetException{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(IllegalAccessException e) {} return null;}/** * 直接设置对象属性值, 忽略 private/protected 修饰符, 也不经过 setter * @param object * @param fieldName * @param value */public static void setFieldValue(Object object, String fieldName, 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) {}}/** * 直接读取对象的属性值, 忽略 private/protected 修饰符, 也不经过 getter * @param object * @param fieldName * @return */public static Object getFieldValue(Object object, 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) {}return result;}}