java反射工具类
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.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.util.Assert;/** * 反射工具类. ** 提供访问私有变量,获取泛型类型Class, 提取集合中元素的属性, 转换字符串到对象等Util函数. **/public class ReflectionUtils {private static Logger logger = LoggerFactory.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);}/** * 调用Getter方法. */public static Object invokeGetterMethod(Object target, String propertyName) {String getterMethodName = "get" + StringUtils.capitalize(propertyName);return invokeMethod(target, getterMethodName, new Class[] {}, new Object[] {});}/** * 调用Setter方法.使用value的Class来查找Setter方法. */public static void invokeSetterMethod(Object target, String propertyName, Object value) {invokeSetterMethod(target, propertyName, value, null);}/** * 调用Setter方法. ** @param propertyType 用于查找Setter方法,为空时使用value的Class替代. */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 });}/** * 直接读取对象属性值, 无视private/protected修饰符, 不经过getter函数. */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("不可能抛出的异常{}", e.getMessage());}return result;}/** * 直接设置对象属性值, 无视private/protected修饰符, 不经过setter函数. */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("不可能抛出的异常:{}", e.getMessage());}}/** * 直接调用对象方法, 无视private/protected修饰符. */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);}}/** * 循环向上转型, 获取对象的DeclaredField. ** 如向上转型到Object仍无法找到, 返回null. */protected static Field getDeclaredField(final Object object, final String fieldName) {Assert.notNull(object, "object不能为空");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不在当前类定义,继续向上转型}}return null;}/** * 强行设置Field可访问. */protected static void makeAccessible(final Field field) {if (!Modifier.isPublic(field.getModifiers()) || !Modifier.isPublic(field.getDeclaringClass().getModifiers())) {field.setAccessible(true);}}/** * 循环向上转型, 获取对象的DeclaredMethod. ** 如向上转型到Object仍无法找到, 返回null. */protected static Method getDeclaredMethod(Object object, String methodName, Class<?>[] parameterTypes) {Assert.notNull(object, "object不能为空");for (Class<?> superClass = object.getClass(); superClass != Object.class; superClass = superClass.getSuperclass()) {try {return superClass.getDeclaredMethod(methodName, parameterTypes);} catch (NoSuchMethodException e) {//NOSONAR// Method不在当前类定义,继续向上转型}}return null;}/** * 通过反射, 获得Class定义中声明的父类的泛型参数的类型. * 如无法找到, 返回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);}/** * 通过反射, 获得定义Class时声明的父类的泛型参数的类型. * 如无法找到, 返回Object.class. ** 如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 instanceof Class)) {logger.warn(clazz.getSimpleName() + " not set the actual class on superclass generic parameter");return Object.class;}return (Class) params;}/** * 提取集合中的对象的属性(通过getter函数), 组合成List. ** @param collection 来源集合. * @param propertyName 要提取的属性名. */@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;}/** * 提取集合中的对象的属性(通过getter函数), 组合成由分割符分隔的字符串. ** @param collection 来源集合. * @param propertyName 要提取的属性名. * @param separator 分隔符. */@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);}/** * 转换字符串到相应类型. ** @param value 待转换的字符串 * @param toType 转换目标类型 */@SuppressWarnings("unchecked")public static <T> T convertStringToObject(String value, Class<T> toType) {try {return (T) ConvertUtils.convert(value, toType);} catch (Exception e) {throw convertReflectionExceptionToUnchecked(e);}}/** * 将反射时的checked exception转换为unchecked exception. */public static RuntimeException convertReflectionExceptionToUnchecked(Exception e) {return convertReflectionExceptionToUnchecked(null, e);}public static RuntimeException convertReflectionExceptionToUnchecked(String desc, Exception e) {desc = (desc == null) ? "Unexpected Checked Exception." : desc;if (e instanceof IllegalAccessException || e instanceof IllegalArgumentException|| e instanceof NoSuchMethodException) {return new IllegalArgumentException(desc, e);} else if (e instanceof InvocationTargetException) {return new RuntimeException(desc, ((InvocationTargetException) e).getTargetException());} else if (e instanceof RuntimeException) {return (RuntimeException) e;}return new RuntimeException(desc, e);}public static final <T> T getNewInstance(Class<T> cls) {try {return cls.newInstance();} catch (InstantiationException e) {e.printStackTrace();} catch (IllegalAccessException e) {e.printStackTrace();}return null;}}
页:
[1]