ReflectionUtils

ReflectionUtils
2011年07月01日
　　 import java.lang.reflect.Field; 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.HashSet; import java.util.List; import java.util.Set; import org.apache.commons.beanutils.PropertyUtils; import org.apache.commons.lang.StringUtils; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.util.Assert; /** * 反射的Utils函数集合. * * 提供访问私有变量,获取泛型类型Class,提取集合中元素的属性等Utils函数. * * @author calvin */ public class ReflectionUtils { private static Logger logger = LoggerFactory.getLogger(ReflectionUtils.class); private ReflectionUtils() { } /** * 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; } /** * 清除对像中的所有Collection对像 * @param object * @return */ public static Object clearCollection(Object object){ Class c = object.getClass(); Method[] methods=c.getMethods(); for (Method method:methods) { Class[] interfaces=method.getReturnType().getInterfaces(); for (Class tempInterface : interfaces) { if(tempInterface.equals(Collection.class)){ String fieldName=StringUtils.replaceOnce(method.getName() ,"get",""); fieldName=StringUtils.uncapitalize(fieldName); setFieldValue(object, fieldName, null); } } } return object; } /** * 请除对像中指定的Collection属性 * @param object * @param fieldNames * @return */ public static Object clearCollection(Object object,String... fieldNames){ Class c = object.getClass(); Method[] methods=c.getMethods(); for (Method method:methods) { Class[] interfaces=method.getReturnType().getInterfaces(); for (Class tempInterface : interfaces) { if(tempInterface.equals(Collection.class)){ for (String targetField : fieldNames) { String fieldName=StringUtils.replaceOnce(method.getName() ,"get",""); fieldName=StringUtils.uncapitalize(fieldName); if(fieldName.equals(targetField)){ setFieldValue(object, fieldName, null); } } } } } return object; } /** * 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()); } } /** * 循环向上转型,获取对象的DeclaredField. */ protected static Field getDeclaredField(final Object object, final String fieldName) { Assert.notNull(object, "object不能为空"); return getDeclaredField(object.getClass(), fieldName); } /** * 循环向上转型,获取类的DeclaredField. */ @SuppressWarnings("unchecked") protected static Field getDeclaredField(final Class clazz, final String fieldName) { Assert.notNull(clazz, "clazz不能为空"); Assert.hasText(fieldName, "fieldName"); for (Class superClass = clazz; superClass != Object.class; superClass = superClass.getSuperclass()) { try { return superClass.getDeclaredField(fieldName); } catch (NoSuchFieldException e) { // Field不在当前类定义,继续向上转型 } } return null; } /** * 强制转换fileld可访问. */ protected static void makeAccessible(final Field field) { if (!Modifier.isPublic(field.getModifiers()) || !Modifier.isPublic(field.getDeclaringClass().getMo difiers())) { field.setAccessible(true); } } /** * 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 UserDao extends HibernateDao * * @param clazz The class to introspect * @return the first generic declaration, or Object.class if cannot be determined */ @SuppressWarnings("unchecked") public static Class 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public UserDao extends HibernateDao * * @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