Java 反射工具类 ReflectionUtil

import lombok.extern.slf4j.Slf4j; import java.lang.reflect.*; /** * 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 */ @Slf4j public class ReflectionUtils { /** * 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) { log.error("getFieldValue:", e); } return result; } /** * 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) { log.error("setFieldValue:", e); } } /** * 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 { 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) { log.error("invokeMethod:", e); } return null; } }