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;/*** 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* @author Administrator**/
public class ReflectionUtils {/*** 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) {System.out.println("不可能抛出的异常");} 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) {System.out.println("不可能抛出的异常");}}/*** 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) {System.out.println("不可能抛出的异常");}return result;}
}