Java tutorial
/******************************************************************************* * Copyright (c) 2005, 2014 springside.github.io * * Licensed under the Apache License, Version 2.0 (the "License"); *******************************************************************************/ package com.mine.core.util; 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.Proxy; import java.lang.reflect.Type; import java.util.List; import org.apache.commons.lang3.StringUtils; import org.apache.commons.lang3.Validate; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import com.google.common.collect.Lists; /** * ??. * <p> * ??getter/setter, ???, ?, ?Class, AOP. * * @author calvin */ public class ReflectUtils { private static final String SETTER_PREFIX = "set"; private static final String GETTER_PREFIX = "get"; private static final String CGLIB_CLASS_SEPARATOR = "$$"; private static final String ERROR_BLOCK = "] on target ["; private static Logger logger = LoggerFactory.getLogger(ReflectUtils.class); private ReflectUtils() { } /** * Getter. */ public static Object invokeGetter(Object obj, String propertyName) { String getterMethodName = GETTER_PREFIX + StringUtils.capitalize(propertyName); return invokeMethod(obj, getterMethodName, new Class[] {}, new Object[] {}); } /** * Setter, ??? */ public static void invokeSetter(Object obj, String propertyName, Object value) { String setterMethodName = SETTER_PREFIX + StringUtils.capitalize(propertyName); invokeMethodByName(obj, setterMethodName, new Object[] { value }); } /** * ?, private/protected, ??getter. */ public static Object getFieldValue(final Object obj, final String fieldName) { return getFieldValue(obj, fieldName, false); } public static Object getFieldValue(final Object obj, final String fieldName, boolean ignoreNotFond) { Field field = getAccessibleField(obj, fieldName); if (field == null) { if (ignoreNotFond) { return null; } else { throw new IllegalArgumentException("Could not find field [" + fieldName + ERROR_BLOCK + obj + "]"); } } Object result = null; try { result = field.get(obj); } catch (IllegalAccessException e) { logger.error("??{}", e.getMessage()); } return result; } /** * , private/protected, ??setter. */ public static void setFieldValue(final Object obj, final String fieldName, final Object value) { setFieldValue(obj, fieldName, value, false); } /** * , private/protected, ??setter. ignoreNotFond-not found * fieldName */ public static void setFieldValue(final Object obj, final String fieldName, final Object value, boolean ignoreNotFond) { Field field = getAccessibleField(obj, fieldName); if (field == null) { if (ignoreNotFond) { return; } else { throw new IllegalArgumentException("Could not find field [" + fieldName + ERROR_BLOCK + obj + "]"); } } try { field.set(obj, value); } catch (IllegalAccessException e) { logger.error("??:{}", e.getMessage()); } } /** * , private/protected. * ?getAccessibleMethod()Method????. ????+? */ public static Object invokeMethod(final Object obj, final String methodName, final Class<?>[] parameterTypes, final Object[] args) { Method method = getAccessibleMethod(obj, methodName, parameterTypes); if (method == null) { throw new IllegalArgumentException("Could not find method [" + methodName + ERROR_BLOCK + obj + "]"); } try { return method.invoke(obj, args); } catch (Exception e) { throw convertReflectionExceptionToUnchecked(e); } } /** * , private/protected * ?getAccessibleMethodByName()Method????. * ??????? */ public static Object invokeMethodByName(final Object obj, final String methodName, final Object[] args) { Method method = getAccessibleMethodByName(obj, methodName); if (method == null) { throw new IllegalArgumentException("Could not find method [" + methodName + ERROR_BLOCK + obj + "]"); } try { return method.invoke(obj, args); } catch (Exception e) { throw convertReflectionExceptionToUnchecked(e); } } /** * ?, ?DeclaredField, ?. * <p> * ?Object?, null. */ public static Field getAccessibleField(final Object obj, final String fieldName) { Validate.notNull(obj); Validate.notBlank(fieldName, "fieldName can't be blank"); for (Class<?> superClass = obj.getClass(); superClass != Object.class; superClass = superClass .getSuperclass()) { try { Field field = superClass.getDeclaredField(fieldName); makeAccessible(field); return field; } catch (NoSuchFieldException e) {// NOSONAR // Field??,? } } return null; } /** * ?, ?DeclaredMethod,?. ?Object?, null. * ???+? * <p> * ?. ?Method,?Method.invoke(Object obj, Object... * args) */ public static Method getAccessibleMethod(final Object obj, final String methodName, final Class<?>... parameterTypes) { Validate.notNull(obj); Validate.notBlank(methodName); for (Class<?> searchType = obj.getClass(); searchType != Object.class; searchType = searchType .getSuperclass()) { try { Method method = searchType.getDeclaredMethod(methodName, parameterTypes); makeAccessible(method); return method; } catch (NoSuchMethodException e) { // Method??,? } } return null; } /** * ?, ?DeclaredMethod,?. ?Object?, null. ???? * <p> * ?. ?Method,?Method.invoke(Object obj, Object... * args) */ public static Method getAccessibleMethodByName(final Object obj, final String methodName) { Validate.notNull(obj); Validate.notBlank(methodName); for (Class<?> searchType = obj.getClass(); searchType != Object.class; searchType = searchType .getSuperclass()) { Method[] methods = searchType.getDeclaredMethods(); for (Method method : methods) { if (method.getName().equals(methodName)) { makeAccessible(method); return method; } } } return null; } /** * ?private/protectedpublic?????JDKSecurityManager */ public static void makeAccessible(Method method) { if ((!Modifier.isPublic(method.getModifiers()) || !Modifier.isPublic(method.getDeclaringClass().getModifiers())) && !method.isAccessible()) { method.setAccessible(true); } } /** * ?private/protected???public?????JDKSecurityManager */ public static void makeAccessible(Field field) { if ((!Modifier.isPublic(field.getModifiers()) || !Modifier.isPublic(field.getDeclaringClass().getModifiers()) || Modifier.isFinal(field.getModifiers())) && !field.isAccessible()) { field.setAccessible(true); } } /** * ??, Class?, ? , 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 */ public static <T> Class<T> getClassGenricType(final Class clazz) { return getClassGenricType(clazz, 0); } /** * ??, Class?. , Object.class. * <p> * 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 */ public static Class getClassGenricType(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: {}, Size of {}'s Parameterized Type: {}", index, clazz.getSimpleName(), params.length); return Object.class; } if (!(params[index] instanceof Class)) { logger.warn(clazz.getSimpleName() + " not set the actual class on superclass generic parameter"); return Object.class; } return (Class) params[index]; } /** * ?CGLib??. */ public static Class<?> getProxyBeanOrgClass(Object instance) { Validate.notNull(instance, "Instance must not be null"); Class clazz = instance.getClass(); if ((clazz != null) && clazz.getName().contains(CGLIB_CLASS_SEPARATOR)) { Class<?> superClass = clazz.getSuperclass(); if ((superClass != null) && !Object.class.equals(superClass)) { return superClass; } } return clazz; } /** * ??checked exception?unchecked exception. */ public static RuntimeException convertReflectionExceptionToUnchecked(Exception e) { if ((e instanceof IllegalAccessException) || (e instanceof IllegalArgumentException) || (e instanceof NoSuchMethodException)) { return new IllegalArgumentException(e); } else if (e instanceof InvocationTargetException) { return new RuntimeException(((InvocationTargetException) e).getTargetException()); } else if (e instanceof RuntimeException) { return (RuntimeException) e; } return new RuntimeException("Unexpected Checked Exception.", e); } /** * ?? CGLIBjdk?? * * @param bean * @return */ public static boolean isProxyBean(Object bean) { boolean isProxy = false; Class<?> clazz = bean.getClass(); if ((clazz != null) && (clazz.getName().contains(CGLIB_CLASS_SEPARATOR) || bean instanceof Proxy)) { isProxy = true; } return isProxy; } /** * ??? */ public static String[] getFiledNames(Class<?> clazz) { Field[] fields = clazz.getDeclaredFields(); String[] fieldNames = new String[fields.length]; for (int i = 0; i < fields.length; i++) { fieldNames[i] = fields[i].getName(); } return fieldNames; } /** * ?fields */ public static Field[] getAllDeclaredFields(Class<?> type) { List<Field> fields = Lists.newArrayList(); Validate.notNull(type, "type can't be null"); for (Class<?> superClass = type; superClass != type; superClass = superClass.getSuperclass()) { Field[] curFields = superClass.getDeclaredFields(); for (Field f : curFields) { makeAccessible(f); fields.add(f); } } return fields.toArray(new Field[0]); } /** * ?????? */ public static String[] getStaticFiledNames(Class<?> clazz) { Field[] fields = clazz.getDeclaredFields(); String[] fieldNames = new String[fields.length]; for (int i = 0; i < fields.length; i++) { fieldNames[i] = fields[i].getName(); } return fieldNames; } /** * ???? * * @param clazz * @param methodName * @return */ public static Class<?> getMethodReturnTypeByName(Class<?> clazz, String methodName) { Validate.notNull(clazz, "calzz can't be null"); Validate.notBlank(methodName); Method[] methods = clazz.getDeclaredMethods(); for (Method method : methods) { if (method.getName().equals(methodName)) { return method.getReturnType(); } } return null; } /** * ?, ?DeclaredField, ?. * <p> * ?Object?, null. */ public static Field getAccessibleFieldByType(Class<?> type, final String fieldName) { Validate.notNull(type, "type can't be null"); Validate.notBlank(fieldName, "fieldName can't be blank"); Field field = null; for (Class<?> superClass = type; superClass != type; superClass = superClass.getSuperclass()) { try { field = superClass.getDeclaredField(fieldName); makeAccessible(field); break; } catch (NoSuchFieldException e) {// NOSONAR // Field??,? } } return field; } // ======================================================================================= /** * Getter. */ public static Object invokeGetterMethod(Object obj, String propertyName) { String getterMethodName = "get" + StringUtils.capitalize(propertyName); return invokeMethod(obj, getterMethodName, new Class[] {}, new Object[] {}); } /** * Setter.valueClass?Setter. */ public static void invokeSetterMethod(Object obj, String propertyName, Object value) { invokeSetterMethod(obj, propertyName, value, null); } /** * Setter. * * @param propertyType Setter,valueClass. */ public static void invokeSetterMethod(Object obj, String propertyName, Object value, Class<?> propertyType) { Class<?> type = propertyType != null ? propertyType : value.getClass(); String setterMethodName = "set" + StringUtils.capitalize(propertyName); invokeMethod(obj, setterMethodName, new Class[] { type }, new Object[] { value }); } /** * ??, Class?. , 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", "rawtypes" }) public static <T> Class<T> getSuperClassGenricType(final Class clazz) { return getSuperClassGenricType(clazz, 0); } /** * ??, Class?. , Object.class. * <p> * 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("rawtypes") 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: {}, Size of {}'s Parameterized Type: {}", index, clazz.getSimpleName(), params.length); return Object.class; } if (!(params[index] instanceof Class)) { logger.warn(clazz.getSimpleName() + " not set the actual class on superclass generic parameter"); return Object.class; } return (Class) params[index]; } }