package com.norteksoft.product.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.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.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
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.
*
*/
public class ReflectionUtils {
private static Log logger = LogFactory.getLog(ReflectionUtils.class);
/**
* 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(e.getMessage(), e);
}
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(e.getMessage(), e);
}
}
/**
* 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) 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) {
logger.error(e.getMessage(), e);
}
return null;
}
/**
* 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");
Assert.hasText(fieldName, "fieldName");
for (Class<?> superClass = object.getClass(); 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;
}
/**
* 循环向上转型,获取对象的DeclaredField.
*/
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.
*/
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) {
// 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.
* 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[index] instanceof Class)) {
logger.warn(clazz.getSimpleName() + " not set the actual class on superclass generic parameter");
return Object.class;
}
return (Class) params[index];
}
/**
* 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 fetchElementPropertyToList(final Collection collection, final String propertyName) {
List list = new ArrayList();
try {
for (Object obj : collection) {
list.add(PropertyUtils.getProperty(obj, propertyName));
}
} catch (Exception e) {
convertToUncheckedException(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 fetchElementPropertyToString(final Collection collection, final String propertyName,
final String separator) {
List list = fetchElementPropertyToList(collection, propertyName);
return StringUtils.join(list, separator);
}
/**
* 转换字符串类型到clazz的property类型的值.
*
* @param value 待转换的字符串
* @param clazz 提供类型信息的Class
* @param propertyName 提供类型信息的Class的属性.
*/
public static Object convertValue(Object value, Class<?> toType) {
try {
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);
return ConvertUtils.convert(value, toType);
} catch (Exception e) {
throw convertToUncheckedException(e);
}
}
/**
* 将反射时的checked exception转换为unchecked exception.
*/
public static IllegalArgumentException convertToUncheckedException(Exception e) {
if (e instanceof IllegalAccessException || e instanceof IllegalArgumentException
|| e instanceof NoSuchMethodException)
return new IllegalArgumentException("Refelction Exception.", e);
else
return new IllegalArgumentException(e);
}
}