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;
/**
* 反射工具類.
*
*/
public class ReflectionUtils {
static {
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);
}
/**
* 調用Getter方法.
*/
public static Object invokeGetterMethod(Object target, String propertyName) {
String getterMethodName = "get" + StringUtils.capitalize(propertyName);
return invokeMethod(target, getterMethodName, new Class[] {}, new Object[] {});
}
/**
* 調用Setter方法.使用value的Class來查找Setter方法.
*/
public static void invokeSetterMethod(Object target, String propertyName, Object value) {
invokeSetterMethod(target, propertyName, value, null);
}
/**
* 調用Setter方法.
*
* @param propertyType 用於查找Setter方法,爲空時使用value的Class替代.
*/
public static void invokeSetterMethod(Object target, String propertyName, Object value, Class<?> propertyType) {
Class<?> type = propertyType != null ? propertyType : value.getClass();
String setterMethodName = "set" + StringUtils.capitalize(propertyName);
invokeMethod(target, setterMethodName, new Class[] { type }, new Object[] { value });
}
/**
* 直接讀取對象屬性值, 無視private/protected修飾符, 不經過getter函數.
*/
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) {
e.printStackTrace();
}
return result;
}
/**
* 直接設置對象屬性值, 無視private/protected修飾符, 不經過setter函數.
*/
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) {
e.printStackTrace();
}
}
/**
* 直接調用對象方法, 無視private/protected修飾符.
*/
public static Object invokeMethod(final Object object, final String methodName, final Class<?>[] parameterTypes,
final Object[] parameters) {
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 (Exception e) {
throw convertReflectionExceptionToUnchecked(e);
}
}
/**
* 循環向上轉型, 獲取對象的DeclaredField.
*
* 如向上轉型到Object仍無法找到, 返回null.
*/
protected static Field getDeclaredField(final Object object, final String fieldName) {
if (object == null) {
return null;
}
if (StringUtils.isBlank(fieldName)) {
return null;
}
for (Class<?> superClass = object.getClass(); superClass != Object.class; superClass = superClass
.getSuperclass()) {
try {
return superClass.getDeclaredField(fieldName);
} catch (NoSuchFieldException e) {//NOSONAR
// Field不在當前類定義,繼續向上轉型
}
}
return null;
}
/**
* 強行設置Field可訪問.
*/
protected static void makeAccessible(final Field field) {
if (!Modifier.isPublic(field.getModifiers()) || !Modifier.isPublic(field.getDeclaringClass().getModifiers())) {
field.setAccessible(true);
}
}
/**
* 循環向上轉型, 獲取對象的DeclaredMethod.
*
* 如向上轉型到Object仍無法找到, 返回null.
*/
protected static Method getDeclaredMethod(Object object, String methodName, Class<?>[] parameterTypes) {
if (object == null) {
return null;
}
for (Class<?> superClass = object.getClass(); superClass != Object.class; superClass = superClass
.getSuperclass()) {
try {
return superClass.getDeclaredMethod(methodName, parameterTypes);
} catch (NoSuchMethodException e) {//NOSONAR
// Method不在當前類定義,繼續向上轉型
}
}
return null;
}
/**
* 通過反射, 獲得Class定義中聲明的父類的泛型參數的類型.
* 如無法找到, 返回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")
public static <T> Class<T> getSuperClassGenricType(final Class clazz) {
return getSuperClassGenricType(clazz, 0);
}
/**
* 通過反射, 獲得定義Class時聲明的父類的泛型參數的類型.
* 如無法找到, 返回Object.class.
*
* 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)) {
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];
}
/**
* 提取集合中的對象的屬性(通過getter函數), 組合成List.
*
* @param collection 來源集合.
* @param propertyName 要提取的屬性名.
*/
@SuppressWarnings("unchecked")
public static List convertElementPropertyToList(final Collection collection, final String propertyName) {
List list = new ArrayList();
try {
for (Object obj : collection) {
list.add(PropertyUtils.getProperty(obj, propertyName));
}
} catch (Exception e) {
throw convertReflectionExceptionToUnchecked(e);
}
return list;
}
/**
* 提取集合中的對象的屬性(通過getter函數), 組合成由分割符分隔的字符串.
*
* @param collection 來源集合.
* @param propertyName 要提取的屬性名.
* @param separator 分隔符.
*/
@SuppressWarnings("unchecked")
public static String convertElementPropertyToString(final Collection collection, final String propertyName,
final String separator) {
List list = convertElementPropertyToList(collection, propertyName);
return StringUtils.join(list, separator);
}
/**
* 轉換字符串到相應類型.
*
* @param value 待轉換的字符串
* @param toType 轉換目標類型
*/
@SuppressWarnings("unchecked")
public static <T> T convertStringToObject(String value, Class<T> toType) {
try {
return (T) ConvertUtils.convert(value, toType);
} catch (Exception e) {
throw convertReflectionExceptionToUnchecked(e);
}
}
/**
* 將反射時的checked exception轉換爲unchecked exception.
*/
public static RuntimeException convertReflectionExceptionToUnchecked(Exception e) {
return convertReflectionExceptionToUnchecked(null, e);
}
public static RuntimeException convertReflectionExceptionToUnchecked(String desc, Exception e) {
desc = (desc == null) ? "Unexpected Checked Exception." : desc;
if (e instanceof IllegalAccessException || e instanceof IllegalArgumentException
|| e instanceof NoSuchMethodException) {
return new IllegalArgumentException(desc, e);
} else if (e instanceof InvocationTargetException) {
return new RuntimeException(desc, ((InvocationTargetException) e).getTargetException());
} else if (e instanceof RuntimeException) {
return (RuntimeException) e;
}
return new RuntimeException(desc, e);
}
/**
* 得到新的對象
* @param <T>
* @param cls
* @return
*/
public static final <T> T getNewInstance(Class<T> cls) {
try {
return cls.newInstance();
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
}
return null;
}
}