java反射工具类

import java.lang.reflect.Field;
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.List;

import org.apache.commons.beanutils.PropertyUtils;
import org.apache.commons.lang.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.ocj.pojo.ProductBean;
/**
 * 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.
 * 
 * @author luochang
 */
public class ReflectionUtils {

	private static Logger logger = LoggerFactory.getLogger(ReflectionUtils.class);

	private ReflectionUtils() {
	}

	/**
	 * 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("不可能抛出的异常{}", e.getMessage());
		}
		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("不可能抛出的异常:{}", e.getMessage());
		}
	}

	/**
	 * 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");
		return getDeclaredField(object.getClass(), fieldName);
	}

	/**
	 * 循环向上转型,获取类的DeclaredField.
	 */
	@SuppressWarnings("unchecked")
	protected static Field getDeclaredField(final Class clazz, final String fieldName) {
//		Assert.notNull(clazz, "clazz不能为空");
//		Assert.hasText(fieldName, "fieldName");
		for (Class superClass = clazz; 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,获取类的所有的DeclaredField,无视修饰符
	 */
	protected static List<String> getDeclaredField(final Class clazz) {
		List<String>fields=new ArrayList<String>();
		if (clazz!=Object.class) {
			Field [] arr =clazz.getDeclaredFields();
			if (arr!=null && arr.length>0) {
				for (int i = 0; i < arr.length; i++) {
					makeAccessible(arr[i]);
					fields.add(arr[i].getName());
				}
			}
		}
		return fields;
	}
	
	

	/**
	 * 强制转换fileld可访问.
	 */
	protected static void makeAccessible(final Field field) {
		if (!Modifier.isPublic(field.getModifiers()) || !Modifier.isPublic(field.getDeclaringClass().getModifiers())) {
			field.setAccessible(true);
		}
	}

	/**
	 * 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>
	 * 
	 * @param clazz
	 *            The class to introspect
	 * @return the first generic declaration, or Object.class if cannot be
	 *         determined
	 */
	@SuppressWarnings("unchecked")
	public static Class 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,组合成List.
	 * 
	 * @param collection
	 *            来源集合.
	 * @param propertityName
	 *            要提取的属性名.
	 */
	@SuppressWarnings("unchecked")
	public static List fetchElementPropertyToList(final Collection collection, final String propertyName) throws Exception {

		List list = new ArrayList();

		for (Object obj : collection) {
			list.add(PropertyUtils.getProperty(obj, propertyName));
		}

		return list;
	}

	/**
	 * 提取集合中的对象的属性,组合成由分割符分隔的字符串.
	 * 
	 * @param collection
	 *            来源集合.
	 * @param propertityName
	 *            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) throws Exception {
		List list = fetchElementPropertyToList(collection, propertyName);
		return StringUtils.join(list.toArray(), separator);
	}
	
	public static void main(String[] args) throws ClassNotFoundException {
		List<String > list=ReflectionUtils.getDeclaredField(ProductBean.class);
//		List<String > list=ReflectionUtils.getDeclaredField(Class.forName("com.ocj.pojo.ProductBean"));
		for (String string : list) {
			System.out.println(string);
		}
	}
}

 

import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.List;

/**
 * 泛型工具类
 * 获取Class<?>实例后，如果要得到 T 实例，直接T t = (T)c.newInstance()即可得到 
 * @author luochang
 */
public class GenericsUtils {
	/**
	 * 通过反射,获得指定类的父类的泛型参数的实际类型. 如BuyerServiceBean extends DaoSupport<Buyer>
	 * 
	 * @param clazz
	 *            clazz 需要反射的类,该类必须继承范型父类
	 * @param index
	 *            泛型参数所在索引,从0开始.
	 * @return 范型参数的实际类型, 如果没有实现ParameterizedType接口，即不支持泛型，所以直接返回
	 *         <code>Object.class</code>
	 */
	@SuppressWarnings("unchecked")
	public static Class getSuperClassGenricType(Class clazz, int index) {
		Type genType = clazz.getGenericSuperclass();// 得到泛型父类
		// 如果没有实现ParameterizedType接口，即不支持泛型，直接返回Object.class
		if (!(genType instanceof ParameterizedType)) {
			return Object.class;
		}
		// 返回表示此类型实际类型参数的Type对象的数组,数组里放的都是对应类型的Class, 如BuyerServiceBean extends
		// DaoSupport<Buyer,Contact>就返回Buyer和Contact类型
		Type[] params = ((ParameterizedType) genType).getActualTypeArguments();
		if (index >= params.length || index < 0) {
			throw new RuntimeException("你输入的索引"
					+ (index < 0 ? "不能小于0" : "超出了参数的总数"));
		}
		if (!(params[index] instanceof Class)) {
			return Object.class;
		}
		return (Class) params[index];
	}

	/**
	 * 通过反射,获得指定类的父类的第一个泛型参数的实际类型. 如BuyerServiceBean extends DaoSupport<Buyer>
	 * 
	 * @param clazz
	 *            clazz 需要反射的类,该类必须继承泛型父类
	 * @return 泛型参数的实际类型, 如果没有实现ParameterizedType接口，即不支持泛型，所以直接返回
	 *         <code>Object.class</code>
	 */
	@SuppressWarnings("unchecked")
	public static Class getSuperClassGenricType(Class clazz) {
		return getSuperClassGenricType(clazz, 0);
	}

	/**
	 * 通过反射,获得方法返回值泛型参数的实际类型. 如: public Map<String, Buyer> getNames(){}
	 * 
	 * @param Method
	 *            method 方法
	 * @param int index 泛型参数所在索引,从0开始.
	 * @return 泛型参数的实际类型, 如果没有实现ParameterizedType接口，即不支持泛型，所以直接返回
	 *         <code>Object.class</code>
	 */
	@SuppressWarnings("unchecked")
	public static Class getMethodGenericReturnType(Method method, int index) {
		Type returnType = method.getGenericReturnType();
		if (returnType instanceof ParameterizedType) {
			ParameterizedType type = (ParameterizedType) returnType;
			Type[] typeArguments = type.getActualTypeArguments();
			if (index >= typeArguments.length || index < 0) {
				throw new RuntimeException("你输入的索引"
						+ (index < 0 ? "不能小于0" : "超出了参数的总数"));
			}
			return (Class) typeArguments[index];
		}
		return Object.class;
	}

	/**
	 * 通过反射,获得方法返回值第一个泛型参数的实际类型. 如: public Map<String, Buyer> getNames(){}
	 * 
	 * @param Method
	 *            method 方法
	 * @return 泛型参数的实际类型, 如果没有实现ParameterizedType接口，即不支持泛型，所以直接返回
	 *         <code>Object.class</code>
	 */
	@SuppressWarnings("unchecked")
	public static Class getMethodGenericReturnType(Method method) {
		return getMethodGenericReturnType(method, 0);
	}

	/**
	 * 通过反射,获得方法输入参数第index个输入参数的所有泛型参数的实际类型. 如: public void add(Map<String,
	 * Buyer> maps, List<String> names){}
	 * 
	 * @param Method
	 *            method 方法
	 * @param int index 第几个输入参数
	 * @return 输入参数的泛型参数的实际类型集合, 如果没有实现ParameterizedType接口，即不支持泛型，所以直接返回空集合
	 */
	@SuppressWarnings("unchecked")
	public static List<Class> getMethodGenericParameterTypes(Method method,
			int index) {
		List<Class> results = new ArrayList<Class>();
		Type[] genericParameterTypes = method.getGenericParameterTypes();
		if (index >= genericParameterTypes.length || index < 0) {
			throw new RuntimeException("你输入的索引"
					+ (index < 0 ? "不能小于0" : "超出了参数的总数"));
		}
		Type genericParameterType = genericParameterTypes[index];
		if (genericParameterType instanceof ParameterizedType) {
			ParameterizedType aType = (ParameterizedType) genericParameterType;
			Type[] parameterArgTypes = aType.getActualTypeArguments();
			for (Type parameterArgType : parameterArgTypes) {
				Class parameterArgClass = (Class) parameterArgType;
				results.add(parameterArgClass);
			}
			return results;
		}
		return results;
	}

	/**
	 * 通过反射,获得方法输入参数第一个输入参数的所有泛型参数的实际类型. 如: public void add(Map<String, Buyer>
	 * maps, List<String> names){}
	 * 
	 * @param Method
	 *            method 方法
	 * @return 输入参数的泛型参数的实际类型集合, 如果没有实现ParameterizedType接口，即不支持泛型，所以直接返回空集合
	 */
	@SuppressWarnings("unchecked")
	public static List<Class> getMethodGenericParameterTypes(Method method) {
		return getMethodGenericParameterTypes(method, 0);
	}

	/**
	 * 通过反射,获得Field泛型参数的实际类型. 如: public Map<String, Buyer> names;
	 * 
	 * @param Field
	 *            field 字段
	 * @param int index 泛型参数所在索引,从0开始.
	 * @return 泛型参数的实际类型, 如果没有实现ParameterizedType接口，即不支持泛型，所以直接返回
	 *         <code>Object.class</code>
	 */
	@SuppressWarnings("unchecked")
	public static Class getFieldGenericType(Field field, int index) {
		Type genericFieldType = field.getGenericType();

		if (genericFieldType instanceof ParameterizedType) {
			ParameterizedType aType = (ParameterizedType) genericFieldType;
			Type[] fieldArgTypes = aType.getActualTypeArguments();
			if (index >= fieldArgTypes.length || index < 0) {
				throw new RuntimeException("你输入的索引"
						+ (index < 0 ? "不能小于0" : "超出了参数的总数"));
			}
			return (Class) fieldArgTypes[index];
		}
		return Object.class;
	}

	/**
	 * 通过反射,获得Field泛型参数的实际类型. 如: public Map<String, Buyer> names;
	 * 
	 * @param Field
	 *            field 字段
	 * @param int index 泛型参数所在索引,从0开始.
	 * @return 泛型参数的实际类型, 如果没有实现ParameterizedType接口，即不支持泛型，所以直接返回
	 *         <code>Object.class</code>
	 */
	@SuppressWarnings("unchecked")
	public static Class getFieldGenericType(Field field) {
		return getFieldGenericType(field, 0);
	}
}