java将对象列表中的某个属性转换成List或Map

/**
 * @Description 对象属性操作工具类
 * @Package com.viathink.msswms.sample.utils.PropertiesUtils.java
 * @author LiuJunGuang
 * @date 2012-5-11 下午1:54:08
 * @version V1.0
 */
public class PropertiesUtils {

	/**
	 * 根据对象列表和对象的某个属性返回属性的List集合
	 * 
	 * @param objList
	 *            对象列表
	 * @param propertyName
	 *            要操作的属性名称
	 * @return 
	 * 	指定属性的List集合;
	 * 	如果objList为null或者size等于0抛出 IllegalArgumentException异常;
	 *  如果propertyName为null抛出 IllegalArgumentException异常
	 * 
* @throws NoSuchMethodException * @throws InvocationTargetException */ public static List getPropertyList(List objList, String propertyName) throws IllegalAccessException, InvocationTargetException, NoSuchMethodException { if (objList == null || objList.size() == 0) throw new IllegalArgumentException("No objList specified"); if (propertyName == null || "".equals(propertyName)) { throw new IllegalArgumentException("No propertyName specified for bean class '" + objList.get(0).getClass() + "'"); } PropertyUtilsBean p = new PropertyUtilsBean(); List propList = new LinkedList(); for (int i = 0; i < objList.size(); i++) { T obj = objList.get(i); propList.add(p.getProperty(obj, propertyName)); } return propList; } /** * 将List列表中的对象的某个属性封装成一个Map对象,key值是属性名,value值是对象列表中对象属性值的列表 * * @param objList * 对象列表 * @param propertyName * 属性名称,可以是一个或者多个 * @return 返回封装了属性名称和属性值列表的Map对象,如果参数非法则抛出异常信息 * @throws IllegalAccessException * @throws InvocationTargetException * @throws NoSuchMethodException */ public static Map> getPropertiesMap(List objList, String... propertyName) throws IllegalAccessException, InvocationTargetException, NoSuchMethodException { if (objList == null || objList.size() == 0) throw new IllegalArgumentException("No objList specified"); if (propertyName == null || propertyName.length == 0) { throw new IllegalArgumentException("No propertyName specified for bean class '" + objList.get(0).getClass() + "'"); } Map> maps = new HashMap>(); for (int i = 0; i < propertyName.length; i++) { maps.put(propertyName[i], getPropertyList(objList, propertyName[i])); } return maps; } }用到BeanUtils工具包

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