import java.beans.BeanInfo;  
import java.beans.Introspector;  
import java.beans.PropertyDescriptor;  
import java.lang.reflect.Method;  
import java.util.HashMap;  
import java.util.Map;  
 
import org.apache.commons.beanutils.BeanUtils;  

/** 
 *  Map與Bean互轉
 * 
 * 
* 當把Person類作為BeanUtilTest的內部類時，程式出錯<br> 
* java.lang.NoSuchMethodException: Property '**' has no setter method<br> 
* 本質：內部類 和 單獨檔案中的類的區別 <br> 
* BeanUtils.populate方法的限制：<br> 
* The class must be public, and provide a public constructor that accepts no arguments. <br> 
* This allows tools and applications to dynamically create new instances of your bean, <br> 
* without necessarily knowing what Java class name will be used ahead of time 
*/  
public class MapBeanConvertUtil {  
 
   /**
    * <p class="detail">
    * 功能：Map --> Bean 2: 利用org.apache.commons.beanutils 工具類實現 Map --> Bean  
    * 	推薦使用
    * </p>
    * @author wuxw
    * @param map
    * @param obj 
    * @throws
    */
   public static void transMap2Bean(Map<String, Object> map, Object obj) {  
       if (map == null || obj == null) {  
           return;  
       }  
       try {  
           BeanUtils.populate(obj, map);  
       } catch (Exception e) {  
           System.out.println("transMap2Bean2 Error " + e);  
       }  
   }  
 
   // Map --> Bean 1: 利用Introspector,PropertyDescriptor實現 Map --> Bean  
   public static void transMap2Bean2(Map<String, Object> map, Object obj) {  
 
       try {  
           BeanInfo beanInfo = Introspector.getBeanInfo(obj.getClass());  
           PropertyDescriptor[] propertyDescriptors = beanInfo.getPropertyDescriptors();  
 
           for (PropertyDescriptor property : propertyDescriptors) {  
               String key = property.getName();  
 
               if (map.containsKey(key)) {  
                   Object value = map.get(key);  
                   // 得到property對應的setter方法  
                   Method setter = property.getWriteMethod();  
                   setter.invoke(obj, value);  
               }  
 
           }  
 
       } catch (Exception e) {  
           System.out.println("transMap2Bean Error " + e);  
       }  
 
       return;  
 
   }  
   
   /**
    * <p class="detail">
    * 功能： Map --> Bean 1: 利用Introspector,PropertyDescriptor實現 Map --> Bean 
    * 	固定hibernateBean型別轉換:  user_name 轉 userName ,注意嚴格驗證引數 
    * 	
    * </p>
    * @author wuxw
    * @param map
    * @param obj 
    * @throws
    */
   public static void transMap2HiberanteBean(Map<String, Object> map, Object obj) {  
 
       try {  
           BeanInfo beanInfo = Introspector.getBeanInfo(obj.getClass());  
           PropertyDescriptor[] propertyDescriptors = beanInfo.getPropertyDescriptors();  
 
           for (PropertyDescriptor property : propertyDescriptors) {  
               String key = property.getName();  
               //將key中大寫字元轉為_大寫
               key = underscoreName(key);
               
               if (map.containsKey(key)) {  
                   Object value = map.get(key);  
                   // 得到property對應的setter方法  
                   Method setter = property.getWriteMethod();  
                   setter.invoke(obj, value);  
               }  
 
           }  
 
       } catch (Exception e) {  
           System.out.println("transMap2Bean Error " + e);  
       }  
 
       return;  
 
   } 
   
   
   // Bean --> Map 1: 利用Introspector和PropertyDescriptor 將Bean --> Map  
   public static Map<String, Object> transBean2Map(Object obj) {  
 
       if(obj == null){  
           return null;  
       }          
       Map<String, Object> map = new HashMap<String, Object>();  
       try {  
           BeanInfo beanInfo = Introspector.getBeanInfo(obj.getClass());  
           PropertyDescriptor[] propertyDescriptors = beanInfo.getPropertyDescriptors();  
           for (PropertyDescriptor property : propertyDescriptors) {  
               String key = property.getName();  
               // 過濾class屬性  
               if (!key.equals("class")) {  
                   // 得到property對應的getter方法  
                   Method getter = property.getReadMethod();  
                   Object value = getter.invoke(obj);  
 
                   map.put(key, value);  
               }  
 
           }  
       } catch (Exception e) {  
           System.out.println("transBean2Map Error " + e);  
       }  
 
       return map;  
 
   }  
   
   /**
    * <p class="detail">
    * 功能：將大寫轉為下劃線,且小寫 如: userName > user_name
    * </p>
    * @author wuxw
    * @param name
    * @return 
    * @throws
    */
   static String underscoreName(String name)  
   {  
     StringBuilder result = new StringBuilder();  
     if ((name != null) && (name.length() > 0)) {  
       result.append(name.substring(0, 1).toLowerCase());  
       for (int i = 1; i < name.length(); ++i) {  
         String s = name.substring(i, i + 1);  
         if (s.equals(s.toUpperCase())) {  
           result.append("_");  
           result.append(s.toLowerCase());  
         }  
         else {  
           result.append(s);  
         }  
       }  
     }  
     return result.toString();  
   }
}