MAP集合與對象之間的互轉（示例代碼）

/**
 * 使用org.apache.commons.beanutils進行轉換
 */
class A {
 public static Object mapToObject(Map<String, Object> map, Class<?> beanClass)
   throws Exception {
  if (map == null)
   return null;
  Object obj = beanClass.newInstance();
  org.apache.commons.beanutils.BeanUtils.populate(obj, map);
  return obj;
 }

 public static Map<?, ?> objectToMap(Object obj) {
  if (obj == null)
   return null;
  return new org.apache.commons.beanutils.BeanMap(obj);
 }
}

/**
 * 使用Introspector進行轉換
 */
class B {
 public static Object mapToObject(Map<String, Object> map, Class<?> beanClass)
   throws Exception {
  if (map == null)
   return null;
  Object obj = beanClass.newInstance();
  BeanInfo beanInfo = Introspector.getBeanInfo(obj.getClass());
  PropertyDescriptor[] propertyDescriptors = beanInfo
    .getPropertyDescriptors();
  for (PropertyDescriptor property : propertyDescriptors) {
   Method setter = property.getWriteMethod();
   if (setter != null) {
    setter.invoke(obj, map.get(property.getName()));
   }
  }
  return obj;
 }

 public static Map<String, Object> objectToMap(Object obj) throws Exception {
  if (obj == null)
   return null;
  Map<String, Object> map = new HashMap<String, Object>();
  BeanInfo beanInfo = Introspector.getBeanInfo(obj.getClass());
  PropertyDescriptor[] propertyDescriptors = beanInfo
    .getPropertyDescriptors();
  for (PropertyDescriptor property : propertyDescriptors) {
   String key = property.getName();
   if (key.compareToIgnoreCase("class") == 0) {
    continue;
   }
   Method getter = property.getReadMethod();
   Object value = getter != null ? getter.invoke(obj) : null;
   map.put(key, value);
  }
  return map;
 }
}

/**
 * 使用reflect進行轉換
 */

class C {
 public static Object mapToObject(Map<String, Object> map, Class<?> beanClass)
   throws Exception {
  if (map == null)
   return null;
  Object obj = beanClass.newInstance();
  Field[] fields = obj.getClass().getDeclaredFields();
  for (Field field : fields) {
   int mod = field.getModifiers();
   if (Modifier.isStatic(mod) || Modifier.isFinal(mod)) {
    continue;
   }

   field.setAccessible(true);
   field.set(obj, map.get(field.getName()));

  }
  return obj;
 }

 public static Map<String, Object> objectToMap(Object obj) throws Exception {
  if (obj == null) {
   return null;
  }

  Map<String, Object> map = new HashMap<String, Object>();
  Field[] declaredFields = obj.getClass().getDeclaredFields();
  for (Field field : declaredFields) {
   field.setAccessible(true);
   map.put(field.getName(), field.get(obj));
  }
  return map;
 }

}