Java之工具类：判断对象是否为空或null

 import java.lang.reflect.Array;
 import java.util.Collection;
 import java.util.Map;

 /**
  * 判断对象是否为空或null
  */
 public class ObjectUtils {

     public static boolean isNull(Object obj) {
         return obj == null;
     }

     public static boolean isNotNull(Object obj) {
         return !isNull(obj);
     }

     public static boolean isEmpty(Object obj) {
         if (obj == null) return true;
         else if (obj instanceof CharSequence) return ((CharSequence) obj).length() == 0;
         else if (obj instanceof Collection) return ((Collection) obj).isEmpty();
         else if (obj instanceof Map) return ((Map) obj).isEmpty();
         else if (obj.getClass().isArray()) return Array.getLength(obj) == 0;

         return false;
     }

     public static boolean isNotEmpty(Object obj) {
         return !isEmpty(obj);
     }
 }