java使用CollectionUtils工具类判断集合是否为空方式

CollectionUtils.isEmpty(a): true 

List<String> list = new ArrayList<>();
list.add("a");
list.add("b");
System.out.println(list); //list.size()==2　
CollectionUtils.isEmpty(list): false

CollectionUtils.isNotEmpty(a): false

List<String> list = new ArrayList<>();
list.add("a");
list.add("b");
System.out.println(list); //list.size()==2　　
CollectionUtils.isNotEmpty(list): true

public static boolean isNotEmpty(Collection coll) {
 return !isEmpty(coll);
}
public static boolean isEmpty(Collection coll) {
 return coll == null || coll.isEmpty();
}

org.springframework.util.CollectionUtils

//Collection 
public static boolean isEmpty(Collection collection)
{
return collection == null || collection.isEmpty();
}
//Map 
public static boolean isEmpty(Map map)
{
return map == null || map.isEmpty();
}