public class CollectionUtils
extends java.lang.Object
| 构造器和说明 |
|---|
CollectionUtils() |
| 限定符和类型 | 方法和说明 |
|---|---|
static <L,R,V> PairMap<L,R,java.util.List<V>> |
groupingBy(java.util.Collection<V> collection,
java.util.function.Function<? super V,? extends L> leftMapper,
java.util.function.Function<? super V,? extends R> rightMapper)
根据两个属性为条件对指定集合进行分组.
|
static boolean |
isEmpty(java.util.Collection<?> collection)
检测集合是否为
null或长度为0 |
static boolean |
isNotEmpty(java.util.Collection<?> collection)
检测集合是否不为
null或长度大于0 |
public static boolean isEmpty(java.util.Collection<?> collection)
null或长度为0collection - 被检测集合null或长度为0则返回true,否则返回false.public static boolean isNotEmpty(java.util.Collection<?> collection)
null或长度大于0collection - 被检测集合null或长度大于0则返回true,否则返回false.public static <L,R,V> PairMap<L,R,java.util.List<V>> groupingBy(java.util.Collection<V> collection, java.util.function.Function<? super V,? extends L> leftMapper, java.util.function.Function<? super V,? extends R> rightMapper)
常用于模板分组缓存备用
L - 属性一的类型R - 属性二的类型V - 集合元素的类型collection - 指定集合leftMapper - 属性一rightMapper - 属性二