From 102a40c46b9dbf7ae8254ea5504cfcaaebbe437e Mon Sep 17 00:00:00 2001 From: Looly Date: Tue, 26 Aug 2025 18:04:04 +0800 Subject: [PATCH] fix #ICUW8G --- .../hutool/v7/core/collection/CollUtil.java | 68 ++++++++++++++----- .../v7/core/collection/CollUtilTest.java | 19 +++++- 2 files changed, 69 insertions(+), 18 deletions(-) diff --git a/hutool-core/src/main/java/cn/hutool/v7/core/collection/CollUtil.java b/hutool-core/src/main/java/cn/hutool/v7/core/collection/CollUtil.java index c82d83028c..0692dfd2df 100644 --- a/hutool-core/src/main/java/cn/hutool/v7/core/collection/CollUtil.java +++ b/hutool-core/src/main/java/cn/hutool/v7/core/collection/CollUtil.java @@ -415,7 +415,7 @@ public class CollUtil { result.addAll(coll1); } result.removeAll(coll2); - } catch (UnsupportedOperationException e) { + } catch (final UnsupportedOperationException e) { // 针对 coll1 为只读集合的补偿 result = CollUtil.create(AbstractCollection.class); result.addAll(coll1); @@ -588,6 +588,7 @@ public class CollUtil { } // region ----- join + /** * 以 conjunction 为分隔符将集合转换为字符串 * @@ -819,6 +820,7 @@ public class CollUtil { } // region ----- sub + /** * 截取列表的部分 * @@ -969,6 +971,7 @@ public class CollUtil { } // region ----- remove + /** * 去掉集合中的多个元素，此方法直接修改原集合 * @@ -1133,6 +1136,7 @@ public class CollUtil { } // region ----- getFieldValues + /** * 获取给定Bean列表中指定字段名对应字段值的列表
* 列表元素支持Bean与Map @@ -1503,6 +1507,7 @@ public class CollUtil { } // region ----- addAll + /** * 将指定对象全部加入到集合中
* 提供的对象如果为集合类型，会自动转换为目标元素类型
@@ -1642,6 +1647,7 @@ public class CollUtil { // endregion // region ----- get + /** * 获取集合的第一个元素，如果集合为空（null或者空集合），返回{@code null} * @@ -1650,8 +1656,7 @@ public class CollUtil { * @return 第一个元素，为空返回{@code null} */ public static T getFirst(final Iterable iterable) { - if (iterable instanceof List) { - final List list = (List) iterable; + if (iterable instanceof final List list) { return CollUtil.isEmpty(list) ? null : list.get(0); } return IterUtil.getFirst(IterUtil.getIter(iterable)); @@ -1697,8 +1702,7 @@ public class CollUtil { */ public static T getFirstByField(final Iterable collection, final String fieldName, final Object fieldValue) { return getFirst(collection, t -> { - if (t instanceof Map) { - final Map map = (Map) t; + if (t instanceof final Map map) { final Object value = map.get(fieldName); return ObjUtil.equals(value, fieldValue); } @@ -1749,8 +1753,7 @@ public class CollUtil { return null; } - if (collection instanceof List) { - final List list = ((List) collection); + if (collection instanceof final List list) { return list.get(index); } else { return IterUtil.get(collection.iterator(), index); @@ -1773,8 +1776,7 @@ public class CollUtil { } final int size = collection.size(); final List result = new ArrayList<>(indexes.length); - if (collection instanceof List) { - final List list = ((List) collection); + if (collection instanceof final List list) { for (int index : indexes) { if (index < 0) { index += size; @@ -2033,6 +2035,7 @@ public class CollUtil { // endregion // region ----- group + /** * 分组，按照{@link Hash32}接口定义的hash算法，集合中的元素放入hash值对应的子列表中 * @@ -2167,29 +2170,61 @@ public class CollUtil { } /** - * 取最大值 + * 取最大值，情况如下： + *
    + *
  • 集合为空，返回null
    • + *
  • 集合元素全部为null，返回null
    • + *
  • 集合中如果有非null元素，始终返回非null
    • + *
* * @param 元素类型 * @param coll 集合 - * @return 最大值 + * @return 最大值，如果集合为空或者元素全部为null，返回null，否则始终返回非null元素 * @see Collections#max(Collection) * @since 4.6.5 */ public static > T max(final Collection coll) { - return isEmpty(coll) ? null : Collections.max(coll); + if (isEmpty(coll)) { + return null; + } + + final Iterator i = coll.iterator(); + T candidate = i.next(); + + while (i.hasNext()) { + candidate = CompareUtil.max(candidate, i.next()); + } + return candidate; } /** - * 取最小值 + * 取最小值，情况如下： + *
    + *
  • 集合为空，返回null
    • + *
  • 集合元素全部为null，返回null
    • + *
  • 集合中如果有非null元素，始终返回非null
    • + *
* * @param 元素类型 * @param coll 集合 - * @return 最小值 + * @return 最小值，如果集合为空或者元素全部为null，返回null，否则始终返回非null元素 * @see Collections#min(Collection) * @since 4.6.5 */ public static > T min(final Collection coll) { - return isEmpty(coll) ? null : Collections.min(coll); + if (isEmpty(coll)) { + return null; + } + + final Iterator i = coll.iterator(); + T candidate = i.next(); + + T next; + while (i.hasNext()) { + next = i.next(); + candidate = CompareUtil.compare(candidate, next, true) < 0 ? candidate : next; + } + return candidate; } /** @@ -2326,9 +2361,8 @@ public class CollUtil { return IterUtil.size((Iterable) object); } else if (object instanceof Iterator) { return IterUtil.size((Iterator) object); - } else if (object instanceof Enumeration) { + } else if (object instanceof final Enumeration it) { int total = 0; - final Enumeration it = (Enumeration) object; while (it.hasMoreElements()) { total++; it.nextElement(); diff --git a/hutool-core/src/test/java/cn/hutool/v7/core/collection/CollUtilTest.java b/hutool-core/src/test/java/cn/hutool/v7/core/collection/CollUtilTest.java index fa75b62faa..cfdd7ca482 100644 --- a/hutool-core/src/test/java/cn/hutool/v7/core/collection/CollUtilTest.java +++ b/hutool-core/src/test/java/cn/hutool/v7/core/collection/CollUtilTest.java @@ -1183,8 +1183,20 @@ public class CollUtilTest { @Test public void maxTest() { - final List list = Arrays.asList(1, 2, 3, 4, 5, 6); + List list = Arrays.asList(1, 2, 3, 4, 5, 6); assertEquals((Integer) 6, CollUtil.max(list)); + + list = Arrays.asList(1, 2, 3, null, 5, 6); + assertEquals((Integer) 6, CollUtil.max(list)); + } + + @Test + public void minTest() { + List list = Arrays.asList(1, 2, 3, 4, 5, 6); + assertEquals((Integer) 1, CollUtil.min(list)); + + list = Arrays.asList(1, 2, 3, null, 5, 6); + assertEquals((Integer) 1, CollUtil.min(list)); } @SuppressWarnings({"rawtypes", "unchecked"}) @@ -1196,6 +1208,11 @@ public class CollUtilTest { @Test public void minNullTest() { + Assertions.assertNull(CollUtil.min(null)); + } + + @Test + public void maxNullTest() { Assertions.assertNull(CollUtil.max(null)); }