From a1f8a9e09345dea6455bf57c2b2dadceef45df8c Mon Sep 17 00:00:00 2001
From: youzipi <blake_12@qq.com>
Date: Mon, 13 Mar 2023 16:22:52 +0800
Subject: [PATCH] feat: CollUtil add groupByFunc

---
 .../cn/hutool/core/collection/CollUtil.java   | 14 +++++++-----
 .../hutool/core/collection/CollUtilTest.java  | 22 ++++++++++++++++++-
 2 files changed, 30 insertions(+), 6 deletions(-)

diff --git a/hutool-core/src/main/java/cn/hutool/core/collection/CollUtil.java b/hutool-core/src/main/java/cn/hutool/core/collection/CollUtil.java
index 3ac2129fd..a660dd112 100755
--- a/hutool-core/src/main/java/cn/hutool/core/collection/CollUtil.java
+++ b/hutool-core/src/main/java/cn/hutool/core/collection/CollUtil.java
@@ -2023,8 +2023,12 @@ public class CollUtil {
 	 * @return 分组列表
 	 */
 	public static <T> List<List<T>> groupByField(final Collection<T> collection, final String fieldName) {
+		return groupByFunc(collection, t -> BeanUtil.getFieldValue(t, fieldName));
+	}
+
+	public static <T,D> List<List<T>> groupByFunc(final Collection<T> collection, final Function<T,D> getter) {
 		return group(collection, new Hash32<T>() {
-			private final List<Object> fieldNameList = new ArrayList<>();
+			private final List<Object> hashValList = new ArrayList<>();
 
 			@Override
 			public int hash32(final T t) {
@@ -2032,11 +2036,11 @@ public class CollUtil {
 					// 非Bean放在同一子分组中
 					return 0;
 				}
-				final Object value = FieldUtil.getFieldValue(t, fieldName);
-				final int hash = fieldNameList.indexOf(value);
+				final D value = getter.apply(t);
+				final int hash = hashValList.indexOf(value);
 				if (hash < 0) {
-					fieldNameList.add(value);
-					return fieldNameList.size() - 1;
+					hashValList.add(value);
+					return hashValList.size() - 1;
 				} else {
 					return hash;
 				}
diff --git a/hutool-core/src/test/java/cn/hutool/core/collection/CollUtilTest.java b/hutool-core/src/test/java/cn/hutool/core/collection/CollUtilTest.java
index fc5f4a2b4..acb7cf236 100755
--- a/hutool-core/src/test/java/cn/hutool/core/collection/CollUtilTest.java
+++ b/hutool-core/src/test/java/cn/hutool/core/collection/CollUtilTest.java
@@ -427,6 +427,26 @@ public class CollUtilTest {
 		Assert.assertEquals("李四", groupByField.get(1).get(0).getName());
 	}
 
+	@Test
+	public void groupByFuncTest() {
+		final List<TestBean> list = ListUtil.of(new TestBean("张三", 12), new TestBean("李四", 13), new TestBean("王五", 12));
+		final List<List<TestBean>> groupByField = CollUtil.groupByFunc(list, TestBean::getAge);
+		Assert.assertEquals("张三", groupByField.get(0).get(0).getName());
+		Assert.assertEquals("王五", groupByField.get(0).get(1).getName());
+
+		Assert.assertEquals("李四", groupByField.get(1).get(0).getName());
+	}
+
+	@Test
+	public void groupByFunc2Test() {
+		final List<TestBean> list = ListUtil.of(new TestBean("张三", 12), new TestBean("李四", 13), new TestBean("王五", 12));
+		final List<List<TestBean>> groupByField = CollUtil.groupByFunc(list, a -> a.getAge() > 12);
+		Assert.assertEquals("张三", groupByField.get(0).get(0).getName());
+		Assert.assertEquals("王五", groupByField.get(0).get(1).getName());
+
+		Assert.assertEquals("李四", groupByField.get(1).get(0).getName());
+	}
+
 	@Test
 	public void sortByPropertyTest() {
 		final List<TestBean> list = ListUtil.of(
@@ -854,7 +874,7 @@ public class CollUtilTest {
 
 		final List<Long> result = CollUtil.subtractToList(list1, list2);
 		Assert.assertEquals(1, result.size());
-		Assert.assertEquals(1L, (long)result.get(0));
+		Assert.assertEquals(1L, (long) result.get(0));
 	}
 
 	@Test