CollUtil添加解构collection内部的多个collection为单个list的方法

hutool-core/src/main/java/org/dromara/hutool/core/collection/CollUtil.java

@@ -34,6 +34,7 @@ import org.dromara.hutool.core.map.MapUtil;
 import org.dromara.hutool.core.reflect.ConstructorUtil;
 import org.dromara.hutool.core.reflect.FieldUtil;
 import org.dromara.hutool.core.reflect.TypeUtil;
+import org.dromara.hutool.core.stream.EasyStream;
 import org.dromara.hutool.core.stream.StreamUtil;
 import org.dromara.hutool.core.text.StrUtil;
 import org.dromara.hutool.core.text.split.SplitUtil;
@@ -1554,7 +1555,7 @@ public class CollUtil {
 			// String按照逗号分隔的列表对待
 			final String arrayStr = StrUtil.unWrap((CharSequence) value, '[', ']');
 			iter = SplitUtil.splitTrim(arrayStr, StrUtil.COMMA).iterator();
-		} else if(value instanceof Map && BeanUtil.isWritableBean(TypeUtil.getClass(elementType))){
+		} else if (value instanceof Map && BeanUtil.isWritableBean(TypeUtil.getClass(elementType))) {
 			//https://github.com/dromara/hutool/issues/3139
 			// 如果值为Map，而目标为一个Bean，则Map应整体转换为Bean，而非拆分成Entry转换
 			iter = new ArrayIter<>(new Object[]{value});
@@ -2354,4 +2355,48 @@ public class CollUtil {
 		}
 		return collection.stream().allMatch(predicate);
 	}
+
+	/**
+	 * 结构多层集合
+	 * 例如：List<List<List<String>>> 解构成 List<String>
+	 *
+	 * @param collection 需要解构的集合
+	 * @return 解构后的集合
+	 */
+	public static List<Object> flat(Collection<?> collection) {
+		return flat(collection, true);
+	}
+
+	/**
+	 * 结构多层集合
+	 * 例如：List<List<List<String>>> 解构成 List<String>
+	 * <p>
+	 * skipNull的作用是当集合里面有个值为空，当为true是解构后的集合里面没有null值，如果为false则会在解构后的集合里面有努力了。
+	 *
+	 * @param collection 需要结构的集合
+	 * @param skipNull   是否跳过空的值
+	 * @return 解构后的集合
+	 */
+	@SuppressWarnings({"unchecked"})
+	public static List<Object> flat(Collection<?> collection, boolean skipNull) {
+		LinkedList queue = EasyStream.of(collection)
+			.collect(Collectors.toCollection(LinkedList::new));
+
+		List<Object> result = new ArrayList<>();
+
+		while (!queue.isEmpty()) {
+			Object t = queue.removeFirst();
+
+			if (skipNull && t == null) {
+				continue;
+			}
+
+			if (t instanceof Collection) {
+				queue.addAll((Collection<?>) t);
+			} else {
+				result.add(t);
+			}
+		}
+		return result;
+	}
 }

hutool-core/src/main/java/org/dromara/hutool/core/collection/ListUtil.java

@@ -27,7 +27,6 @@ import org.dromara.hutool.core.util.ObjUtil;
 import java.util.*;
 import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.function.Consumer;
-import java.util.function.Function;
 import java.util.function.Predicate;
 
 /**
@@ -749,46 +748,4 @@ public class ListUtil {
 		}
 		return resList;
 	}
-
-	/**
-	 * 解构list里面的list为单个list
-	 *
-	 * @param list 传入的list集合
-	 * @param <T>  返回的元素类型
-	 * @return 解构后的list集合
-	 */
-	public static <T> List<T> flatList(List<?> list) {
-		return flatList(list, Function.identity());
-	}
-
-	/**
-	 * 解构list里面的list，并可以对每个元素操作
-	 *
-	 * @param list      传入的list集合
-	 * @param operation 对每个元素进行操作
-	 * @param <T>       返回的元素类型
-	 * @param <O>       最内侧的元素类型
-	 * @return 解构后的list集合
-	 */
-	@SuppressWarnings("all")
-	public static <T, O> List<T> flatList(List<?> list, Function<O, T> operation) {
-		List<T> result = new ArrayList<>();
-
-		if (list == null || list.isEmpty()) {
-			return result;
-		}
-
-		if (list.get(0) instanceof List) {
-			for (List<?> subList : (List<List<?>>) list) {
-				result.addAll(flatList(subList, operation));
-			}
-		} else {
-			for (Object item : list) {
-				result.add(operation.apply((O) item));
-			}
-		}
-
-		return result;
-	}
-
 }

hutool-core/src/test/java/org/dromara/hutool/core/collection/CollUtilTest.java

@@ -3,6 +3,7 @@ package org.dromara.hutool.core.collection;
 import org.dromara.hutool.core.collection.iter.IterUtil;
 import org.dromara.hutool.core.collection.set.SetUtil;
 import org.dromara.hutool.core.comparator.CompareUtil;
+import org.dromara.hutool.core.convert.Convert;
 import org.dromara.hutool.core.date.DateUtil;
 import org.dromara.hutool.core.lang.Console;
 import org.dromara.hutool.core.map.Dict;
@@ -460,9 +461,9 @@ public class CollUtilTest {
 	@Test
 	public void sortByPropertyTest() {
 		final List<TestBean> list = ListUtil.of(
-				new TestBean("张三", 12, DateUtil.parse("2018-05-01")), //
-				new TestBean("李四", 13, DateUtil.parse("2018-03-01")), //
-				new TestBean("王五", 12, DateUtil.parse("2018-04-01"))//
+			new TestBean("张三", 12, DateUtil.parse("2018-05-01")), //
+			new TestBean("李四", 13, DateUtil.parse("2018-03-01")), //
+			new TestBean("王五", 12, DateUtil.parse("2018-04-01"))//
 		);
 
 		CollUtil.sortByProperty(list, "createTime");
@@ -474,9 +475,9 @@ public class CollUtilTest {
 	@Test
 	public void sortByPropertyTest2() {
 		final List<TestBean> list = ListUtil.of(
-				new TestBean("张三", 0, DateUtil.parse("2018-05-01")), //
-				new TestBean("李四", -12, DateUtil.parse("2018-03-01")), //
-				new TestBean("王五", 23, DateUtil.parse("2018-04-01"))//
+			new TestBean("张三", 0, DateUtil.parse("2018-05-01")), //
+			new TestBean("李四", -12, DateUtil.parse("2018-03-01")), //
+			new TestBean("王五", 23, DateUtil.parse("2018-04-01"))//
 		);
 
 		CollUtil.sortByProperty(list, "age");
@@ -488,8 +489,8 @@ public class CollUtilTest {
 	@Test
 	public void fieldValueMapTest() {
 		final List<TestBean> list = ListUtil.of(new TestBean("张三", 12, DateUtil.parse("2018-05-01")), //
-				new TestBean("李四", 13, DateUtil.parse("2018-03-01")), //
-				new TestBean("王五", 12, DateUtil.parse("2018-04-01"))//
+			new TestBean("李四", 13, DateUtil.parse("2018-03-01")), //
+			new TestBean("王五", 12, DateUtil.parse("2018-04-01"))//
 		);
 
 		final Map<String, TestBean> map = CollUtil.fieldValueMap(list, "name");
@@ -501,8 +502,8 @@ public class CollUtilTest {
 	@Test
 	public void fieldValueAsMapTest() {
 		final List<TestBean> list = ListUtil.of(new TestBean("张三", 12, DateUtil.parse("2018-05-01")), //
-				new TestBean("李四", 13, DateUtil.parse("2018-03-01")), //
-				new TestBean("王五", 14, DateUtil.parse("2018-04-01"))//
+			new TestBean("李四", 13, DateUtil.parse("2018-03-01")), //
+			new TestBean("王五", 14, DateUtil.parse("2018-04-01"))//
 		);
 
 		final Map<String, Integer> map = CollUtil.fieldValueAsMap(list, "name", "age");
@@ -669,7 +670,7 @@ public class CollUtilTest {
 
 	@Test
 	public void subInput1PositiveNegativePositiveOutputArrayIndexOutOfBoundsException() {
-		Assertions.assertThrows(IndexOutOfBoundsException.class, ()->{
+		Assertions.assertThrows(IndexOutOfBoundsException.class, () -> {
 			// Arrange
 			final List<Integer> list = new ArrayList<>();
 			list.add(null);
@@ -821,8 +822,8 @@ public class CollUtilTest {
 		oldMap.put("c", "134");
 
 		final Map<String, Long> map = IterUtil.toMap(oldMap.entrySet(),
-				Map.Entry::getKey,
-				entry -> Long.parseLong(entry.getValue()));
+			Map.Entry::getKey,
+			entry -> Long.parseLong(entry.getValue()));
 
 		Assertions.assertEquals(1L, (long) map.get("a"));
 		Assertions.assertEquals(12L, (long) map.get("b"));
@@ -900,12 +901,12 @@ public class CollUtilTest {
 	public void setValueByMapTest() {
 		// https://gitee.com/dromara/hutool/pulls/482
 		final List<Person> people = Arrays.asList(
-				new Person("aa", 12, "man", 1),
-				new Person("bb", 13, "woman", 2),
-				new Person("cc", 14, "man", 3),
-				new Person("dd", 15, "woman", 4),
-				new Person("ee", 16, "woman", 5),
-				new Person("ff", 17, "man", 6)
+			new Person("aa", 12, "man", 1),
+			new Person("bb", 13, "woman", 2),
+			new Person("cc", 14, "man", 3),
+			new Person("dd", 15, "woman", 4),
+			new Person("ee", 16, "woman", 5),
+			new Person("ff", 17, "man", 6)
 		);
 
 		final Map<Integer, String> genderMap = new HashMap<>();
@@ -946,12 +947,12 @@ public class CollUtilTest {
 	@Test
 	public void distinctByFunctionTest() {
 		final List<Person> people = Arrays.asList(
-				new Person("aa", 12, "man", 1),
-				new Person("bb", 13, "woman", 2),
-				new Person("cc", 14, "man", 3),
-				new Person("dd", 15, "woman", 4),
-				new Person("ee", 16, "woman", 5),
-				new Person("ff", 17, "man", 6)
+			new Person("aa", 12, "man", 1),
+			new Person("bb", 13, "woman", 2),
+			new Person("cc", 14, "man", 3),
+			new Person("dd", 15, "woman", 4),
+			new Person("ee", 16, "woman", 5),
+			new Person("ff", 17, "man", 6)
 		);
 
 		// 覆盖模式下ff覆盖了aa，ee覆盖了bb
@@ -986,10 +987,10 @@ public class CollUtilTest {
 	@Test
 	public void mapBeanTest() {
 		final List<Person> people = Arrays.asList(
-				new Person("aa", 12, "man", 1),
-				new Person("bb", 13, "woman", 2),
-				new Person("cc", 14, "man", 3),
-				new Person("dd", 15, "woman", 4)
+			new Person("aa", 12, "man", 1),
+			new Person("bb", 13, "woman", 2),
+			new Person("cc", 14, "man", 3),
+			new Person("dd", 15, "woman", 4)
 		);
 
 		final List<Object> extract = CollUtil.map(people, Person::getName);
@@ -1006,10 +1007,10 @@ public class CollUtilTest {
 	@Test
 	public void transTest() {
 		final List<Person> people = Arrays.asList(
-				new Person("aa", 12, "man", 1),
-				new Person("bb", 13, "woman", 2),
-				new Person("cc", 14, "man", 3),
-				new Person("dd", 15, "woman", 4)
+			new Person("aa", 12, "man", 1),
+			new Person("bb", 13, "woman", 2),
+			new Person("cc", 14, "man", 3),
+			new Person("dd", 15, "woman", 4)
 		);
 
 		final Collection<String> trans = CollUtil.trans(people, Person::getName);
@@ -1046,8 +1047,8 @@ public class CollUtilTest {
 		Assertions.assertNotNull(list);
 
 		Assertions.assertEquals(
-				ListUtil.of(1, 2, 3, 4),
-				CollUtil.unionAll(ListUtil.of(1), ListUtil.of(2), ListUtil.of(3), ListUtil.of(4))
+			ListUtil.of(1, 2, 3, 4),
+			CollUtil.unionAll(ListUtil.of(1), ListUtil.of(2), ListUtil.of(3), ListUtil.of(4))
 		);
 	}
 
@@ -1083,14 +1084,14 @@ public class CollUtilTest {
 		Assertions.assertFalse(CollUtil.addIfAbsent(null, "123"));
 		Assertions.assertFalse(CollUtil.addIfAbsent(ListUtil.of("123"), "123"));
 		Assertions.assertFalse(CollUtil.addIfAbsent(ListUtil.of(new Animal("jack", 20)),
-				new Animal("jack", 20)));
+			new Animal("jack", 20)));
 
 		// 正常情况
 		Assertions.assertTrue(CollUtil.addIfAbsent(ListUtil.of("456"), "123"));
 		Assertions.assertTrue(CollUtil.addIfAbsent(ListUtil.of(new Animal("jack", 20)),
-				new Dog("jack", 20)));
+			new Dog("jack", 20)));
 		Assertions.assertTrue(CollUtil.addIfAbsent(ListUtil.of(new Animal("jack", 20)),
-				new Animal("tom", 20)));
+			new Animal("tom", 20)));
 	}
 
 	@Data
@@ -1181,4 +1182,51 @@ public class CollUtilTest {
 	public void minNullTest() {
 		Assertions.assertNull(CollUtil.max(null));
 	}
+
+
+	@Test
+	public void flatListTest1() {
+		List<List<List<String>>> list = Arrays.asList(Arrays.asList(Arrays.asList("1", "2", "3"), Arrays.asList("5", "6", "7")));
+
+		List<Object> objects = CollUtil.flat(list);
+
+		Assertions.assertArrayEquals(new String[]{"1", "2", "3", "5", "6", "7"}, objects.toArray());
+	}
+
+
+	@Test
+	public void flatListTest2() {
+		List<List<List<String>>> list = Arrays.asList(
+			Arrays.asList(
+				Arrays.asList("a"),
+				Arrays.asList("b", "c"),
+				Arrays.asList("d", "e", "f")
+			),
+			Arrays.asList(
+				Arrays.asList("g", "h", "i"),
+				Arrays.asList("j", "k", "l")
+			)
+		);
+		List<Object> flat = CollUtil.flat(list);
+		Assertions.assertArrayEquals(new String[]{"a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l"}, flat.toArray());
+
+	}
+
+
+	@Test
+	void flatListTest3() {
+		List<List<List<String>>> list = Arrays.asList(
+			Arrays.asList(
+				Arrays.asList("a"),
+				Arrays.asList("b", "c", null),
+				Arrays.asList("d", "e", "f")
+			),
+			Arrays.asList(
+				Arrays.asList("g", "h", "i"),
+				Arrays.asList("j", "k", "l")
+			)
+		);
+		List<Object> flat = CollUtil.flat(list, false);
+		Assertions.assertArrayEquals(new String[]{"a", "b", "c", null, "d", "e", "f", "g", "h", "i", "j", "k", "l"}, flat.toArray());
+	}
 }

hutool-core/src/test/java/org/dromara/hutool/core/collection/ListUtilTest.java

@@ -2,7 +2,6 @@ package org.dromara.hutool.core.collection;
 
 import lombok.AllArgsConstructor;
 import lombok.Data;
-import org.dromara.hutool.core.convert.Convert;
 import org.dromara.hutool.core.date.StopWatch;
 import org.dromara.hutool.core.lang.Console;
 import org.dromara.hutool.core.lang.page.PageInfo;
@@ -79,7 +78,7 @@ public class ListUtilTest {
 
 	@Test
 	public void splitAvgNotZero() {
-		Assertions.assertThrows(IllegalArgumentException.class, () -> {
+		Assertions.assertThrows(IllegalArgumentException.class, ()->{
 			// limit不能小于等于0
 			ListUtil.avgPartition(Arrays.asList(1, 2, 3, 4), 0);
 		});
@@ -123,7 +122,7 @@ public class ListUtilTest {
 	public void pageTest2() {
 		final List<Integer> a = ListUtil.ofLinked(1, 2, 3, 4, 5);
 		final int[] d1 = ListUtil.page(a, PageInfo.of(a.size(), 8).setFirstPageNo(0).setPageNo(0))
-			.stream().mapToInt(Integer::valueOf).toArray();
+				.stream().mapToInt(Integer::valueOf).toArray();
 		Assertions.assertArrayEquals(new int[]{1, 2, 3, 4, 5}, d1);
 	}
 
@@ -171,11 +170,11 @@ public class ListUtilTest {
 		}
 
 		final List<TestBean> beanList = ListUtil.of(
-			new TestBean(2, "test2"),
-			new TestBean(1, "test1"),
-			new TestBean(5, "test5"),
-			new TestBean(4, "test4"),
-			new TestBean(3, "test3")
+				new TestBean(2, "test2"),
+				new TestBean(1, "test1"),
+				new TestBean(5, "test5"),
+				new TestBean(4, "test4"),
+				new TestBean(3, "test3")
 		);
 
 		final List<TestBean> order = ListUtil.sortByProperty(beanList, "order");
@@ -246,13 +245,13 @@ public class ListUtilTest {
 	}
 
 	@Test
-	public void ofCopyOnWriteTest() {
+	public void ofCopyOnWriteTest(){
 		final CopyOnWriteArrayList<String> strings = ListUtil.ofCopyOnWrite(ListUtil.of("a", "b"));
 		Assertions.assertEquals(2, strings.size());
 	}
 
 	@Test
-	public void ofCopyOnWriteTest2() {
+	public void ofCopyOnWriteTest2(){
 		final CopyOnWriteArrayList<String> strings = ListUtil.ofCopyOnWrite("a", "b");
 		Assertions.assertEquals(2, strings.size());
 	}
@@ -270,22 +269,4 @@ public class ListUtilTest {
 
 		ListUtil.reverseNew(list);
 	}
-
-	@Test
-	public void flatListTest1() {
-		List<List<List<String>>> list = Arrays.asList(Arrays.asList(Arrays.asList("1", "2", "3"), Arrays.asList("5", "6", "7")));
-
-		List<String> objects = ListUtil.flatList(list);
-
-		Assertions.assertArrayEquals(new String[]{"1", "2", "3", "5", "6", "7"}, objects.toArray());
-	}
-
-
-	@Test
-	public void flatListTest2() {
-		List<List<List<String>>> list = Arrays.asList(Arrays.asList(Arrays.asList("1", "2", "3"), Arrays.asList("5", "6", "7")));
-
-		List<Integer> objects = ListUtil.flatList(list, Convert::toInt);
-		Assertions.assertArrayEquals(new Integer[]{1, 2, 3, 5, 6, 7}, objects.toArray());
-	}
 }