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ListUtil添加解构list内部的多个list为单个list的方法

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This commit is contained in:
kongweiguang 2023-06-25 13:59:30 +08:00
parent 095507a86d
commit 7cb8492f18
2 changed files with 71 additions and 9 deletions
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43
hutool-core/src/main/java/org/dromara/hutool/core/collection/ListUtil.java
View File

@ -27,6 +27,7 @@ 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;
/**
@ -748,4 +749,46 @@ 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;
}
}

37
hutool-core/src/test/java/org/dromara/hutool/core/collection/ListUtilTest.java
View File

@ -2,6 +2,7 @@ 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;
@ -78,7 +79,7 @@ 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);
});
@ -122,7 +123,7 @@ 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);
}
@ -170,11 +171,11 @@ 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");
@ -245,13 +246,13 @@ 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());
}
@ -269,4 +270,22 @@ 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());
}
}