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add method

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Looly
2021-12-21 23:56:43 +08:00
parent e2710ae79e
commit 9768a4d080
3 changed files with 31 additions and 20 deletions
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14
hutool-core/src/test/java/cn/hutool/core/collection/CollStreamUtilTest.java
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@@ -8,7 +8,6 @@ import org.junit.Assert;
import org.junit.Test;
import java.util.*;
import java.util.function.Function;
import java.util.stream.Collector;
import java.util.stream.Collectors;
@@ -173,16 +172,16 @@ public class CollStreamUtilTest {
}
@Test
public void testGroupThen() {
// groupThen作为之前所有group函数的公共部分抽取出来，并更接近于jdk原生，灵活性更强
public void testGroupBy() {
// groupBy作为之前所有group函数的公共部分抽取出来，并更接近于jdk原生，灵活性更强
// 参数null测试
Map<Long, List<Student>> map = CollStreamUtil.groupThen(null, Student::getTermId, Collectors.toList());
Map<Long, List<Student>> map = CollStreamUtil.groupBy(null, Student::getTermId, Collectors.toList());
Assert.assertEquals(map, Collections.EMPTY_MAP);
// 参数空数组测试
List<Student> list = new ArrayList<>();
map = CollStreamUtil.groupThen(list, Student::getTermId, Collectors.toList());
map = CollStreamUtil.groupBy(list, Student::getTermId, Collectors.toList());
Assert.assertEquals(map, Collections.EMPTY_MAP);
// 放入元素
@@ -190,11 +189,12 @@ public class CollStreamUtilTest {
list.add(new Student(1, 2, 1, "李四"));
list.add(new Student(2, 2, 1, "王五"));
// 先根据termId分组，再通过classId比较，找出最大值所属的那个Student,返回的Optional
Map<Long, Optional<Student>> longOptionalMap = CollStreamUtil.groupThen(list, Student::getTermId, Collectors.maxBy(Comparator.comparing(Student::getClassId)));
Map<Long, Optional<Student>> longOptionalMap = CollStreamUtil.groupBy(list, Student::getTermId, Collectors.maxBy(Comparator.comparing(Student::getClassId)));
//noinspection OptionalGetWithoutIsPresent
Assert.assertEquals("李四", longOptionalMap.get(1L).get().getName());
// 先根据termId分组，再转换为Map<studentId,name>
Map<Long, HashMap<Long, String>> groupThen = CollStreamUtil.groupThen(list, Student::getTermId, Collector.of(HashMap::new, (m, v) -> m.put(v.getStudentId(), v.getName()), (l, r) -> l));
Map<Long, HashMap<Long, String>> groupThen = CollStreamUtil.groupBy(list, Student::getTermId, Collector.of(HashMap::new, (m, v) -> m.put(v.getStudentId(), v.getName()), (l, r) -> l));
Assert.assertEquals(
MapUtil.builder()
.put(1L, MapUtil.builder().put(1L, "李四").build())