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修复CollectorUtil.reduceListMap与collectors.groupby一起使用时出现与预期不符问题

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This commit is contained in:
Looly 2023-11-12 16:46:10 +08:00
parent da1e857c07
commit 7a4cac2963
2 changed files with 50 additions and 28 deletions
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57
hutool-core/src/main/java/org/dromara/hutool/core/stream/CollectorUtil.java
View File

@ -35,7 +35,7 @@ public class CollectorUtil {
* 说明已包含IDENTITY_FINISH特征 为 Characteristics.IDENTITY_FINISH 的缩写
*/
public static final Set<Collector.Characteristics> CH_ID
= Collections.unmodifiableSet(EnumSet.of(Collector.Characteristics.IDENTITY_FINISH));
= Collections.unmodifiableSet(EnumSet.of(Collector.Characteristics.IDENTITY_FINISH));
/**
* 说明不包含IDENTITY_FINISH特征
*/
@ -80,11 +80,11 @@ public class CollectorUtil {
final CharSequence suffix,
final Function<T, ? extends CharSequence> toStringFunc) {
return new SimpleCollector<>(
() -> new StringJoiner(delimiter, prefix, suffix),
(joiner, ele) -> joiner.add(toStringFunc.apply(ele)),
StringJoiner::merge,
StringJoiner::toString,
Collections.emptySet()
() -> new StringJoiner(delimiter, prefix, suffix),
(joiner, ele) -> joiner.add(toStringFunc.apply(ele)),
StringJoiner::merge,
StringJoiner::toString,
Collections.emptySet()
);
}
@ -208,11 +208,11 @@ public class CollectorUtil {
* 提供对null值友好的groupingBy操作的{@link Collector}实现，
* 对集合分组，然后对分组后的值集合进行映射
*
* @param classifier 分组依据
* @param valueMapper 值映射方法
* @param <T> 元素类型
* @param <K> 键类型
* @param <R> 值类型
* @param classifier 分组依据
* @param valueMapper 值映射方法
* @param <T> 元素类型
* @param <K> 键类型
* @param <R> 值类型
* @return {@link Collector}
*/
public static <T, K, R> Collector<T, ?, Map<K, List<R>>> groupingBy(
@ -284,7 +284,7 @@ public class CollectorUtil {
final BinaryOperator<U> mergeFunction,
final Supplier<M> mapSupplier) {
final BiConsumer<M, T> accumulator
= (map, element) -> map.put(Opt.ofNullable(element).map(keyMapper).get(), Opt.ofNullable(element).map(valueMapper).get());
= (map, element) -> map.put(Opt.ofNullable(element).map(keyMapper).get(), Opt.ofNullable(element).map(valueMapper).get());
return new SimpleCollector<>(mapSupplier, accumulator, mapMerger(mergeFunction), CH_ID);
}
@ -330,13 +330,18 @@ public class CollectorUtil {
*/
public static <K, V, R extends Map<K, List<V>>> Collector<Map<K, V>, ?, R> reduceListMap(final Supplier<R> mapSupplier) {
return Collectors.reducing(mapSupplier.get(), value -> {
final R result = mapSupplier.get();
value.forEach((k, v) -> result.computeIfAbsent(k, i -> new ArrayList<>()).add(v));
return result;
}, (l, r) -> {
r.forEach((k, v) -> l.computeIfAbsent(k, i -> new ArrayList<>()).addAll(v));
return l;
}
final R result = mapSupplier.get();
value.forEach((k, v) -> result.computeIfAbsent(k, i -> new ArrayList<>()).add(v));
return result;
}, (l, r) -> {
final R resultMap = mapSupplier.get();
resultMap.putAll(l);
r.forEach((k, v) -> {
final List<V> list = resultMap.computeIfAbsent(k, i -> new ArrayList<>());
list.addAll(v);
});
return resultMap;
}
);
}
@ -350,7 +355,7 @@ public class CollectorUtil {
* @since 6.0.0
*/
public static <T, K> Collector<T, List<T>, EntryStream<K, T>> toEntryStream(
final Function<? super T, ? extends K> keyMapper) {
final Function<? super T, ? extends K> keyMapper) {
return toEntryStream(keyMapper, Function.identity());
}
@ -366,7 +371,7 @@ public class CollectorUtil {
* @since 6.0.0
*/
public static <T, K, V> Collector<T, List<T>, EntryStream<K, V>> toEntryStream(
final Function<? super T, ? extends K> keyMapper, final Function<? super T, ? extends V> valueMapper) {
final Function<? super T, ? extends K> keyMapper, final Function<? super T, ? extends V> valueMapper) {
Objects.requireNonNull(keyMapper);
Objects.requireNonNull(valueMapper);
return transform(ArrayList::new, list -> EntryStream.of(list, keyMapper, valueMapper));
@ -401,11 +406,11 @@ public class CollectorUtil {
* @since 6.0.0
*/
public static <T, R, C extends Collection<T>> Collector<T, C, R> transform(
final Supplier<C> collFactory, final Function<C, R> mapper) {
final Supplier<C> collFactory, final Function<C, R> mapper) {
Objects.requireNonNull(collFactory);
Objects.requireNonNull(mapper);
return new SimpleCollector<>(
collFactory, C::add, (l1, l2) -> {
collFactory, C::add, (l1, l2) -> {
l1.addAll(l2);
return l1;
}, mapper, CH_NOID
@ -458,8 +463,8 @@ public class CollectorUtil {
final Collector<? super T, A, R> downstream) {
final BiConsumer<A, ? super T> downstreamAccumulator = downstream.accumulator();
return new SimpleCollector<>(downstream.supplier(),
(r, t) -> Opt.of(t).filter(predicate).ifPresent(e -> downstreamAccumulator.accept(r, e)),
downstream.combiner(), downstream.finisher(),
downstream.characteristics());
(r, t) -> Opt.of(t).filter(predicate).ifPresent(e -> downstreamAccumulator.accept(r, e)),
downstream.combiner(), downstream.finisher(),
downstream.characteristics());
}
}

21
hutool-core/src/test/java/org/dromara/hutool/core/stream/CollectorUtilTest.java
View File

@ -12,6 +12,7 @@
package org.dromara.hutool.core.stream;
import org.dromara.hutool.core.collection.ListUtil;
import org.dromara.hutool.core.map.MapUtil;
import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.Test;
@ -44,6 +45,22 @@ public class CollectorUtilTest {
Assertions.assertEquals(MapUtil.builder("苏格拉底", Arrays.asList(1, 2))
.put("特拉叙马霍斯", Arrays.asList(3, 1, 2)).build(),
nameScoresMap);
final List<Map<String, String>> data = ListUtil.of(
MapUtil.builder("name", "sam").put("count", "80").map(),
MapUtil.builder("name", "sam").put("count", "81").map(),
MapUtil.builder("name", "sam").put("count", "82").map(),
MapUtil.builder("name", "jack").put("count", "80").map(),
MapUtil.builder("name", "jack").put("count", "90").map()
);
final Map<String, Map<String, List<String>>> nameMap = data.stream()
.collect(Collectors.groupingBy(e -> e.get("name"), CollectorUtil.reduceListMap()));
Assertions.assertEquals(MapUtil.builder("jack", MapUtil.builder("name", Arrays.asList("jack", "jack"))
.put("count", Arrays.asList("80", "90")).build())
.put("sam", MapUtil.builder("name", Arrays.asList("sam", "sam", "sam"))
.put("count", Arrays.asList("80", "81", "82")).build())
.build(), nameMap);
}
@Test
@ -93,7 +110,7 @@ public class CollectorUtilTest {
@Test
public void testGroupingByAfterValueMapped() {
List<Integer> list = Arrays.asList(1, 1, 2, 2, 3, 4);
final List<Integer> list = Arrays.asList(1, 1, 2, 2, 3, 4);
Map<Boolean, Set<String>> map = list.stream()
.collect(CollectorUtil.groupingBy(t -> (t & 1) == 0, String::valueOf, LinkedHashSet::new, LinkedHashMap::new));
@ -107,7 +124,7 @@ public class CollectorUtilTest {
Assertions.assertEquals(new LinkedHashSet<>(Arrays.asList("2", "4")), map.get(Boolean.TRUE));
Assertions.assertEquals(new LinkedHashSet<>(Arrays.asList("1", "3")), map.get(Boolean.FALSE));
Map<Boolean, List<String>> map2 = list.stream()
final Map<Boolean, List<String>> map2 = list.stream()
.collect(CollectorUtil.groupingBy(t -> (t & 1) == 0, String::valueOf));
Assertions.assertEquals(Arrays.asList("2", "2", "4"), map2.get(Boolean.TRUE));
Assertions.assertEquals(Arrays.asList("1", "1", "3"), map2.get(Boolean.FALSE));