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!27 CollectionUtils 新增distinct、convertMap 重载函数

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Merge pull request !27 from 贺小五/feature/coll
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芋道源码 2021-04-11 00:41:24 +08:00 committed by Gitee
commit 8a9c714586
1 changed files with 49 additions and 6 deletions
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55
src/main/java/cn/iocoder/dashboard/util/collection/CollectionUtils.java
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@ -4,8 +4,10 @@ import cn.hutool.core.collection.CollUtil;
import cn.hutool.core.collection.CollectionUtil;
import java.util.*;
import java.util.function.BinaryOperator;
import java.util.function.Function;
import java.util.function.Predicate;
import java.util.function.Supplier;
import java.util.stream.Collectors;
/**
@ -30,6 +32,20 @@ public class CollectionUtils {
return from.stream().filter(predicate).collect(Collectors.toList());
}
public static <T, R> List<T> distinct(Collection<T> from, Function<T, R> keyMapper) {
if (CollUtil.isEmpty(from)) {
return new ArrayList<>();
}
return distinct(from, keyMapper, (t1, t2) -> t1);
}
public static <T, R> List<T> distinct(Collection<T> from, Function<T, R> keyMapper, BinaryOperator<T> cover) {
if (CollUtil.isEmpty(from)) {
return new ArrayList<>();
}
return new ArrayList<>(convertMap(from, keyMapper, Function.identity(), cover).values());
}
public static <T, U> List<U> convertList(Collection<T> from, Function<T, U> func) {
if (CollUtil.isEmpty(from)) {
return new ArrayList<>();
@ -48,30 +64,57 @@ public class CollectionUtils {
if (CollUtil.isEmpty(from)) {
return new HashMap<>();
}
return from.stream().collect(Collectors.toMap(keyFunc, item -> item));
return convertMap(from, keyFunc, Function.identity());
}
public static <T, K> Map<K, T> convertMap(Collection<T> from, Function<T, K> keyFunc, Supplier<? extends Map<K, T>> supplier) {
if (CollUtil.isEmpty(from)) {
return supplier.get();
}
return convertMap(from, keyFunc, Function.identity(), supplier);
}
public static <T, K, V> Map<K, V> convertMap(Collection<T> from, Function<T, K> keyFunc, Function<T, V> valueFunc) {
if (CollUtil.isEmpty(from)) {
return new HashMap<>();
}
return from.stream().collect(Collectors.toMap(keyFunc, valueFunc));
return convertMap(from, keyFunc, valueFunc, (v1, v2) -> v1);
}
public static <T, K, V> Map<K, V> convertMap(Collection<T> from, Function<T, K> keyFunc, Function<T, V> valueFunc, BinaryOperator<V> mergeFunction) {
if (CollUtil.isEmpty(from)) {
return new HashMap<>();
}
return convertMap(from, keyFunc, valueFunc, mergeFunction, HashMap::new);
}
public static <T, K, V> Map<K, V> convertMap(Collection<T> from, Function<T, K> keyFunc, Function<T, V> valueFunc, Supplier<? extends Map<K, V>> supplier) {
if (CollUtil.isEmpty(from)) {
return supplier.get();
}
return convertMap(from, keyFunc, valueFunc, (v1, v2) -> v1, supplier);
}
public static <T, K, V> Map<K, V> convertMap(Collection<T> from, Function<T, K> keyFunc, Function<T, V> valueFunc, BinaryOperator<V> mergeFunction, Supplier<? extends Map<K, V>> supplier) {
if (CollUtil.isEmpty(from)) {
return new HashMap<>();
}
return from.stream().collect(Collectors.toMap(keyFunc, valueFunc, mergeFunction, supplier));
}
public static <T, K> Map<K, List<T>> convertMultiMap(Collection<T> from, Function<T, K> keyFunc) {
if (CollUtil.isEmpty(from)) {
return new HashMap<>();
}
return from.stream().collect(Collectors.groupingBy(keyFunc,
Collectors.mapping(t -> t, Collectors.toList())));
return from.stream().collect(Collectors.groupingBy(keyFunc, Collectors.mapping(t -> t, Collectors.toList())));
}
public static <T, K, V> Map<K, List<V>> convertMultiMap(Collection<T> from, Function<T, K> keyFunc, Function<T, V> valueFunc) {
if (CollUtil.isEmpty(from)) {
return new HashMap<>();
}
return from.stream().collect(Collectors.groupingBy(keyFunc,
Collectors.mapping(valueFunc, Collectors.toList())));
return from.stream()
.collect(Collectors.groupingBy(keyFunc, Collectors.mapping(valueFunc, Collectors.toList())));
}
// 暂时没想好名字，先以 2 结尾噶