package com.fastbee.common.utils.collection; 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; /** * @author gsb * @date 2022/9/15 16:52 */ public class CollectionUtils { /*数组复制*/ public static String[] copy(String[] source){ if(isEmpty(source)){ return null; } int len = source.length; String[] arr = new String[len]; for(int i=0; i < len; i ++){ arr[i] = source[i]; } return arr; } /*数组连接*/ public static String concat(String[] source, String split){ if(isEmpty(source)){ return null; } String result = ""; for(int i=0; i < source.length; i ++){ result = result.concat(source[i]); if(i != source.length - 1){ result = result.concat(split); } } return result; } public static boolean isEmpty(String[] source){ if(null == source){ return true; } if(0 == source.length){ return true; } return false; } public static boolean containsAny(Object source, Object... targets) { return Arrays.asList(targets).contains(source); } public static boolean isAnyEmpty(Collection... collections) { return Arrays.stream(collections).anyMatch(CollectionUtil::isEmpty); } public static List filterList(Collection from, Predicate predicate) { if (CollUtil.isEmpty(from)) { return new ArrayList<>(); } return from.stream().filter(predicate).collect(Collectors.toList()); } public static List distinct(Collection from, Function keyMapper) { if (CollUtil.isEmpty(from)) { return new ArrayList<>(); } return distinct(from, keyMapper, (t1, t2) -> t1); } public static List distinct(Collection from, Function keyMapper, BinaryOperator cover) { if (CollUtil.isEmpty(from)) { return new ArrayList<>(); } return new ArrayList<>(convertMap(from, keyMapper, Function.identity(), cover).values()); } public static List convertList(Collection from, Function func) { if (CollUtil.isEmpty(from)) { return new ArrayList<>(); } return from.stream().map(func).filter(Objects::nonNull).collect(Collectors.toList()); } public static List convertList(Collection from, Function func, Predicate filter) { if (CollUtil.isEmpty(from)) { return new ArrayList<>(); } return from.stream().filter(filter).map(func).filter(Objects::nonNull).collect(Collectors.toList()); } public static Set convertSet(Collection from, Function func) { if (CollUtil.isEmpty(from)) { return new HashSet<>(); } return from.stream().map(func).filter(Objects::nonNull).collect(Collectors.toSet()); } public static Set convertSet(Collection from, Function func, Predicate filter) { if (CollUtil.isEmpty(from)) { return new HashSet<>(); } return from.stream().filter(filter).map(func).filter(Objects::nonNull).collect(Collectors.toSet()); } public static Map convertMap(Collection from, Function keyFunc) { if (CollUtil.isEmpty(from)) { return new HashMap<>(); } return convertMap(from, keyFunc, Function.identity()); } public static Map convertMap(Collection from, Function keyFunc, Supplier> supplier) { if (CollUtil.isEmpty(from)) { return supplier.get(); } return convertMap(from, keyFunc, Function.identity(), supplier); } public static Map convertMap(Collection from, Function keyFunc, Function valueFunc) { if (CollUtil.isEmpty(from)) { return new HashMap<>(); } return convertMap(from, keyFunc, valueFunc, (v1, v2) -> v1); } public static Map convertMap(Collection from, Function keyFunc, Function valueFunc, BinaryOperator mergeFunction) { if (CollUtil.isEmpty(from)) { return new HashMap<>(); } return convertMap(from, keyFunc, valueFunc, mergeFunction, HashMap::new); } public static Map convertMap(Collection from, Function keyFunc, Function valueFunc, Supplier> supplier) { if (CollUtil.isEmpty(from)) { return supplier.get(); } return convertMap(from, keyFunc, valueFunc, (v1, v2) -> v1, supplier); } public static Map convertMap(Collection from, Function keyFunc, Function valueFunc, BinaryOperator mergeFunction, Supplier> supplier) { if (CollUtil.isEmpty(from)) { return new HashMap<>(); } return from.stream().collect(Collectors.toMap(keyFunc, valueFunc, mergeFunction, supplier)); } public static Map> convertMultiMap(Collection from, Function keyFunc) { if (CollUtil.isEmpty(from)) { return new HashMap<>(); } return from.stream().collect(Collectors.groupingBy(keyFunc, Collectors.mapping(t -> t, Collectors.toList()))); } public static Map> convertMultiMap(Collection from, Function keyFunc, Function valueFunc) { if (CollUtil.isEmpty(from)) { return new HashMap<>(); } 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 public static Map> convertMultiMap2(Collection from, Function keyFunc, Function valueFunc) { if (CollUtil.isEmpty(from)) { return new HashMap<>(); } return from.stream().collect(Collectors.groupingBy(keyFunc, Collectors.mapping(valueFunc, Collectors.toSet()))); } public static boolean containsAny(Collection source, Collection candidates) { return org.springframework.util.CollectionUtils.containsAny(source, candidates); } public static T getFirst(List from) { return !CollectionUtil.isEmpty(from) ? from.get(0) : null; } public static T findFirst(List from, Predicate predicate) { if (CollUtil.isEmpty(from)) { return null; } return from.stream().filter(predicate).findFirst().orElse(null); } public static > V getMaxValue(List from, Function valueFunc) { if (CollUtil.isEmpty(from)) { return null; } assert from.size() > 0; // 断言,避免告警 T t = from.stream().max(Comparator.comparing(valueFunc)).get(); return valueFunc.apply(t); } public static > V getMinValue(List from, Function valueFunc) { if (CollUtil.isEmpty(from)) { return null; } assert from.size() > 0; // 断言,避免告警 T t = from.stream().min(Comparator.comparing(valueFunc)).get(); return valueFunc.apply(t); } public static > V getSumValue(List from, Function valueFunc, BinaryOperator accumulator) { if (CollUtil.isEmpty(from)) { return null; } assert from.size() > 0; // 断言,避免告警 return from.stream().map(valueFunc).reduce(accumulator).get(); } public static void addIfNotNull(Collection coll, T item) { if (item == null) { return; } coll.add(item); } public static Collection singleton(T deptId) { return deptId == null ? Collections.emptyList() : Collections.singleton(deptId); } }