72 lines
2.3 KiB
Java
72 lines
2.3 KiB
Java
package com.hmall.common.utils;
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import cn.hutool.core.collection.CollectionUtil;
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import cn.hutool.core.collection.IterUtil;
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import cn.hutool.core.util.NumberUtil;
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import java.util.*;
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import java.util.stream.Collectors;
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/**
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* 继承自 hutool 的集合工具类
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*/
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public class CollUtils extends CollectionUtil {
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public static <T> List<T> emptyList() {
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return Collections.emptyList();
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}
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public static <T> Set<T> emptySet() {
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return Collections.emptySet();
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}
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public static <K,V> Map<K, V> emptyMap() {
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return Collections.emptyMap();
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}
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public static <T> Set<T> singletonSet(T t) {
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return Collections.singleton(t);
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}
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public static <T> List<T> singletonList(T t) {
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return Collections.singletonList(t);
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}
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public static List<Integer> convertToInteger(List<String> originList){
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return CollUtils.isNotEmpty(originList) ? originList.stream().map(NumberUtil::parseInt).collect(Collectors.toList()) : null;
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}
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public static List<Long> convertToLong(List<String> originLIst){
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return CollUtils.isNotEmpty(originLIst) ? originLIst.stream().map(NumberUtil::parseLong).collect(Collectors.toList()) : null;
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}
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/**
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* 以 conjunction 为分隔符将集合转换为字符串 如果集合元素为数组、Iterable或Iterator，则递归组合其为字符串
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* @param collection 集合
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* @param conjunction 分隔符
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* @param <T> 集合元素类型
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* @return 连接后的字符串
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* See Also: IterUtil.join(Iterator, CharSequence)
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*/
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public static <T> String join(Collection<T> collection, CharSequence conjunction) {
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if (null == collection || collection.isEmpty()) {
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return null;
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}
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return IterUtil.join(collection.iterator(), conjunction);
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}
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public static <T> String joinIgnoreNull(Collection<T> collection, CharSequence conjunction) {
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if (null == collection || collection.isEmpty()) {
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return null;
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}
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StringBuilder sb = new StringBuilder();
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for (T t : collection) {
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if(t == null) continue;
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sb.append(t).append(",");
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}
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if(sb.length() <= 0){
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return null;
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}
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return sb.deleteCharAt(sb.length() - 1).toString();
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}
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} |