修改最美志愿者编辑报错id为空

lidongdong

2023-08-17 5b1f8540b5843578a80e4aa34e371f1a5b40f31e

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package com.panzhihua.common.utlis;
 
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.function.Function;
import java.util.function.Predicate;
 
public class ListUtils {
 
    public static <T> Predicate<T> distinctByKey(Function<? super T, Object> keyExtractor) {
        Map<Object, Boolean> seen = new ConcurrentHashMap<>();
        return t -> seen.putIfAbsent(keyExtractor.apply(t), Boolean.TRUE) == null;
    }
}