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  • stream流 list转map

    package com.mayikt.stream;
    
    import com.mayikt.entity.UserEntity;
    
    import java.util.ArrayList;
    import java.util.Map;
    import java.util.function.BiConsumer;
    import java.util.function.Function;
    import java.util.stream.Collectors;
    import java.util.stream.Stream;
    
    /**
     * @ClassName Test02
     * @Author 蚂蚁课堂余胜军 QQ644064779 www.mayikt.com
     * @Version V1.0
     **/
    public class Test02 {
        public static void main(String[] args) {
            ArrayList<UserEntity> userEntities = new ArrayList<>();
            userEntities.add(new UserEntity("mayikt", 20));
            userEntities.add(new UserEntity("meite", 28));
            userEntities.add(new UserEntity("zhangsan", 35));
    
            // list集合只有元素值 key list转换成map集合的情况下 指定key--user对象 username属性  value user对象
            /**
             * map<String(userName),UserEntity>
             */
            Stream<UserEntity> stream = userEntities.stream();
            /**
             * new Function<UserEntity(list集合中的类型), String(key map)>
             */
            Map<String, UserEntity> collect = stream.collect(Collectors.toMap(userEntity -> userEntity.getUserName(), userEntity -> userEntity));
            collect.forEach((BiConsumer) (o, o2) -> System.out.println(o + "," + o2));
        }
    }
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  • 原文地址:https://www.cnblogs.com/angdh/p/15596327.html
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