使用Lambda表達式.map循環遍歷List集合賦值

使用Lambda表達式給對象賦值

0. 技術點

• 使用Lambda表達式.map循環遍歷List集合賦值

1. 實體類

@Data
public class InfoNoticeItem implements Serializable {
    /**
     * serialVersionUID
     */
    private static final long serialVersionUID = 6411598034131994800L;
    /**
     * ids 商品內碼
     */
    private String ids;

    /**
     * storeCode 門店編號
     */
    private String storeCode;
}

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2. 測試類

import com.alibaba.fastjson.JSON;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.stream.Collectors;

public class Test {
    public static void main(String[] args) {

        InfoNoticeItem re2 = new InfoNoticeItem();
        re2.setIds("2");
        re2.setStoreCode("高佳琪");

        InfoNoticeItem re4 = new InfoNoticeItem();
        re4.setIds("4");
        re4.setStoreCode("王瑩瑩");

        List<InfoNoticeItem> list = new ArrayList<>();
        Collections.addAll(list, re2, re4);

        ShopInfoNoticeReq shopInfoNoticeReq = new ShopInfoNoticeReq();
        shopInfoNoticeReq.setFormat(null);
        shopInfoNoticeReq.setIdList(list);

        // 賦值.setIdList(collect)
        // public void setIdList(List<InfoNoticeItem> idList)
        List<InfoNoticeItem> collect = shopInfoNoticeReq.getIdList().stream().map(item -> {
            InfoNoticeItem ini = new InfoNoticeItem();
            ini.setIds(item.getIds());
            ini.setStoreCode(item.getStoreCode());
            return ini;
        }).collect(Collectors.toList());

        try {
            Thread.sleep(2000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        System.out.println(JSON.toJSON(collect));
        //TODO 輸出：[{"ids":"2","storeCode":"高佳琪"},{"ids":"4","storeCode":"王瑩瑩"}]
    }
}

---

簡單使用

  ArrayList<Student> list = new ArrayList<>();
  Collections.addAll(list, new Student(0, "張三"), new Student(10, "李四"));

  System.out.println(list.stream().map(value -> value.getId()).collect(Collectors.toList()));
  System.out.println(list.stream().map(Student::getId).collect(Collectors.toList()));
  //輸出: [0, 10]
  //輸出: [0, 10]