java中Map List<E>的用法

最新推荐文章于 2024-02-18 13:30:22 发布

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#map list #restful

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本文介绍如何将RESTful接口返回的数据解析并映射到Java实体类中，包括定义实体类WzwScreenEntity和WzwScreenChildEntity，以及如何使用这些实体类从数据库查询数据并组织成特定的Map数据结构。

返回的restful接口数据样式：

{
     party: [
         {
             "finishTime": "20191105",
             "busiCnt": 1000
         }
     ]
 }

1、定义WzwScreenEntity 实体

public class WzwScreenEntity {

    private String finishTime;
    private String busiCnt;
    private String party;

    public String getFinishTime() {
        return finishTime;
    }

    public void setFinishTime(String finishTime) {
        this.finishTime = finishTime;
    }

    public String getBusiCnt() {
        return busiCnt;
    }

    public void setBusiCnt(String busiCnt) {
        this.busiCnt = busiCnt;
    }

    public String getParty() {
        return party;
    }

    public void setParty(String party) {
        this.party = party;
    }
}

2、定义list实体

public class WzwScreenChildEntity {
    public String getFinishTime() {
        return finishTime;
    }

    public void setFinishTime(String finishTime) {
        this.finishTime = finishTime;
    }

    public String getBusiCnt() {
        return busiCnt;
    }

    public void setBusiCnt(String busiCnt) {
        this.busiCnt = busiCnt;
    }

    private String finishTime;
    private String busiCnt;
}

3、具体实现

List<WzwScreenEntity> scList = new ArrayList<>();
scList  = mapper.queryData();//从数据库获取数据
Map<String, List> map = new HashMap<>();//定义返回的map

if (scList.size() != 0) {
    for (WzwScreenEntity entity : scList) {
        WzwScreenChildEntity childEntity = new WzwScreenChildEntity();
        childEntity.setFinishTime(entity.getFinishTime());
        childEntity.setBusiCnt(entity.getBusiCnt());

        List<WzwScreenChildEntity> list = new ArrayList<>();
        list.add(childEntity);

		//当map中的key相同的，防止value值被覆盖。
        if (map.containsKey(entity.getParty())) {
            list.addAll(map.get(entity.getParty()));
            map.put(entity.getParty(), list);
        } else {
            map.put(entity.getParty(), list);
        }
    }
}
LOGGER.info("map================== " + map);