【工具类】-Map

Map

1. entrySet遍历，在键和值都需要时使用（最常用）

  Map<Integer, Integer> map = new HashMap<Integer, Integer>();
        map.put(1, 2);

        for (Map.Entry<Integer, Integer> entry : map.entrySet()) {
            System.out.println("key = " + entry.getKey() + ", value = " + entry.getValue());
        }

2. key遍历

Map<Long, OtaTask> result = new LinkedHashMap<>();
for (Long taskId : result.keySet()) {}

3.map根据key排序

Map<Long, OtaTask> result = new LinkedHashMap<>();
   // 倒叙
   tasksMap.entrySet().stream().sorted(Collections.reverseOrder(Map.Entry.comparingByKey())).
   forEachOrdered(x -> result.put(x.getKey(), x.getValue()));

// 正序
   tasksMap.entrySet().stream().sorted(Map.Entry.comparingByKey()).
   forEachOrdered(x -> result.put(x.getKey(), x.getValue()));

对象转map

import cn.hutool.core.bean.BeanUtil;
Map map = new HashMap();
BeanUtil.copyProperties(queryRecordForm, map);