java中，jdk1.8stream

List<Map>转List<实体>

//javaBean是实体类
List<javaBean> collect = result.stream()
                    .map(map -> JSON.parseObject(JSON.toJSONString(map),javaBean.class))
                    .collect(Collectors.toList());

List<实体>转List<Map>

 
        List<UWBR0501> rows = dao.query("UWBR0501.query", params, offset * limit, limit);
                //实体转map
                List<Map> result = rows.stream().map(iter -> {
                    Map<String, Object> map = JSON.parseObject(JSON.toJSONString(iter),               Map.class);
                    return map;
                }).collect(Collectors.toList());

List<Map/Bean>转换成Map

List<String> list = Arrays.asList("apple", "banana", "orange");

// List<String> 转换成Map
Map<String, Integer> map = list.stream()
    .collect(Collectors.toMap(Function.identity(), String::length));

// List<String> 转换成Map
Map<String, Integer> map = list.stream()
    .collect(Collectors.toMap(s -> s, s -> s.length()));

List<Map/Bean>转List<String>

 List<String> idList=nodeList.stream().map(Node::getId).collect(Collectors.toList());

groupingBy

//List<Bean> 转换成map,key为两个属性拼接
Map<String, List<Bean>> weekSectionMap = schedulesList.stream().collect(Collectors.groupingBy(item -> item.getField1() + "_" + item.getField2()));

深度转换

List<UserSecurity> result=JSONObject.parseObject(res, new TypeReference<List<UserSecurity>>() {
});

筛选

notices.stream().anyMatch(notice -> Arrays.stream(notice.getNoticeType().split(",")).collect(Collectors.toSet()).contains(String.valueOf(finalNoticeType))) ? 1 : 0;

排序

//从大到小
list.stream().sorted(Comparator.comparing(DurationVo::getDuration)).collect(Collectors.toList());
//从小到大
list.stream().sorted(Comparator.comparing(DurationVo::getDuration).reversed()).collect(Collectors.toList());