JSON、List---转换

目录

转 Map

        maven 依赖

        转换

转 List

        maven依赖

        转换

---

JSON转 Map

JSON格式为  {key:value,key2:value2,......} 

        maven 依赖

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.28</version>
        </dependency>

        转换

String str = "{key:value,key2:value2,......}"
JSONObject jsonObject = new JSONObject(str);
String ContentStr = jsonObject.toString();
Map<String, Object> Content = JSONObject.parseObject(ContentStr, new TypeReference<Map<String, Object>>() {});

JSON转 List

JSON格式为  [{key:value,key2:value2,......}] 

        maven依赖

        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.13.0</version>
        </dependency>

        转换

ObjectMapper objectMapper = new ObjectMapper();
List<Map<String, Object>> list = objectMapper.readValue(Content, new com.fasterxml.jackson.core.type.TypeReference<List<Map<String, Object>>>() {});

List 转 Map

Map<String, Entity> collect = EntityMapper.queryDataList(null).stream().collect(Collectors.toMap(Entity::getId, Function.identity(), (key1, key2) -> key2));

Function.identity() 实体类为 map 的值

或

Entity::getName        某个字段为 map 的值

(key1, key2) -> key2)        出现相同键，值保留的处理方式

                                                                Cheung Kwok Wing 随笔