Java21读写Json文件

Posted 2021-12-05 huashengweilong

正文：

1，通用读取方法，返回map

    public static List<Map> JsonRead(HttpServletRequest request, String path) {
        List<Map> maps = null;
        String dir = request.getSession().getServletContext().getRealPath(path);
        System.out.println(path);
        System.out.println(dir);
        if (dir == null) {
            System.out.println("找不到数据");
            return null;
        }
        try {
            File file = new File(dir);
            if (!file.exists()) {
                file.createNewFile();
            }
            String str = FileUtils.readFileToString(file, "UTF-8");
            maps = (List) JSONArray.fromObject(str);
        } catch (IOException e) {
            e.printStackTrace();
        }
        return maps;
    };

2，先定义好实体类

public static void test() {
    ObjectMapper mapper = new ObjectMapper();
    TypeFactory typeFactory = mapper.getTypeFactory();
    CollectionType collectionType = typeFactory.constructCollectionType(List.class, SpringMonthVo.class);
    List<SpringMonthVo> list = new ArrayList<>();
    try {
        InputStream is = SpringMonthVo.class.getResourceAsStream("/springMonth.json");
        list = mapper.readValue(is, collectionType);
    } catch (IOException e) {
        e.printStackTrace();
    }
}

见我的博客的<13，是否是中国春节月>

【Java】【19】Date Calendar相关 - 花生喂龙 - 博客园
https://www.cnblogs.com/huashengweilong/p/10825007.html

参考博客：

java如何读写json文件 - <&nbsp/> - 博客园
https://www.cnblogs.com/zhangdiIT/p/7590472.html