文件内容转换成String、Json数据格式转换、Json文件序列化数据库总结

需求：将json格式的文件序列化为一个对象、并存入数据库，文件内容如下：

{
	"user": [{
		"id": "1",
		"user_name": "小米",
		"age": "18",
		"phone": "132677",
		"CREATE_BY": "admin",
		"CREATE_DATE": "2021-04-04 09:23:45",
		"MODIFIED_BY": "admin",
		"MODIFIED_DATE": "2021-05-01 09:23:45"
	}],
	"role": [{
		"ID": "1",
		"role_name": "普通用户"
		"CREATE_BY": "admin",
		"CREATE_DATE": "2021-04-04 09:23:45",
		"MODIFIED_BY": "admin",
		"MODIFIED_DATE": "2021-05-01 09:23:45"
	}]
}

整个文件是一个Json对象，由{}括起来，所以首先将读取文件内容

 /**
 * 将文件内容读取成一个字符串
 */
private String readFileAsString(MultipartFile file) {
    //读取文件，转化为String
    BufferedReader reader = null;
    String data = "";
    try {
        System.out.println(file.getName());
        InputStream inputStream = file.getInputStream();
        InputStreamReader inputStreamReader = new InputStreamReader(inputStream, "UTF-8");
        reader = new BufferedReader(inputStreamReader);
        String tempString = null;
        while ((tempString = reader.readLine()) != null) {
            data += tempString;
        }
        reader.close();

    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        //关闭流对象
        if (reader != null) {
            try {
                reader.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
    return s;
}

然后解析json字符串

    JSONObject jsonObject = JSON.parseObject(s);

获取jsonObject 的key集合

 Set<String> keys = jsonObject.keySet();

遍历key，获取value

keys.forEach(key -> {
            JSONArray jsonArray = jsonObject.getJSONArray(key);
            //四、对key进行表名判断
            if ("user".equalsIgnoreCase(key)) {
                List<User> list = new ArrayList<>();
                //五、遍历JSON数组
                jsonArray.forEach(o -> {
                    User user = JSON.toJavaObject((JSONObject) o, User.class);
                    list.add(user );
                });     
                //批量插入数据库
                userMapper.insertData(list);
            }else if("role".equalsIgnoreCase(key)){
            	 List<Role> list = new ArrayList<>();
                //五、遍历JSON数组
                jsonArray.forEach(o -> {
                    Role  role = JSON.toJavaObject((JSONObject) o, Role.class);
                    list.add(role );
                });     
                //批量插入数据库
                roleMapper.insertData(list);
			}
    });
}