list - java程式碼最佳化

Question

現在的能跑，但是肯定寫的不好。

List<? extends WeatherData> data =  weatherReportDao.getCoviReportData(reportType);
WeatherENUM weatherENUM = WeatherENUM.valueOf(reportFunction);
switch (weatherENUM){
            case atmosphere:
                data =  atmosphereReportDao.getAtmosphereReportData(reportType);
                break;
            case covi:
                 data =  weatherReportDao.getCoviReportData(reportType);
                break;
            case windSpeed:
                data = windSpeedReportDao.getWindSpeedReportData(reportType);
                break;
        }
        return data;

關鍵就是data的初始化，不初始化會報錯。求指導。

Answer 1

List<? extends WeatherData> data = null;

或想辦法把weatherENUM的某個值當作參數傳到dao

List<? extends WeatherData> data =  weatherReportDao.getReportData(reportType,dataType);

Answer 2

定義成全域量就不用初始化了。