Springboot 在項目啓動時將數據緩存到全局變量

聲明：

有寫字典數據不會頻繁更新，但是會頻繁查詢，想要減少數據庫鏈接次數，把內容緩存到項目的全局變量中，提高方法查詢速度

 

代碼：

import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

@Component
public class CodeCache {
    public static Map<String, TownNameDto> codeMap = new HashMap<String, TownNameDto>();
    public static Map<String, CompanyModel> companyMap = new HashMap<String, CompanyModel>();

    @Autowired
    private CityDao cityDao;
    @Autowired
    private CompanyDao companyDao;


    @PostConstruct
    public void init() {
        //系統啓動中。。。加載codeMap
        List<TownNameDto> codeList = cityDao.selectCityNameAndCodeALL();
        for (TownNameDto code : codeList) {
            codeMap.put(code.getTownCode() + code.getValue(), code);
        }
        List<CompanyModel> companyModels = companyDao.selectCompanies();
        for (CompanyModel company : companyModels) {
            companyMap.put(company.getCode(), company);
        }


    }

    @PreDestroy
    public void destroy() {
        //系統運行結束
    }

    @Scheduled(cron = "0 0 0/2 * * ?")
    public void testOne() {
        //每2小時執行一次緩存
        init();
    }

}

使用：
 

//從緩存中獲取城市；
        Map<String, TownNameDto> cityModelMap = CodeCache.codeMap;
        Map<String, CompanyModel> companyModelMap = CodeCache.companyMap;