Springboot 在项目启动时将数据缓存到全局变量

爱被打了一巴掌 2023-08-17 16:00 80阅读 0赞

# 声明： #

有写字典数据不会频繁更新，但是会频繁查询，想要减少数据库链接次数，把内容缓存到项目的全局变量中，提高方法查询速度

# 代码： #

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() {
            //系统启动中。。。加载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() {
            //系统运行结束
        }
    
        @Scheduled(cron = "0 0 0/2 * * ?")
        public void testOne() {
            //每2小时执行一次缓存
            init();
        }
    
    }

使用：

//从缓存中获取城市；
            Map<String, TownNameDto> cityModelMap = CodeCache.codeMap;
            Map<String, CompanyModel> companyModelMap = CodeCache.companyMap;