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SpringBoot程序预装载数据怎么实现

2023-06-30 11:08

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简介

在项目实际的开发过程中，有时候会遇到需要在应用程序启动完毕对外提供服务之前预先将部分数据装载到缓存的需求。

适用场景

预装载应用级别数据到缓存：如字典数据、公共的业务数据
系统预热
心跳检测：如在系统启动完毕访问一个外服务接口等场景

常用方法

ApplicationEvent
CommandLineRunner
ApplicationRunner

ApplicationEvent

应用程序事件，就是发布订阅模式。在系统启动完毕，向应用程序注册一个事件，监听者一旦监听到了事件的发布，就可以做一些业务逻辑的处理了。

既然是发布-订阅模式，那么订阅者既可以是一个，也可以是多个。

定义event

import org.springframework.context.ApplicationEvent;public class CacheEvent   extends ApplicationEvent {    public CacheEvent(Object source) {        super(source);    }}

定义listener

import lombok.extern.slf4j.Slf4j;import org.apache.commons.lang3.StringUtils;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.context.ApplicationListener;import org.springframework.stereotype.Component;import org.springframework.util.CollectionUtils;import java.util.List;import java.util.Map;import java.util.stream.Collectors;@Slf4j@Componentpublic class CacheEventListener implements ApplicationListener<CacheEvent> {    @Autowired    private MaskingService maskingService;    @Autowired    private RedisCache redisCache;    @Override    public void onApplicationEvent(CacheEvent cacheEvent) {        log.debug("CacheEventListener-start");        List<SysMasking> maskings = maskingService.selectAllSysMaskings();        if (!CollectionUtils.isEmpty(maskings)) {            log.debug("CacheEventListener-data-not-empty");            Map<String, List<SysMasking>> cacheMap = maskings.stream().collect(Collectors.groupingBy(SysMasking::getFieldKey));            cacheMap.keySet().forEach(x -> {                if (StringUtils.isNotEmpty(x)) {                    log.debug("CacheEventListener-x={}", x);                    List<SysMasking> list = cacheMap.get(x);                    long count = redisCache.setCacheList(RedisKeyPrefix.MASKING.getPrefix() + x, list);                    log.debug("CacheEventListener-count={}", count);                } else {                    log.debug("CacheEventListener-x-is-empty");                }            });        } else {            log.debug("CacheEventListener-data-is-empty");        }        log.debug("CacheEventListener-end");    }}

注册event

@Slf4j@SpringBootApplication(exclude = {DataSourceAutoConfiguration.class})public class BAMSApplication {    public static void main(String[] args) {        ConfigurableApplicationContext context = SpringApplication.run(BAMSApplication.class, args);        log.debug("app-started");        context.publishEvent(new CacheEvent("处理缓存事件"));    }}

CommandLineRunner

通过实现 CommandLineRunner 接口，可以在应用程序启动完毕，回调到指定的方法中。

package com.ramble.warmupservice.runner;import lombok.extern.slf4j.Slf4j;import org.springframework.boot.CommandLineRunner;import org.springframework.stereotype.Component;@Slf4j@Componentpublic class CacheCommandLineRunner implements CommandLineRunner {    @Override    public void run(String... args) throws Exception {        log.debug("CacheCommandLineRunner-start");        log.debug("CacheCommandLineRunner-参数={}", args);        // 注入业务 service ，获取需要缓存的数据        // 注入 redisTemplate ，将需要缓存的数据存放到 redis 中        log.debug("CacheCommandLineRunner-end");    }}

ApplicationRunner

同CommandLineRunner 类似，区别在于，对参数做了封装。

package com.ramble.warmupservice.runner;import com.alibaba.fastjson.JSON;import lombok.extern.slf4j.Slf4j;import org.springframework.boot.ApplicationArguments;import org.springframework.boot.ApplicationRunner;import org.springframework.stereotype.Component;@Slf4j@Componentpublic class CacheApplicationRunner implements ApplicationRunner {    @Override    public void run(ApplicationArguments args) throws Exception {        log.debug("CacheApplicationRunner-start");        log.debug("CacheApplicationRunner-参数={}", JSON.toJSONString(args));        // 注入业务 service ，获取需要缓存的数据        // 注入 redisTemplate ，将需要缓存的数据存放到 redis 中        log.debug("CacheApplicationRunner-end");    }}

测试

上述代码在idea中启动，若不带参数，输出如下：

2022-04-28 15:44:00.981 INFO 1160 --- [ main] c.r.w.WarmupServiceApplication : Started WarmupServiceApplication in 1.335 seconds (JVM running for 2.231)
2022-04-28 15:44:00.982 DEBUG 1160 --- [ main] c.r.w.runner.CacheApplicationRunner : CacheApplicationRunner-start
2022-04-28 15:44:01.025 DEBUG 1160 --- [ main] c.r.w.runner.CacheApplicationRunner : CacheApplicationRunner-参数={"nonOptionArgs":[],"optionNames":[],"sourceArgs":[]}
2022-04-28 15:44:01.025 DEBUG 1160 --- [ main] c.r.w.runner.CacheApplicationRunner : CacheApplicationRunner-end
2022-04-28 15:44:01.025 DEBUG 1160 --- [ main] c.r.w.runner.CacheCommandLineRunner : CacheCommandLineRunner-start
2022-04-28 15:44:01.026 DEBUG 1160 --- [ main] c.r.w.runner.CacheCommandLineRunner : CacheCommandLineRunner-参数={}
2022-04-28 15:44:01.026 DEBUG 1160 --- [ main] c.r.w.runner.CacheCommandLineRunner : CacheCommandLineRunner-end
2022-04-28 15:44:01.026 DEBUG 1160 --- [ main] c.r.w.listener.CacheEventListener : CacheEventListener-start
2022-04-28 15:44:01.026 DEBUG 1160 --- [ main] c.r.w.listener.CacheEventListener : CacheEventListener-参数=ApplicationEvent-->缓存系统数据
2022-04-28 15:44:01.029 DEBUG 1160 --- [ main] c.r.w.listener.CacheEventListener : CacheEventListener-end
Disconnected from the target VM, address: '127.0.0.1:61320', transport: 'socket'
Process finished with exit code 130

若使用 java -jar xxx.jar --server.port=9009 启动，则输入如下：

2022-04-28 16:02:05.327 INFO 9916 --- [ main] c.r.w.WarmupServiceApplication : Started WarmupServiceApplication in 1.78 seconds (JVM running for 2.116)
2022-04-28 16:02:05.329 DEBUG 9916 --- [ main] c.r.w.runner.CacheApplicationRunner : CacheApplicationRunner-start
2022-04-28 16:02:05.393 DEBUG 9916 --- [ main] c.r.w.runner.CacheApplicationRunner : CacheApplicationRunner-参数={"nonOptionArgs":[],"optionNames":["server.port"],"sourceArgs":["--server.port=9009"]}
2022-04-28 16:02:05.395 DEBUG 9916 --- [ main] c.r.w.runner.CacheApplicationRunner : CacheApplicationRunner-end
2022-04-28 16:02:05.395 DEBUG 9916 --- [ main] c.r.w.runner.CacheCommandLineRunner : CacheCommandLineRunner-start
2022-04-28 16:02:05.395 DEBUG 9916 --- [ main] c.r.w.runner.CacheCommandLineRunner : CacheCommandLineRunner-参数=--server.port=9009
2022-04-28 16:02:05.395 DEBUG 9916 --- [ main] c.r.w.runner.CacheCommandLineRunner : CacheCommandLineRunner-end
2022-04-28 16:02:05.395 DEBUG 9916 --- [ main] c.r.w.listener.CacheEventListener : CacheEventListener-start
2022-04-28 16:02:05.396 DEBUG 9916 --- [ main] c.r.w.listener.CacheEventListener : CacheEventListener- 参数=ApplicationEvent-->缓存系统数据
2022-04-28 16:02:05.396 DEBUG 9916 --- [ main] c.r.w.listener.CacheEventListener : CacheEventListener-end