SpringBoot動態(tài)定時功能實現(xiàn)方案詳解

更新時間：2022年11月15日 15:20:37 作者：smileNicky

在SpringBoot項目中簡單使用定時任務，不過由于要借助cron表達式且都提前定義好放在配置文件里，不能在項目運行中動態(tài)修改任務執(zhí)行時間，實在不太靈活?，F(xiàn)在我們就來實現(xiàn)可以動態(tài)修改cron表達式的定時任務,感興趣的可以了解一下

業(yè)務場景

基于上篇程序，做了一版動態(tài)定時程序，然后發(fā)現(xiàn)這個定時程序需要在下次執(zhí)行的時候會加載新的時間，所以如果改了定時程序不能馬上觸發(fā)，所以想到一種方法，在保存定時程序的時候?qū)ron表達式傳過去，然后觸發(fā)定時程序，下面看看怎么實現(xiàn)

環(huán)境準備

開發(fā)環(huán)境

JDK 1.8
SpringBoot2.2.1
Maven 3.2+

開發(fā)工具

IntelliJ IDEA
smartGit
Navicat15

實現(xiàn)方案

基于上一版進行改進：

先根據(jù)選擇的星期生成cron表達式，保存到數(shù)據(jù)庫里，同時更改cron表達式手動觸發(fā)定時程序加載最新的cron表達式
根據(jù)保存的cron表達式規(guī)則執(zhí)行定時程序
通過CommandLineRunner設置啟動加載
加上線程池，提高線程復用率和程序性能

加上ThreadPoolTaskScheduler，支持同步和異步兩種方式：

import lombok.extern.slf4j.Slf4j;
import org.springframework.aop.interceptor.AsyncUncaughtExceptionHandler;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.scheduling.annotation.AsyncConfigurer;
import org.springframework.scheduling.annotation.EnableAsync;
import org.springframework.scheduling.annotation.EnableScheduling;
import org.springframework.scheduling.annotation.SchedulingConfigurer;
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
import org.springframework.scheduling.concurrent.ThreadPoolTaskScheduler;
import org.springframework.scheduling.config.ScheduledTaskRegistrar;
import java.util.concurrent.Executor;
import java.util.concurrent.Executors;
import java.util.concurrent.ThreadPoolExecutor;
@Configuration
@Slf4j
public class ScheduleConfig implements SchedulingConfigurer , AsyncConfigurer {
    @Override
    public void configureTasks(ScheduledTaskRegistrar taskRegistrar) {
        taskRegistrar.setScheduler(taskScheduler());
    }
    @Bean(destroyMethod="shutdown" , name = "taskScheduler")
    public ThreadPoolTaskScheduler taskScheduler() {
        ThreadPoolTaskScheduler scheduler = new ThreadPoolTaskScheduler();
        scheduler.setPoolSize(10);
        scheduler.setThreadNamePrefix("itemTask-");
        scheduler.setAwaitTerminationSeconds(600);
        scheduler.setWaitForTasksToCompleteOnShutdown(true);
        return scheduler;
    }
    @Bean(name = "asyncExecutor")
    public ThreadPoolTaskExecutor asyncExecutor() {
        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
        executor.setCorePoolSize(10);
        executor.setQueueCapacity(1000);
        executor.setKeepAliveSeconds(600);
        executor.setMaxPoolSize(20);
        executor.setThreadNamePrefix("itemAsyncTask-");
        executor.setRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy());
        executor.initialize();
        return executor;
    }
    @Override
    public Executor getAsyncExecutor() {
        return asyncExecutor();
    }
    @Override
    public AsyncUncaughtExceptionHandler getAsyncUncaughtExceptionHandler() {
        return (throwable, method, objects) -> {
            log.error("異步任務異常,message {} , method {} , params" , throwable , method , objects);
        };
    }
}

加上一個SchedulerTaskJob接口：

public interface SchedulerTaskJob{
    void executeTask();
}

AbstractScheduler 抽象類，提供基本的功能

import lombok.Data;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Configuration;
import org.springframework.scheduling.Trigger;
import org.springframework.scheduling.TriggerContext;
import org.springframework.scheduling.annotation.SchedulingConfigurer;
import org.springframework.scheduling.concurrent.ThreadPoolTaskScheduler;
import org.springframework.scheduling.config.ScheduledTaskRegistrar;
import org.springframework.scheduling.support.CronTrigger;
import org.springframework.stereotype.Component;
import javax.annotation.Resource;
import java.util.Date;
@Slf4j
@Component
@Data
public abstract class AbstractScheduler implements SchedulerTaskJob{
    @Resource(name = "taskScheduler")
    private ThreadPoolTaskScheduler threadPoolTaskScheduler;
    @Override
    public void executeTask() {
        String cron = getCronString();
        Runnable task = () -> {
            // 執(zhí)行業(yè)務
            doBusiness();
        };
        Trigger trigger = new Trigger()   {
            @Override
            public Date nextExecutionTime(TriggerContext triggerContext) {
                CronTrigger trigger;
                try {
                    trigger = new CronTrigger(cron);
                    return trigger.nextExecutionTime(triggerContext);
                } catch (Exception e) {
                    log.error("cron表達式異常，已經(jīng)啟用默認配置");
                    // 配置cron表達式異常，執(zhí)行默認的表達式
                    trigger = new CronTrigger(getDefaultCron());
                    return trigger.nextExecutionTime(triggerContext);
                }
            }
        };
        threadPoolTaskScheduler.schedule(task , trigger);
    }
    protected abstract String getCronString();
    protected abstract void doBusiness();
    protected abstract String getDefaultCron();
}

實現(xiàn)類，基于自己的業(yè)務實現(xiàn)，然后事項抽象類，通過模板模式進行編程

import cn.hutool.core.util.StrUtil;
import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.core.toolkit.Wrappers;
import lombok.Data;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Service;
import javax.annotation.Resource;
import java.time.LocalDateTime;
@Service
@Slf4j
@Data
public class ItemSyncScheduler extends AbstractScheduler {
    @Value("${configtask.default.itemsync}")
    private String defaultCron ;
    private String cronString ;
    @Override
    protected String getCronString() {
        if (StrUtil.isNotBlank(cronString))  return cronString;
        SyncConfigModel configModel = syncConfigService.getOne(Wrappers.<SyncConfigModel>lambdaQuery()
                .eq(SyncConfigModel::getBizType, 1)
                .last("limit 1"));
        if (configModel == null) return defaultCron;
        return configModel.getCronStr();
    }
    @Override
    protected void doBusiness() {
        log.info("執(zhí)行業(yè)務...");
        log.info("執(zhí)行時間:{}"  , LocalDateTime.now());
       // 執(zhí)行業(yè)務
    }
    @Override
    protected String getDefaultCron() {
        return defaultCron;
    }
}

如果更改了cron表達式，程序不會馬上觸發(fā)，所以直接開放一個接口出來，調(diào)用的時候，設置最新的表達式，然后重新調(diào)用定時程序

import io.swagger.annotations.Api;
import io.swagger.annotations.ApiOperation;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
@RestController
@Slf4j
public class ItemSchedulerController {
    private ItemSyncScheduler itemSyncScheduler;
    @Autowired
    public ItemSchedulerController(ItemSyncScheduler itemSyncScheduler) {
        this.itemSyncScheduler= itemSyncScheduler;
    }
    @GetMapping(value = "/updateItemCron")
    @ApiOperation(value = "更新cron表達式")
    public void updateItemCron(@RequestParam("cronString") String cronString) {
        log.info("更新cron表達式...");
        log.info("cronString:{}" , cronString);
        itemSyncScheduler.setCronString(cronString);
        itemSyncScheduler.executeTask();
    }
}

實現(xiàn)CommandLineRunner ，實現(xiàn)Springboot啟動加載

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;
import javax.annotation.Resource;
@Component
@Order(1)
public class SchedulerTaskRunner implements CommandLineRunner {
    private ItemSyncScheduler itemSyncScheduler;
    @Autowired
    public SchedulerTaskRunner(ItemSyncScheduler itemSyncScheduler) {
        this.itemSyncScheduler= itemSyncScheduler;
    }
    @Override
    public void run(String... args) throws Exception {
        itemSyncScheduler.executeTask();
    }
}

歸納總結(jié)

基于上一版定時程序的問題，做了改進，加上了線程池和做到了動態(tài)觸發(fā)，網(wǎng)上的資料很多都是直接寫明使用SchedulingConfigurer來實現(xiàn)動態(tài)定時程序，不過很多都寫明場景，本文通過實際，寫明實現(xiàn)方法，本文是在保存定時程序的時候，設置最新的cron表達式，調(diào)一下接口重新加載，還可以使用canal等中間件監(jiān)聽數(shù)據(jù)表，如果改了就再設置cron表達式，然后觸發(fā)程序

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