基于SpringBoot的轻量、非侵入式数据库数据告警工具

傍晚时分，你坐在屋檐下，看着天慢慢地黑下去，心里寂寞而凄凉，感到自己的生命被剥夺了。当时我是个年轻人，但我害怕这样生活下去，衰老下去。在我看来，这是比死亡更可怕的事。——–王小波

基于SpringBoot的轻量、非侵入式数据库数据告警器

傍晚时分，你坐在屋檐下，看着天慢慢地黑下去，心里寂寞而凄凉，感到自己的生命被剥夺了。当时我是个年轻人，但我害怕这样生活下去，衰老下去。在我看来，这是比死亡更可怕的事。——–王小波

我的需求：

需要写一个数据库数据监控的告警小工具，要求：

• 非侵入式的，对监控的数据只有查询权限，没有写权限
• 可以对数据表的部分数据状态，数据数量进行监控告警
• 监控数据，告警条件等是可配置的

我需要解决的问题：

• 抽象告警行为，解耦告警流程构建过程
• 告警命中之后如何避免重复告警
• 可配置的部分如何从流程代码中解耦为配置
• 如何动态配置告警扫描计划

我是这样做的：

---

整体来讲，逻辑很简单，没啥技术难点，属于重复造轮子，考虑到需要解析配置文件、多数据源配置，定时任务等，所以使用SpringBoot，利用其自动化配置,类型安全配置属性，集成简单的任务调度等优点,可以方便地的配置不同的数据源，同时将复杂配置文件中的数据注入Bean中，动态配置定时计划

关于多数据源配置和类型安全配置属性等不是本文重点，这里不多讲。

编码思路：

• 一是解耦告警器类的构建和构建步骤
• 二是解耦告警流程，涉及的单个行为从流程解耦，对于行为可变的部分从代码解耦为配置文件。
• 三是对于告警缓存的处理，非侵入式需要解决重复告警，当前集成了H2，但是没有使用，感觉有点重，所以利用WeakHashMap构建了一个弱键的缓存工具类来实现。

解耦告警器类的构建和构建步骤

对于告警器类的构建，涉及初始化和告警规则生成两部分，初始化负责告警配置文件加载解析校验，告警规则生成负责告警流程的建立。

这里可以使用默认的初始化规则，和告警解析规程,也可以使用自定义的规则。整体上编码基于构建者设计模式，类似于Spring Security配置对象的构建

可以使用默认的告警解析流程，调用方式

alarms.alarmStart()

alarms.alarmsInit(null).alarmsRun(null);

也可以通过自定义告警解析流程，这里采用函数式编程的思想，通过行为参数化的方式，可以动态编写告警解析流程。

// 告警器初始化
 alarms.alarmsInit(alarmsInit -> {
                logger.info("告警器扫描时间周期cron:" + alarmsInit.getMinute());
                alarmsInit.getAlarms().forEach((alarm -> {
                    logger.info("加载的告警器名称：" + alarm.getItemsName());
                    logger.info("触发器：" + alarm.getTrigger());
                    logger.info("动作：" + Arrays.toString(alarm.getActions()));
                    logger.info("告警媒介：" + Arrays.toString(alarm.getMediaType()));
                    logger.info("告警内容：" + alarm.getMedia());
                    logger.info("告警短信插表SQL：" + alarm.getMediaSql());
                }));
                return alarmsInit;
            // 告警规则生成
            }).alarmsRun(alarmsRun -> {
                logger.info("告警器扫描......");
                alarmsRun.getAlarms().forEach(alarm -> {
                    Boolean boo = Long.class.cast(jdbcTemplateOne.queryForList(alarm.getTrigger()).get(0).get("isAlarms")) == 1L ? Boolean.TRUE : Boolean.FALSE;
                    if (boo) {
                        logger.info("告警规则命中......" + alarm.getTrigger());

Arrays.stream(alarm.getActions()).forEach(sql -> {
                            List<Map<String, Object>> list = jdbcTemplateOne.queryForList(sql);
                            Object[] codes = list.stream().map((code) -> code.get("code").toString()).toArray();
                            Arrays.stream(alarm.getMediaType()).forEach(phone -> {

String msg = String.format(alarm.getMedia(), Arrays.toString(codes));

logger.info("告警消息生产......》》》》 content：" + msg + " phone:" + phone);

Object oldTime = cache.get(msg + phone);

if (Objects.isNull(oldTime)) {
                                    cache.put(msg + phone, System.currentTimeMillis());
                                    jdbcTemplateTow.execute(String.format(alarm.getMediaSql(), msg, phone, phone));
                                } else {
                                    if (System.currentTimeMillis() - Long.class.cast(oldTime) > 7200000L) {
                                        jdbcTemplateTow.execute(String.format(alarm.getMediaSql(), msg, phone, phone));
                                        cache.put(msg + phone, System.currentTimeMillis());
                                    } else {
                                        logger.info("2小时内重复告警消息....不发送");
                                    }
                                }
                            });
                        });
                    }
                });
                return alarmsRun;
            });

解耦告警行为和流程

关于告警流程，这里结合zabbix监控告警的配置方式，抽象出触发器，动作，告警媒介,告警消息模板,插表sql等行为，整个告警流程行为通过配置文件配置，在上面告警器构建中告警规则生成中整合行为成完成流程。

• 触发器(trigger)：这里的触发器是一个返回0/1布尔值的SQL,当为true时人为告警被触发，会执行动作。
• 动作(actions[])：动作在这里是一组返回触发告警标识内容的SQL，用于描述告警触发后的行为,返回触发告警的数据
• 告警媒介(mediaType[])： 当前告警通过短信的方式，所以这里是一组电话号码，要给哪些用户发生告警消息
• 告警消息模板(media)：不多讲，结合上面动作获取的告警数据，生成完整告警消息
• 插表sql(mediaSql)： 当前发送短信的方式通过插表的方式，如何通过邮件或则短信发生调API的方式,就需要自定义告警规则

我们通配置文件看几个具体的场景

活动监控场景：适用一些批量处理任务的数据，通过where条件判断是否有不符合预期状态的数据，有则获取这部分数据的唯一标识，生成告警消息发送。

空表校验场景： 适用一些账期表，在某些时间会数据落表，通过where条件判断是否存在数据，没有则通过select 'XXX 表数据为空' as code 的方式构建告警消息，发生告警讯息

大表监控场景： 适用部分大表在数据量达到某个峰值的时候，会影响系统性能、SQL超时甚至部分持久化数据丢失，需要对冗余数据进行备份清理。需要提前告警.

alarms:
  minute: "*/5 * * * * ?"
  alarms:
      # 告警策略名称
    - itemsName: "活动监控 "
      #  SQL return isAlarms is Boolean 触发器
      trigger: "select count(*) > 0 as isAlarms from 活动表  a WHERE a.CREATED_DATE >  SUBDATE(NOW(),interval 1 day)  AND a.CREATED_DATE < SUBDATE(NOW(), interval 1 hour)  AND a.STATE ='A' AND a.SP_ID=0"
      # SQL return code is String[], 动作
      actions: [ "select  ACTIVITY_CODE as code from 活动表  a WHERE a.CREATED_DATE >  SUBDATE(NOW(),interval 1 day)  AND a.CREATED_DATE < SUBDATE(NOW(), interval 1 hour)  AND a.STATE ='A' AND a.SP_ID=0" ]
      #  MMS is String[] 告警媒介
      mediaType: [ "18147405370","13147405370","12147405370"]
      # MMS content 告警消息
      media: "%s 活动发生异常，请排查"
      #  MMS install SQL 插表sql
      mediaSql: "INSERT INTO 短信表 (MT_SEQ,  MT_SERV_TYPE, SEND_PRIORITY,  MSG_CONTENT, DEST_TERMID, SRC_TERMID, FEE_USER_TERMID,  FEE_TYPE,   MAKE_TIME,  REQUIRE_APPLY ) VALUES (sms.ACCT_SENDSMS_SEQ.NEXTVAL,'123',2,'%s', '%s','1183111', '%s', '00',SYSDATE,0)"
   - itemsName: "XXX 空表校验"
     trigger: "select count(*) = 0 as isAlarms from XXX"
     actions: ["select 'XXX 表数据为空' as code "]
     mediaType: ['123123','3123']
     media: "%s 异常信息，请排查"
     mediaSql: "insert into sms(phone,content) values('%s','%s')"
   - itemsName: "XXX 大表监控"
     trigger: "select count(*) > 40000000 as isAlarms from XXX"
     actions: ["select 'XXX 表数据量超过峰值' as code "]
     mediaType: ['123123','3123']
     media: "%s 异常信息，请排查"
     mediaSql: "insert into sms(phone,content) values('%s','%s')"  

重复告警的问题

关于重复告警的问题，集成了H2，但是目前告警数据量小，所以没有使用，对于重复告警使用了WeakHashMap构建了一个弱键的缓存工具类实现。

第一告警触发后，存到缓存里，之后2小时内触发告警不发送告警消息，2小时候在发送一次

Object oldTime = cache.get(msg + phone);

if (Objects.isNull(oldTime)) {
    cache.put(msg + phone, System.currentTimeMillis());
    jdbcTemplateTow.execute(String.format(alarm.getMediaSql(), msg, phone,phone));
} else {
    if (System.currentTimeMillis() -Long.class.cast(oldTime) > 7200000L){
        jdbcTemplateTow.execute(String.format(alarm.getMediaSql(), msg, phone,phone));
        cache.put(msg + phone, System.currentTimeMillis());
    }else {
        logger.info("2小时内重复告警消息....不发送");
    }
}

动态定时任务配置

通过SchedulingConfigurer配置类实现动态配置，重配置文件获取cron表达式

DynamicCronSchedule.java

package com.example.alarms.alert;

import com.example.alarms.alert.dto.Alarms;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.scheduling.annotation.EnableScheduling;
import org.springframework.scheduling.annotation.SchedulingConfigurer;
import org.springframework.scheduling.config.ScheduledTaskRegistrar;
import org.springframework.scheduling.support.CronTrigger;
import org.springframework.stereotype.Component;

import java.util.*;
import java.util.logging.Logger;

/**
 * @author LiRuilong
 * @Classname DynamicCronSchedule
 * @Description TODO
 * @Date 2022/5/16 11:31
 */
@Component
@EnableScheduling
public class DynamicCronSchedule implements SchedulingConfigurer {
    private static Logger logger = Logger.getLogger("com.example.alarms.alert.DynamicCronSchedule");

@Autowired
    private Alarms alarms;


    @Override
    public void configureTasks(ScheduledTaskRegistrar taskRegistrar) {

alarms.alarmsInit(null);

taskRegistrar.addTriggerTask(() -> {

// 自定义逻辑：
            //alarms.alarmsRun(alarmsRun -> alarmsRun);

// 默认逻辑：
            alarms.alarmsRun(null);

}, (triggerContext) -> {
            String cron = alarms.getMinute();

logger.fine("cron expression is " + cron);
            logger.fine("trigger list size is " + taskRegistrar.getTriggerTaskList().size());


            CronTrigger cronTrigger = new CronTrigger(cron);
            Date nextExecTime = cronTrigger.nextExecutionTime(triggerContext);
            return nextExecTime;
        });


    }
}

---
server:
  port: 30036
  tomcat:
    uri-encoding: utf-8

spring:
  datasource:
    one:
      type: com.alibaba.druid.pool.DruidDataSource
      driver-class-name: com.mysql.jdbc.Driver
      username: 
      password: 
      url: 
      test-while-idle: true

tow:
      driver-class-name: oracle.jdbc.OracleDriver
      username: 
      password: 
      url: 
      test-while-idle: true
    h2db:
      type: com.alibaba.druid.pool.DruidDataSource
      driver-class-name: org.h2.Driver
      schema: classpath:db/schema.sql
      username: sa
      password: sa
      url: jdbc:h2:mem:alarms


  #http://本地端口/h2-console 通过项目来进行访问数据库
  h2:
    console:
      enabled: true


alarms:
  minute: "*/5 * * * * ?"
  alarms:
      # 告警策略名称
    - itemsName: "活动监控 "
      #  SQL return isAlarms is Boolean 触发器
      trigger: "select count(*) > 0 as isAlarms from 活动表  a WHERE a.CREATED_DATE >  SUBDATE(NOW(),interval 1 day)  AND a.CREATED_DATE < SUBDATE(NOW(), interval 1 hour)  AND a.STATE ='A' AND a.SP_ID=0"
      # SQL return code is String[], 动作
      actions: [ "select  ACTIVITY_CODE as code from 活动表  a WHERE a.CREATED_DATE >  SUBDATE(NOW(),interval 1 day)  AND a.CREATED_DATE < SUBDATE(NOW(), interval 1 hour)  AND a.STATE ='A' AND a.SP_ID=0" ]
      #  MMS is String[] 告警媒介
      mediaType: [ "18147405370","13147405370","12147405370"]
      # MMS content 告警消息
      media: "%s 活动发生异常，请排查"
      #  MMS install SQL 插表sql
      mediaSql: "INSERT INTO 短信表 (MT_SEQ,  MT_SERV_TYPE, SEND_PRIORITY,  MSG_CONTENT, DEST_TERMID, SRC_TERMID, FEE_USER_TERMID,  FEE_TYPE,   MAKE_TIME,  REQUIRE_APPLY ) VALUES (sms.ACCT_SENDSMS_SEQ.NEXTVAL,'123',2,'%s', '%s','1183111', '%s', '00',SYSDATE,0)"
   - itemsName: "XXX 空表校验"
     trigger: "select count(*) = 0 as isAlarms from XXX"
     actions: ["select 'XXX 表数据为空' as code "]
     mediaType: ['123123','3123']
     media: "%s 异常信息，请排查"
     mediaSql: "insert into sms(phone,content) values('%s','%s')"
   - itemsName: "XXX 大表监控"
     trigger: "select count(*) > 40000000 as isAlarms from XXX"
     actions: ["select 'XXX 表数据量超过峰值' as code "]
     mediaType: ['123123','3123']
     media: "%s 异常信息，请排查"
     mediaSql: "insert into sms(phone,content) values('%s','%s')" 

package com.example.alarms.alert.config;

import com.alibaba.druid.spring.boot.autoconfigure.DruidDataSourceBuilder;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import javax.sql.DataSource;

/**
 * @author LiRuilong
 * @Classname DataSourceConfig
 * @Description TODO
 * @Date 2022/5/10 9:59
 */

@Configuration
public class DataSourceConfig {


    @Bean
    @ConfigurationProperties("spring.datasource.one")
    DataSource dsOne() {
        return DruidDataSourceBuilder.create().build();
    }

@Bean
    @ConfigurationProperties("spring.datasource.tow")
    DataSource dsTow() {
        return DruidDataSourceBuilder.create().build();
    }

@Bean
    @ConfigurationProperties("spring.datasource.h2db")
    DataSource dsH2db() {
        return DruidDataSourceBuilder.create().build();
    }

}

package com.example.alarms.alert.config;

import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.jdbc.core.JdbcTemplate;

import javax.sql.DataSource;

/**
 * @author LiRuilong
 * @Classname JdbcTemplateConfig
 * @Description TODO
 * @Date 2022/5/10 10:01
 */

@Configuration
public class JdbcTemplateConfig {


    @Bean
    JdbcTemplate jdbcTemplateOne(@Qualifier("dsOne") DataSource ds) {
        return new JdbcTemplate(ds);
    }

@Bean
    JdbcTemplate jdbcTemplateTow(@Qualifier("dsTow") DataSource ds) {
        return new JdbcTemplate(ds);
    }

@Bean
    JdbcTemplate jdbcTemplateH2db(@Qualifier("dsH2db") DataSource ds) {
        return new JdbcTemplate(ds);
    }


}

package com.example.alarms.alert;

import com.example.alarms.alert.dto.Alarms;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.scheduling.annotation.EnableScheduling;
import org.springframework.scheduling.annotation.SchedulingConfigurer;
import org.springframework.scheduling.config.ScheduledTaskRegistrar;
import org.springframework.scheduling.support.CronTrigger;
import org.springframework.stereotype.Component;

import java.util.*;
import java.util.logging.Logger;

/**
 * @author LiRuilong
 * @Classname DynamicCronSchedule
 * @Description TODO
 * @Date 2022/5/16 11:31
 */
@Component
@EnableScheduling
public class DynamicCronSchedule implements SchedulingConfigurer {
    private static Logger logger = Logger.getLogger("com.example.alarms.alert.DynamicCronSchedule");

@Autowired
    private Alarms alarms;


    @Override
    public void configureTasks(ScheduledTaskRegistrar taskRegistrar) {

alarms.alarmsInit(null);

taskRegistrar.addTriggerTask(() -> {

// 自定义逻辑：
            //alarms.alarmsRun(alarmsRun -> alarmsRun);

// 默认逻辑：
            alarms.alarmsRun(null);

}, (triggerContext) -> {
            String cron = alarms.getMinute();

logger.fine("cron expression is " + cron);
            logger.fine("trigger list size is " + taskRegistrar.getTriggerTaskList().size());


            CronTrigger cronTrigger = new CronTrigger(cron);
            Date nextExecTime = cronTrigger.nextExecutionTime(triggerContext);
            return nextExecTime;
        });


    }
}

告警bean相关

package com.example.alarms.alert.dto;

import java.io.Serializable;
import java.util.Arrays;

/**
 * @Classname Alarm
 * @Description TODO
 * @Date 2022/5/13 18:12
 * @Created LiRuilong
 */
public class Alarm  implements Serializable {


    private  String itemsName;

private  String trigger;

private  String[] actions;

private  String[] mediaType;

private  String media;

private  String mediaSql;


    public String getItemsName() {
        return itemsName;
    }

public Alarm setItemsName(String itemsName) {
        this.itemsName = itemsName;
        return this;
    }

public String[] getActions() {
        return actions;
    }

public Alarm setActions(String[] actions) {
        this.actions = actions;
        return this;
    }

public String getTrigger() {
        return trigger;
    }

public Alarm setTrigger(String trigger) {
        this.trigger = trigger;
        return this;
    }

public String[] getMediaType() {
        return mediaType;
    }

public Alarm setMediaType(String[] mediaType) {
        this.mediaType = mediaType;
        return this;
    }

public String getMedia() {
        return media;
    }

public Alarm setMedia(String media) {
        this.media = media;
        return this;
    }

public String getMediaSql() {
        return mediaSql;
    }

public Alarm setMediaSql(String mediaSql) {
        this.mediaSql = mediaSql;
        return this;
    }

@Override
    public String toString() {
        return "Alarm{" +
                "itemsName='" + itemsName + '\'' +
                ", actions=" + Arrays.toString(actions) +
                ", trigger='" + trigger + '\'' +
                ", mediaType=" + Arrays.toString(mediaType) +
                ", media='" + media + '\'' +
                ", mediaSql='" + mediaSql + '\'' +
                '}';
    }
}

package com.example.alarms.alert.dto;

import com.example.alarms.alert.WeakHashMapCache;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Component;

import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.function.Function;
import java.util.logging.Logger;

/**
 * @author LiRuilong
 * @Classname Alarms
 * @Description TODO
 * @Date 2022/5/13 17:23
 */

@Component
@ConfigurationProperties(prefix = "alarms")
public class Alarms {

Logger logger = Logger.getLogger("com.example.alarms.alert.dto.Alarms");


    WeakHashMapCache cache = new WeakHashMapCache.Builder<String, String>(1000).build();

private String minute;


    private List<Alarm> alarms;


    @Autowired
    @Qualifier("jdbcTemplateOne")
    JdbcTemplate jdbcTemplateOne;


    @Autowired
    @Qualifier("jdbcTemplateTow")
    JdbcTemplate jdbcTemplateTow;


    public String getMinute() {
        return minute;
    }

public Alarms setMinute(String minute) {
        this.minute = minute;
        return this;
    }

public List<Alarm> getAlarms() {
        return alarms;
    }

public Alarms setAlarms(List<Alarm> alarms) {
        this.alarms = alarms;
        return this;
    }

/**
     * @param function:
     * @return: com.example.alarms.alert.dto.Alarms
     * @Description 告警数据加载，默认逻辑
     * @author LiRuilong
     * @date 2022/5/16  11:12
     **/
    public Alarms alarmsInit(Function<Alarms, Alarms> function) {

if (Objects.nonNull(function)) {
            return function.apply(this);
        } else {
            logger.info("告警器扫描时间周期cron:" + this.getMinute());
            alarms.forEach((alarm -> {
                logger.info("加载的告警器名称：" + alarm.getItemsName());
                logger.info("触发器：" + alarm.getTrigger());
                logger.info("动作：" + Arrays.toString(alarm.getActions()));
                logger.info("告警媒介：" + Arrays.toString(alarm.getMediaType()));
                logger.info("告警内容：" + alarm.getMedia());
                logger.info("告警短信插表SQL：" + alarm.getMediaSql());
            }));
            return this;
        }
    }

/**
     * @param function:
     * @return: com.example.alarms.alert.dto.Alarms
     * @Description 告警器执行，默认逻辑
     * @author LiRuilong
     * @date 2022/5/16  11:30
     **/
    public Alarms alarmsRun(Function<Alarms, Alarms> function) {

if (Objects.nonNull(function)) {
            return function.apply(this);
        } else {
            logger.info("告警器扫描......");
            alarms.forEach(alarm -> {
                Boolean boo = Long.class.cast(jdbcTemplateOne.queryForList(alarm.getTrigger()).get(0).get("isAlarms")) == 1L ? Boolean.TRUE : Boolean.FALSE;
                if (boo) {
                    logger.info("告警规则命中......" + alarm.getTrigger());

Arrays.stream(alarm.getActions()).forEach(sql -> {
                        List<Map<String, Object>> list = jdbcTemplateOne.queryForList(sql);
                        Object[] codes = list.stream().map((code) -> code.get("code").toString()).toArray();
                        Arrays.stream(alarm.getMediaType()).forEach(phone -> {

String msg = String.format(alarm.getMedia(), Arrays.toString(codes));

logger.info("告警消息生产......》》》》 content：" + msg + " phone:" + phone);

Object oldTime = cache.get(msg + phone);

if (Objects.isNull(oldTime)) {
                                cache.put(msg + phone, System.currentTimeMillis());
                                jdbcTemplateTow.execute(String.format(alarm.getMediaSql(), msg, phone,phone));
                            } else {
                                if (System.currentTimeMillis() -Long.class.cast(oldTime) > 7200000L){
                                    jdbcTemplateTow.execute(String.format(alarm.getMediaSql(), msg, phone,phone));
                                    cache.put(msg + phone, System.currentTimeMillis());
                                }else {
                                    logger.info("2小时内重复告警消息....不发送");
                                }
                            }

});

});
                }

});
            return this;
        }
    }


    public void alarmStart() {
        alarmsInit(null).alarmsRun(null);
    }

public static void main(String[] args) {

}

}

动态定时任务配置

package com.example.alarms.alert;

import com.example.alarms.alert.dto.Alarms;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.scheduling.annotation.EnableScheduling;
import org.springframework.scheduling.annotation.SchedulingConfigurer;
import org.springframework.scheduling.config.ScheduledTaskRegistrar;
import org.springframework.scheduling.support.CronTrigger;
import org.springframework.stereotype.Component;

import java.util.*;
import java.util.logging.Logger;

/**
 * @author LiRuilong
 * @Classname DynamicCronSchedule
 * @Description TODO
 * @Date 2022/5/16 11:31
 */
@Component
@EnableScheduling
public class DynamicCronSchedule implements SchedulingConfigurer {
    private static Logger logger = Logger.getLogger("com.example.alarms.alert.DynamicCronSchedule");

@Autowired
    private Alarms alarms;


    @Override
    public void configureTasks(ScheduledTaskRegistrar taskRegistrar) {

alarms.alarmsInit(null);

taskRegistrar.addTriggerTask(() -> {

// 自定义逻辑：
            //alarms.alarmsRun(alarmsRun -> alarmsRun);

// 默认逻辑：
            alarms.alarmsRun(null);

}, (triggerContext) -> {
            String cron = alarms.getMinute();

logger.fine("cron expression is " + cron);
            logger.fine("trigger list size is " + taskRegistrar.getTriggerTaskList().size());


            CronTrigger cronTrigger = new CronTrigger(cron);
            Date nextExecTime = cronTrigger.nextExecutionTime(triggerContext);
            return nextExecTime;
        });


    }
}

package com.example.alarms;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.scheduling.annotation.EnableScheduling;


/**
 * @Description
 * @author LiRuilong
 * @date  2022/5/13  17:22
 **/
@EnableScheduling
@SpringBootApplication
public class AlarmsApplication {


    public static void main(String[] args) {
        SpringApplication.run(AlarmsApplication.class, args);

}

}

package com.example.alarms.alert;

import java.util.Map;
import java.util.Objects;
import java.util.WeakHashMap;
import java.util.concurrent.ConcurrentHashMap;

/**
 * @Classname ConcurrentCache
 * @Description TODO 一个基于WeakHashMap本地缓存(LRU)类
 * @Date 2022/5/16 17:18
 * @author  LiRuilong
 */

public class WeakHashMapCache<K,V> {
    private final int size;

private final Map<K,V> eden;

private final Map<K,V> longterm;

private WeakHashMapCache(Builder<K,V> builder){
        this.size = builder.size;
        this.eden = builder.eden;
        this.longterm = builder.longterm;
    }

public  static class Builder<K,V>{
        private volatile int size;

private volatile  Map<K,V> eden;

private volatile Map<K,V> longterm;

public  Builder(int size){
            this.size = rangeCheck(size,Integer.MAX_VALUE,"缓存容器初始化容量异常");
            this.eden = new ConcurrentHashMap<>(size);
            this.longterm = new WeakHashMap<>(size);
        }

private static int rangeCheck(int val, int i, String arg) {
            if (val < 0 || val > i) {
                throw new IllegalArgumentException(arg + ":" + val);
            }
            return  val;
        }
        public WeakHashMapCache build(){
            return new WeakHashMapCache(this);
        }

}

public V get(K k){
        V v = this.eden.get(k);
        if (Objects.isNull(v)){
            v = this.longterm.get(k);
            if (Objects.nonNull(v)){
                this.eden.put(k,v);
            }
        }
        return v;
    }

public void put(K k,V v){
        if (this.eden.size() >= size){
            this.longterm.putAll(this.eden);
            this.eden.clear();
        }
        this.eden.put(k,v);
    }

public static void main(String[] args) {
        WeakHashMapCache cache = new WeakHashMapCache.Builder<String,String>(4).build();

for (int i = 0; i < 5; i++) {
            cache.put(i+"",i+"");
        }
        System.gc();
        for (int i = 0; i < 5; i++) {
            System.out.println(cache.get(i + ""));
        }
    }

}