叢集環境下，機器會有多個，需要執行某個或者多個機器執行後臺任務，否則可能會一個數據多個機器同時處理導致bug。這在實際工作中很常見。最近專案中也有類似需求，下面是一種實現方式，供大家參考。

使用 @Conditional 註解，判斷是本機ip才載入對應的任務的service，非配置的ip的機器則不會載入到spring容器。

IP判斷類

package cn.xiaowenjie.iptask;

import lombok.SneakyThrows;
import lombok.extern.slf4j.Slf4j;
import org.springframework.context.annotation.Condition;
import org.springframework.context.annotation.ConditionContext;
import org.springframework.core.type.AnnotatedTypeMetadata;

import java.net.InetAddress;

/**
 * 判斷是否為本機ip
 *
 * @author 曉風輕
 */
@Slf4j
public class IPCondition implements Condition {

    @Override
    public boolean matches(ConditionContext conditionContext, AnnotatedTypeMetadata annotatedTypeMetadata) {
        String runTaskIP = conditionContext.getEnvironment().getProperty("run.task.ip");
        String localIP = this.getLocalIP();

        log.info("local ip: {} , run Task IP: {}" ,localIP , runTaskIP);

        return runTaskIP.equals(localIP);
    }

    @SneakyThrows
    public String getLocalIP(){
        InetAddress address = InetAddress.getLocalHost();
        return address.getHostAddress();
    }
}
 

後臺任務類

package cn.xiaowenjie.iptask;


import lombok.extern.slf4j.Slf4j;
import org.springframework.context.annotation.Conditional;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Service;

import javax.annotation.PostConstruct;

/**
 * 後臺定時任務
 *
 * @author 曉風輕
 */
@Service
@Slf4j
@Conditional(IPCondition.class)
public class BackService {

    @PostConstruct
    public void init(){
        log.info("i run task...");
    }

    @Scheduled(cron = "0/10 * * * * *")
    public void scheduleTask(){
        log.info("task running....");
    }
}
 

實際效果

[           main] cn.xiaowenjie.iptask.IPCondition         : local ip: 192.168.1.101 , run Task IP: 192.168.1.101
[           main] cn.xiaowenjie.iptask.IPCondition         : local ip: 192.168.1.101 , run Task IP: 192.168.1.101
[           main] cn.xiaowenjie.iptask.IPCondition         : local ip: 192.168.1.101 , run Task IP: 192.168.1.101
[           main] cn.xiaowenjie.iptask.BackService         : i run task...
[           main] o.s.s.c.ThreadPoolTaskScheduler          : Initializing ExecutorService 'taskScheduler'
[           main] cn.xiaowenjie.iptask.IptaskApplication   : Started IptaskApplication in 1.364 seconds (JVM running for 2.098)
[   scheduling-1] cn.xiaowenjie.iptask.BackService         : task running....
[   scheduling-1] cn.xiaowenjie.iptask.BackService         : task running....
[   scheduling-1] cn.xiaowenjie.iptask.BackService         : task running....
[   scheduling-1] cn.xiaowenjie.iptask.BackService         : task running....
 

程式碼下載