Java--高效的定時任務設計，Java--任務設計

Java--高效的定時任務設計，Java--任務設計

相信你在日常的開發中肯定遇到過這種問題: 需要對實體類的狀態資訊進行管理,比如一定時間後修改它為XXX狀態.

舉個例子: 訂單服務,當使用者提交了訂單後,如果在30分鐘內沒有支付,自動取消訂單,這就是一個對狀態的管理;

再舉一個我實際開發的例子: 訊息管道的例子,使用者來拉取訊息後,如果在30s內沒有提交,那麼修改他的訂閱狀態為:未訂閱,這樣其他的執行個體可以建立串連繼續讀取.

 整理設計圖:

核心就是: 一個Thread + 一個Queue;Thread不斷從隊列中取出資料, 如果隊列中為空白或者裡邊的任務沒到期,則線程卡住wait(timeOut).

二 詳細設計

先是簡單的有狀態的實體類:ConsumerInfoState,這個類的核心是狀態(訂閱到期時間),所以得有對狀態的查詢設定,查詢距到期還要多久等等....

import java.io.Serializable;public class ConsumerInfoState implements Serializable {    /**     * 序列化ID     */    private static final long serialVersionUID = 1L;    /**     * 到期時間20s     */    protected long expiration;    private String topic;    private String userId;    private boolean isSubscribed = false;    private long CONSUMER_INSTANCE_TIMEOUT_MS_DEFAULT = 5000;    public ConsumerInfoState(String userId) {        this.userId = userId;        this.expiration = System.currentTimeMillis() + CONSUMER_INSTANCE_TIMEOUT_MS_DEFAULT;    }    public ConsumerInfoState(String topic, String userId) {        super();        this.topic = topic;        this.userId = userId;        this.expiration = System.currentTimeMillis() + CONSUMER_INSTANCE_TIMEOUT_MS_DEFAULT;    }   /**    *是否到期    */    public boolean expired(long nowMs) {        return expiration <= nowMs;    }    /**     * <p>     * 更新訂閱到期時間     * </p>     */    public void updateExpiration() {        this.expiration = System.currentTimeMillis() + CONSUMER_INSTANCE_TIMEOUT_MS_DEFAULT;    }    /**     * <p>     * 到指定時間還有多久     * </p>     */    public long untilExpiration(long nowMs) {        return this.expiration - nowMs;    }          public String getUserId() {        return userId;    }    public String getTopic() {        return topic;    }    public void setTopic(String topic) {        this.topic = topic;    }        public void setSubscribed(boolean isSubscribed) {        this.isSubscribed = isSubscribed;    }    public boolean hasSubscribed() {        return isSubscribed;    } }

這個類還是很清晰的..

核心類: ConsumerInfoManager

import java.util.Comparator;import java.util.PriorityQueue;import java.util.concurrent.CountDownLatch;import java.util.concurrent.atomic.AtomicBoolean;import org.slf4j.Logger;import org.slf4j.LoggerFactory;public class ConsumerInfoManager {    Logger logger = LoggerFactory.getLogger(ConsumerInfoManager.class);    //任務隊列    private final PriorityQueue<ConsumerInfoState> consumersByExpiration = new PriorityQueue<ConsumerInfoState>(            new Comparator<ConsumerInfoState>() {                //小的在前public int compare(ConsumerInfoState o1, ConsumerInfoState o2) { if (o1.expiration < o2.expiration) {                        return -1;                    } else if (o1.expiration == o2.expiration) {                        return 0;                    } else {                        return 1;                    }}});         private ExpirationThread expirationThread;        public ConsumerInfoManager() {        //啟動線程        this.expirationThread = new ExpirationThread();        this.expirationThread.start();    }    //加入任務隊列    public synchronized void addConsumerInfoSate(ConsumerInfoState consumerInfoSate) {        consumersByExpiration.add(consumerInfoSate);        this.notifyAll();    }         @SuppressWarnings("unused")    public synchronized void updateExpiration(ConsumerInfoState state) {        // 先刪除在放裡邊,重新排序        consumersByExpiration.remove(state);        state.updateExpiration();        consumersByExpiration.add(state);        this.notifyAll();    }     public void shutdown() {        logger.debug("Shutting down consumers");        expirationThread.shutdown();        synchronized (this) {            consumersByExpiration.clear();        }    }    /**     * <p>     * 檢查consumerInfo的到期時間,到期就從緩衝中刪除     * </p>     * @author jiangyuechao 2018年1月13日 下午2:04:30     */    @SuppressWarnings("unused")    private class ExpirationThread extends Thread {        AtomicBoolean isRunning = new AtomicBoolean(true);        CountDownLatch shutdownLatch = new CountDownLatch(1);        public ExpirationThread() {            super("Consumer Expiration Thread");            setDaemon(true);        }        @Override        public void run() {            synchronized (ConsumerInfoManager.this) {                try {                    while (isRunning.get()) {                        long now = System.currentTimeMillis();                        //隊列空和最近一個任務是否到期的判斷                        while (!consumersByExpiration.isEmpty() && consumersByExpiration.peek().expired(now)) {                            final ConsumerInfoState state = consumersByExpiration.remove();                            //{你自己的業務處理}                            state.setSubscribed(false);                            logger.info("任務已到期,topic:{}, userID:{},subscribed:{}",state.getTopic(),state.getUserId(),state.hasSubscribed());                        }                        //需要等待的時間                        long timeout = consumersByExpiration.isEmpty() ? Long.MAX_VALUE                                : consumersByExpiration.peek().untilExpiration(now);                        ConsumerInfoManager.this.wait(timeout);                    }                } catch (InterruptedException e) {                    // Interrupted by other thread, do nothing to allow this thread to exit                    logger.error("ExpirationThread線程中斷", e);                }            }            shutdownLatch.countDown();        }        public void shutdown() {            try {                isRunning.set(false);                this.interrupt();                shutdownLatch.await();            } catch (InterruptedException e) {                throw new Error("Interrupted when shutting down consumer worker thread.");            }        }    }    public void join(){    try {expirationThread.join();} catch (InterruptedException e) {// TODO Auto-generated catch blocke.printStackTrace();}    }}

代碼就這些,我進行了刪減,刪除了不重要的部分, 一般ConsumerInfoManager還需要一個緩衝Cache,Cache中是儲存所有的實體類,queue中是Cache中的一部分,一般queue中的任務到期,需要從Cache中刪除或取出執行一些操作.

當然加Cache是複雜點的,核心思想就這些,額外的代碼就刪除了..

最後測試一下

public class ManagerTest {static ConsumerInfoManager consumerInfoManager;static String userId = "dhsajkdsajkdsjh1";static Logger logger = LoggerFactory.getLogger(ManagerTest.class);public static void main(String[] args) throws InterruptedException {//執行個體化setUp();for(int i = 0;i<3;i++){ConsumerInfoState consumerInfoState = new ConsumerInfoState("chao-"+i, userId);consumerInfoState.setSubscribed(true);consumerInfoManager.addConsumerInfoSate(consumerInfoState);logger.info("任務"+i+"排入佇列");Thread.sleep(1000);}consumerInfoManager.join();}public static void setUp(){consumerInfoManager = new ConsumerInfoManager();}}

輸出結果: 符合預期...

2018-01-17 10:07:27,450 [main] INFO ManagerTest - 任務0排入佇列
2018-01-17 10:07:28,451 [main] INFO ManagerTest - 任務1排入佇列
2018-01-17 10:07:29,451 [main] INFO ManagerTest - 任務2排入佇列
2018-01-17 10:07:32,451 [Consumer Expiration Thread] INFO ConsumerInfoManager - 任務已到期,topic:chao-0, userID:dhsajkdsajkdsjh1,subscribed:false
2018-01-17 10:07:33,485 [Consumer Expiration Thread] INFO ConsumerInfoManager - 任務已到期,topic:chao-1, userID:dhsajkdsajkdsjh1,subscribed:false
2018-01-17 10:07:34,452 [Consumer Expiration Thread] INFO ConsumerInfoManager - 任務已到期,topic:chao-2, userID:dhsajkdsajkdsjh1,subscribed:false

 轉寄請註明出處: http://www.cnblogs.com/jycboy/p/8301538.html