springboot+websocket實現(xiàn)并發(fā)搶紅包功能

更新時間：2021年12月21日 11:39:19 作者：泰克農(nóng)民工

本文主要介紹了springboot+websocket實現(xiàn)并發(fā)搶紅包功能，主要包含了4種步驟，文中通過示例代碼介紹的非常詳細(xì)，具有一定的參考價值，感興趣的小伙伴們可以參考一下

概述

搶紅包功能作為幾大高并發(fā)場景中典型，應(yīng)該如何實現(xiàn)？

源碼地址：https://gitee.com/tech-famer/farmer-redpacket

分析

參考微信搶紅包功能，將搶紅包分成一下幾個步驟：

發(fā)紅包；主要填寫紅包信息，生成紅包記錄
紅包支付回調(diào)；用戶發(fā)紅包支付成功后，收到微信支付付款成功的回調(diào)，生成指定數(shù)量的紅包。
搶紅包；用戶并發(fā)搶紅包。
拆紅包；記錄用戶搶紅包記錄，轉(zhuǎn)賬搶到的紅包金額。

?效果展示

項目使用sessionId模擬用戶，示例打開倆個瀏覽器窗口模擬兩個用戶。

在這里插入圖片描述

設(shè)計開發(fā)

表結(jié)構(gòu)設(shè)計

紅包記錄在 redpacket 表中，用戶領(lǐng)取紅包詳情記錄在 redpacket_detail 表中。

CREATE DATABASE  `redpacket`;

use `redpacket`;

CREATE TABLE `redpacket`.`redpacket` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT COMMENT '主鍵ID',
  `packet_no` varchar(32) NOT NULL COMMENT '訂單號',
  `amount` decimal(5,2) NOT NULL COMMENT '紅包金額最高10000.00元',
  `num` int(11) NOT NULL COMMENT '紅包數(shù)量',
  `order_status` int(4) NOT NULL DEFAULT '0' COMMENT '訂單狀態(tài)：0初始、1待支付、2支付成功、3取消',
  `pay_seq` varchar(32) DEFAULT NULL COMMENT '支付流水號',
  `create_time` datetime NOT NULL COMMENT '創(chuàng)建時間',
  `user_id` varchar(32) NOT NULL COMMENT '用戶ID',
  `update_time` datetime NOT NULL COMMENT '更新時間',
  `pay_time` datetime DEFAULT NULL COMMENT '支付時間',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB  DEFAULT CHARSET=utf8 COMMENT='紅包訂單表';

CREATE TABLE `redpacket`.`redpacket_detail` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT COMMENT '主鍵ID',
  `packet_id` bigint(20) NOT NULL COMMENT '紅包ID',
  `amount` decimal(5,2) NOT NULL COMMENT '紅包金額',
  `received` int(1) NOT NULL DEFAULT '0' COMMENT '是否領(lǐng)取0未領(lǐng)取、1已領(lǐng)取',
  `create_time` datetime NOT NULL COMMENT '創(chuàng)建時間',
  `update_time` datetime NOT NULL COMMENT '更新時間',
  `user_id` varchar(32) DEFAULT NULL COMMENT '領(lǐng)取用戶',
  `packet_no` varchar(32) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB  DEFAULT CHARSET=utf8 COMMENT='紅包詳情表';

發(fā)紅包設(shè)計

用戶需要填寫紅包金額、紅包數(shù)量、備注信息等，生成紅包記錄，微信收銀臺下單，返回用戶支付。

public RedPacket generateRedPacket(ReqSendRedPacketsVO data,String userId) {
    final BigDecimal amount = data.getAmount();
    //紅包數(shù)量
    final Integer num = data.getNum();

    //初始化訂單
    final RedPacket redPacket = new RedPacket();
    redPacket.setPacketNo(UUID.randomUUID().toString().replace("-", ""));
    redPacket.setAmount(amount);
    redPacket.setNum(num);
    redPacket.setUserId(userId);
    Date now = new Date();
    redPacket.setCreateTime(now);
    redPacket.setUpdateTime(now);
    int i = redPacketMapper.insertSelective(redPacket);
    if (i != 1) {
        throw new ServiceException("生成紅包出錯", ExceptionType.SYS_ERR);
    }

    //模擬收銀臺下單
    String paySeq = UUID.randomUUID().toString().replace("-", "");

    //拿到收銀臺下單結(jié)果，更新訂單為待支付狀態(tài)
    redPacket.setOrderStatus(1);//待支付
    redPacket.setPaySeq(paySeq);
    i = redPacketMapper.updateByPrimaryKeySelective(redPacket);
    if (i != 1) {
        throw new ServiceException("生成紅包出錯", ExceptionType.SYS_ERR);
    }
    return redPacket;
}

在這里插入圖片描述

紅包支付成功回調(diào)設(shè)計

用戶支付成功后，系統(tǒng)接收到微信回調(diào)接口。

更新紅包支付狀態(tài)
二倍均值法生成指定數(shù)量紅包，并批量入庫。紅包算法參考：Java實現(xiàn)4種微信搶紅包算法
紅包總數(shù)入redis，設(shè)置紅包過期時間24小時
websocket通知在線用戶收到新的紅包

@Transactional(rollbackFor = Exception.class)
public void dealAfterOrderPayCallback(String userId,ReqOrderPayCallbackVO data) {
    RedPacketExample example = new RedPacketExample();
    final String packetNo = data.getPacketNo();
    final String paySeq = data.getPaySeq();
    final Integer payStatus = data.getPayStatus();
    example.createCriteria().andPacketNoEqualTo(packetNo)
            .andPaySeqEqualTo(paySeq)
            .andOrderStatusEqualTo(1);//待支付狀態(tài)
    //更新訂單支付狀態(tài)
    Date now = new Date();
    RedPacket updateRedPacket = new RedPacket();
    updateRedPacket.setOrderStatus(payStatus);
    updateRedPacket.setUpdateTime(now);
    updateRedPacket.setPayTime(now);
    int i = redPacketMapper.updateByExampleSelective(updateRedPacket, example);
    if (i != 1) {
        throw new ServiceException("訂單狀態(tài)更新失敗", ExceptionType.SYS_ERR);
    }

    if (payStatus == 2) {
        RedPacketExample query = new RedPacketExample();
        query.createCriteria().andPacketNoEqualTo(packetNo)
                .andPaySeqEqualTo(paySeq)
                .andOrderStatusEqualTo(2);
        final RedPacket redPacket = redPacketMapper.selectByExample(query).get(0);
        final List<BigDecimal> detailList = getRedPacketDetail(redPacket.getAmount(), redPacket.getNum());
        final int size = detailList.size();
        if (size <= 100) {
            i = detailMapper.batchInsert(detailList, redPacket);
            if (size != i) {
                throw new ServiceException("生成紅包失敗", ExceptionType.SYS_ERR);
            }
        } else {
            int times = size % 100 == 0 ? size / 100 : (size / 100 + 1);
            for (int j = 0; j < times; j++) {
                int fromIndex = 100 * j;
                int toIndex = 100 * (j + 1) - 1;
                if (toIndex > size - 1) {
                    toIndex = size - 1;
                }
                final List<BigDecimal> subList = detailList.subList(fromIndex, toIndex);
                i = detailMapper.batchInsert(subList, redPacket);
                if (subList.size() != i) {
                    throw new ServiceException("生成紅包失敗", ExceptionType.SYS_ERR);
                }
            }
        }

        final String redisKey = REDPACKET_NUM_PREFIX + redPacket.getPacketNo();

        String lua = "local i = redis.call('setnx',KEYS[1],ARGV[1])\r\n" +
                "if i == 1 then \r\n" +
                "   local j = redis.call('expire',KEYS[1],ARGV[2])\r\n" +
                "end \r\n" +
                "return i";
        //優(yōu)化成lua腳本
        final Long execute = redisTemplate.execute(new DefaultRedisScript<>(lua, Long.class), Arrays.asList(redisKey), size, 3600 * 24);
        if (execute != 1L) {
            throw new ServiceException("生成紅包失敗", ExceptionType.SYS_ERR);
        }
        //websocket通知在線用戶收到新的紅包
        Websocket.sendMessageToUser(userId, JSONObject.toJSONString(redPacket));
    }
}


/**
 * 紅包隨機(jī)算法
 *
 * @param amount 紅包金額
 * @param num    紅包數(shù)量
 * @return 隨機(jī)紅包集合
 */
private List<BigDecimal> getRedPacketDetail(BigDecimal amount, Integer num) {
    List<BigDecimal> redPacketsList = new ArrayList<>(num);
    //最小紅包金額
    final BigDecimal min = new BigDecimal("0.01");
    //最少需要紅包金額
    final BigDecimal bigNum = new BigDecimal(num);
    final BigDecimal atLastAmount = min.multiply(bigNum);
    //出去最少紅包金額后剩余金額
    BigDecimal remain = amount.subtract(atLastAmount);
    if (remain.compareTo(BigDecimal.ZERO) == 0) {
        for (int i = 0; i < num; i++) {
            redPacketsList.add(min);
        }
        return redPacketsList;
    }

    final Random random = new Random();
    final BigDecimal hundred = new BigDecimal("100");
    final BigDecimal two = new BigDecimal("2");
    BigDecimal redPacket;
    for (int i = 0; i < num; i++) {
        if (i == num - 1) {
            redPacket = remain;
        } else {
            //100內(nèi)隨機(jī)獲得的整數(shù)
            final int rand = random.nextInt(100);
            redPacket = new BigDecimal(rand).multiply(remain.multiply(two).divide(bigNum.subtract(new BigDecimal(i)), 2, RoundingMode.CEILING)).divide(hundred, 2, RoundingMode.FLOOR);
        }
        if (remain.compareTo(redPacket) > 0) {
            remain = remain.subtract(redPacket);
        } else {
            remain = BigDecimal.ZERO;
        }
        redPacketsList.add(min.add(redPacket));
    }

    return redPacketsList;
}

頁面加載成功后初始化websocket,監(jiān)聽后端新紅包生成成功，動態(tài)添加紅包到聊天窗口。

$(function (){
    var websocket;
    if('WebSocket' in window) {
        console.log("此瀏覽器支持websocket");
        websocket = new WebSocket("ws://127.0.0.1:8082/websocket/${session.id}");
    } else if('MozWebSocket' in window) {
        alert("此瀏覽器只支持MozWebSocket");
    } else {
        alert("此瀏覽器只支持SockJS");
    }
    websocket.onopen = function(evnt) {
        console.log("鏈接服務(wù)器成功!")
    };
    websocket.onmessage = function(evnt) {
        console.log(evnt.data);
        var json = eval('('+evnt.data+ ')');
        obj.addPacket(json.id,json.packetNo,json.userId)

    };
    websocket.onerror = function(evnt) {};
    websocket.onclose = function(evnt) {
        console.log("與服務(wù)器斷開了鏈接!")
    }
});

搶紅包設(shè)計

搶紅包設(shè)計高并發(fā)，本地單機(jī)項目，通過原子Integer控制搶紅包接口并發(fā)限制為20，

private AtomicInteger receiveCount = new AtomicInteger(0);

@PostMapping("/receive")
public CommonJsonResponse receiveOne(@Validated @RequestBody CommonJsonRequest<ReqReceiveRedPacketVO> vo) {
    Integer num = null;
    try {
        //控制并發(fā)不要超過20
        if (receiveCount.get() > 20) {
            return new CommonJsonResponse("9999", "太快了");
        }
        num = receiveCount.incrementAndGet();
        final String s = orderService.receiveOne(vo.getData());
        return StringUtils.isEmpty(s) ? CommonJsonResponse.ok() : new CommonJsonResponse("9999", s);
    } finally {
        if (num != null) {
            receiveCount.decrementAndGet();
        }
    }
}

對于沒有領(lǐng)取過該紅包的用戶，在紅包沒有過期且紅包還有剩余的情況下，搶紅包成功，記錄成功標(biāo)識入redis,設(shè)置標(biāo)識過期時間為5秒。

public String receiveOne(ReqReceiveRedPacketVO data) {
    final Long redPacketId = data.getPacketId();
    final String redPacketNo = data.getPacketNo();
    final String redisKey = REDPACKET_NUM_PREFIX + redPacketNo;
    if (!redisTemplate.hasKey(redisKey)) {
        return "紅包已經(jīng)過期";
    }
    final Integer num = (Integer) redisTemplate.opsForValue().get(redisKey);
    if (num <= 0) {
        return "紅包已搶完";
    }
    RedPacketDetailExample example = new RedPacketDetailExample();
    example.createCriteria().andPacketIdEqualTo(redPacketId)
            .andReceivedEqualTo(1)
            .andUserIdEqualTo(data.getUserId());
    final List<RedPacketDetail> details = detailMapper.selectByExample(example);
    if (!details.isEmpty()) {
        return "該紅包已經(jīng)領(lǐng)取過了";
    }
    final String receiveKey = REDPACKET_RECEIVE_PREFIX + redPacketNo + ":" + data.getUserId();

    //優(yōu)化成lua腳本
    String lua = "local i = redis.call('setnx',KEYS[1],ARGV[1])\r\n" +
            "if i == 1 then \r\n" +
            "   local j = redis.call('expire',KEYS[1],ARGV[2])\r\n" +
            "end \r\n" +
            "return i";
    //優(yōu)化成lua腳本
    final Long execute = redisTemplate.execute(new DefaultRedisScript<>(lua, Long.class), Arrays.asList(receiveKey), 1, 5);
    if (execute != 1L) {
        return "太快了";
    }
    return "";
}

拆紅包設(shè)計

在用戶搶紅包成功標(biāo)識未過期的狀態(tài)下，且紅包未過期紅包未領(lǐng)完時，從數(shù)據(jù)庫中領(lǐng)取一個紅包，領(lǐng)取成功將領(lǐng)取記錄寫入redis以供查詢過期時間為48小時。

@Transactional(rollbackFor = Exception.class)
public String openRedPacket(ReqReceiveRedPacketVO data) {
    final Long packetId = data.getPacketId();
    final String packetNo = data.getPacketNo();
    final String userId = data.getUserId();
    final String redisKey = REDPACKET_NUM_PREFIX + packetNo;
    Long num = null;
    try {
        final String receiveKey = REDPACKET_RECEIVE_PREFIX + packetNo + ":" + userId;
        if (!redisTemplate.hasKey(receiveKey)) {
            log.info("未獲取到紅包資格，packet:{},user:{}", packetNo, userId);
            throw new ServiceException("紅包飛走了", ExceptionType.SYS_ERR);
        }
        redisTemplate.delete(receiveKey);
        if (!redisTemplate.hasKey(redisKey)) {
            log.info("紅包過期了，packet:{}", packetNo);
            throw new ServiceException("紅包飛走了", ExceptionType.SYS_ERR);
        }
        num = redisTemplate.opsForValue().increment(redisKey, -1);
        if (num < 0L) {
            log.info("紅包領(lǐng)完了，packet:{}", packetNo);
            throw new ServiceException("紅包飛走了", ExceptionType.SYS_ERR);
        }
        final int i = detailMapper.receiveOne(packetId, packetNo, userId);
        if (i != 1) {
            log.info("紅包真的領(lǐng)完了，packet:{}", packetNo);
            throw new ServiceException("紅包飛走了", ExceptionType.SYS_ERR);
        }
        RedPacketDetailExample example = new RedPacketDetailExample();
        example.createCriteria().andPacketIdEqualTo(packetId)
                .andReceivedEqualTo(1)
                .andUserIdEqualTo(userId);
        final List<RedPacketDetail> details = detailMapper.selectByExample(example);
        if (details.size() != 1) {
            log.info("已經(jīng)領(lǐng)取過了，packet:{}，user:{}", packetNo, userId);
            throw new ServiceException("紅包飛走了", ExceptionType.SYS_ERR);
        }
        //處理加款
        log.info("搶到紅包金額{}，packet:{}，user:{}", details.get(0).getAmount(), packetNo, userId);
        final String listKey = REDPACKET_LIST_PREFIX + packetNo;
        redisTemplate.opsForList().leftPush(listKey,details.get(0));
        redisTemplate.expire(redisKey, 48, TimeUnit.HOURS);
        return "" + details.get(0).getAmount();
    } catch (Exception e) {
        if (num != null) {
            redisTemplate.opsForValue().increment(redisKey, 1L);
        }
        log.warn("打開紅包異常", e);
        throw new ServiceException("紅包飛走了", ExceptionType.SYS_ERR);
    }
}

其中 detailMapper.receiveOne(packetId, packetNo, userId); sql如下，將指定紅包記錄下未領(lǐng)取的紅包更新一條未當(dāng)前用戶已經(jīng)領(lǐng)取，若成功更新一條則表示領(lǐng)取成功，否則領(lǐng)取失敗。

update redpacket_detail d
set received = 1,update_time = now(),user_id = #{userId,jdbcType=VARCHAR}
where received = 0
and packet_id = #{packetId,jdbcType=BIGINT}
and packet_no = #{packetNo,jdbcType=VARCHAR}
and user_id is null
limit 1

獲取紅包領(lǐng)取記錄設(shè)計

直接充redis中獲取用戶領(lǐng)取記錄，沒有則直接獲取數(shù)據(jù)庫并同步至redis。

public RespReceiveListVO receiveList(ReqReceiveListVO data) {
    //紅包記錄redisKey
    final String packetNo = data.getPacketNo();
    final String redisKey = REDPACKET_LIST_PREFIX + packetNo;
    if (!redisTemplate.hasKey(redisKey)) {
        RedPacketDetailExample example = new RedPacketDetailExample();
        example.createCriteria().andPacketNoEqualTo(packetNo)
                .andReceivedEqualTo(1);
        final List<RedPacketDetail> list = detailMapper.selectByExample(example);
        redisTemplate.opsForList().leftPushAll(redisKey, list);
        redisTemplate.expire(redisKey, 24, TimeUnit.HOURS);
    }
    List retList = redisTemplate.opsForList().range(redisKey, 0, -1);
    final Object collect = retList.stream().map(item -> {
        final JSONObject packetDetail = (JSONObject) item;
        return ReceiveRecordVO.builder()
                .amount(packetDetail.getBigDecimal("amount"))
                .receiveTime(packetDetail.getDate("updateTime"))
                .userId(packetDetail.getString("userId"))
                .packetId(packetDetail.getLong("redpacketId"))
                .packetNo(packetDetail.getString("redpacketNo"))
                .build();
    }).collect(Collectors.toList());
    return RespReceiveListVO.builder().list((List) collect).build();
}

jmeter并發(fā)測試搶紅包、查紅包接口

設(shè)置jmeter參數(shù)1秒中并發(fā)請求50個搶11個紅包，可以看到，前面的請求都是成功的，中間并發(fā)量上來后有部分達(dá)到并發(fā)上限被攔截，后面紅包搶完請求全部失敗。

在這里插入圖片描述

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