springboot+websocket實現並發搶紅包功能
概述
搶紅包功能作為幾大高並發場景中典型，應該如何實現？
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：
- 發紅包；主要填寫紅包信息，生成紅包記錄
- 紅包支付回調；用戶發紅包支付成功後，收到微信支付付款成功的回調，生成指定數量的紅包。
- 搶紅包；用戶並發搶紅包。
- 拆紅包；記錄用戶搶紅包記錄，轉賬搶到的紅包金額。
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。
設計開發
表結構設計
紅包記錄在 redpacket 表中，用戶領取紅包詳情記錄在 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 '紅包數量', `order_status` int(4) NOT NULL DEFAULT '0' COMMENT '訂單狀態：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 '是否領取0未領取、1已領取', `create_time` datetime NOT NULL COMMENT '創建時間', `update_time` datetime NOT NULL COMMENT '更新時間', `user_id` varchar(32) DEFAULT NULL COMMENT '領取用戶', `packet_no` varchar(32) NOT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COMMENT='紅包詳情表';
發紅包設計
用戶需要填寫紅包金額、紅包數量、備註信息等，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("-", "");
//拿到收銀臺下單結果，更新訂單為待支付狀態
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;
}
紅包支付成功回調設計
用戶支付成功後，系統接收到微信回調接口。
更新紅包支付狀態
二倍均值法生成指定數量紅包，並批量入庫。 紅包算法參考：Java實現4種微信搶紅包算法
紅包總數入redis，設置紅包過期時間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
//更新訂單支付狀態
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));
}
}
/**
* 紅包隨機算法
*
* @param amount 紅包金額
* @param num 紅包數量
* @return 隨機紅包集合
*/
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);
//出去最少紅包金額後剩餘金額
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內隨機獲得的整數
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;
}
頁面加載成功後初始化websocket,監聽後端新紅包生成成功，動態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("此瀏覽器隻支持MozWebSocket");
} else {
alert("此瀏覽器隻支持SockJS");
}
websocket.onopen = function(evnt) {
console.log("鏈接服務器成功!")
};
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("與服務器斷開瞭鏈接!")
}
});
搶紅包設計
搶紅包設計高並發，本地單機項目，通過原子Integer控制搶紅包接口並發限制為20，
private AtomicInteger receiveCount = new AtomicInteger(0);
@PostMapping("/receive")
public CommonJsonResponse receiveOne(@Validated @RequestBody CommonJsonRequest<ReqReceiveRedPacketVO> vo) {
Integer num = null;
try {
//控制並發不要超過20
if (receiveCount.get() > 20) {
return new CommonJsonResponse("9999", "太快瞭");
}
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();
}
}
}
對於沒有領取過該紅包的用戶，在紅包沒有過期且紅包還有剩餘的情況下，搶紅包成功，記錄成功標識入redis,設置標識過期時間為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 "該紅包已經領取過瞭";
}
final String receiveKey = REDPACKET_RECEIVE_PREFIX + redPacketNo + ":" + data.getUserId();
//優化成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 "太快瞭";
}
return "";
}
拆紅包設計
在用戶搶紅包成功標識未過期的狀態下，且紅包未過期紅包未領完時，從數據庫中領取一個紅包，領取成功將領取記錄寫入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("紅包飛走瞭", ExceptionType.SYS_ERR);
}
redisTemplate.delete(receiveKey);
if (!redisTemplate.hasKey(redisKey)) {
log.info("紅包過期瞭，packet:{}", packetNo);
throw new ServiceException("紅包飛走瞭", ExceptionType.SYS_ERR);
}
num = redisTemplate.opsForValue().increment(redisKey, -1);
if (num < 0L) {
log.info("紅包領完瞭，packet:{}", packetNo);
throw new ServiceException("紅包飛走瞭", ExceptionType.SYS_ERR);
}
final int i = detailMapper.receiveOne(packetId, packetNo, userId);
if (i != 1) {
log.info("紅包真的領完瞭，packet:{}", packetNo);
throw new ServiceException("紅包飛走瞭", 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("已經領取過瞭，packet:{}，user:{}", packetNo, userId);
throw new ServiceException("紅包飛走瞭", 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("紅包飛走瞭", ExceptionType.SYS_ERR);
}
}
其中 detailMapper.receiveOne(packetId, packetNo, userId); sql如下，將指定紅包記錄下未領取的紅包更新一條未當前用戶已經領取，若成功更新一條則表示領取成功，否則領取失敗。
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
獲取紅包領取記錄設計
直接充redis中獲取用戶領取記錄，沒有則直接獲取數據庫並同步至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並發測試搶紅包、查紅包接口
設置jmeter參數1秒中並發請求50個搶11個紅包，可以看到，前面的請求都是成功的，中間並發量上來後有部分達到並發上限被攔截，後面紅包搶完請求全部失敗。
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