Redis 抽獎大轉盤的實戰示例
1. 項目介紹
這是一個基於Spring boot + Mybatis Plus + Redis 的簡單案例。
主要是將活動內容、獎品信息、記錄信息等緩存到Redis中，然後所有的抽獎過程全部從Redis中做數據的操作。
大致內容很簡單，具體操作下面慢慢分析。
2. 項目演示
話不多說，首先上圖看看項目效果，如果覺得還行的話咱們就來看看他具體是怎麼實現的。
3. 表結構
該項目包含以下四張表，分別是活動表、獎項表、獎品表以及中獎記錄表。具體的SQL會在文末給出。
4. 項目搭建
咱們首先先搭建一個標準的Spring boot 項目，直接IDEA創建，然後選擇一些相關的依賴即可。
4.1 依賴
該項目主要用到瞭：Redis，thymeleaf，mybatis-plus等依賴。
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-boot-starter</artifactId>
<version>3.4.3</version>
</dependency>
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-generator</artifactId>
<version>3.4.1</version>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.72</version>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid-spring-boot-starter</artifactId>
<version>1.1.22</version>
</dependency>
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-lang3</artifactId>
<version>3.9</version>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>1.18.12</version>
</dependency>
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-pool2</artifactId>
<version>2.8.0</version>
</dependency>
<dependency>
<groupId>org.mapstruct</groupId>
<artifactId>mapstruct</artifactId>
<version>1.4.2.Final</version>
</dependency>
<dependency>
<groupId>org.mapstruct</groupId>
<artifactId>mapstruct-jdk8</artifactId>
<version>1.4.2.Final</version>
</dependency>
<dependency>
<groupId>org.mapstruct</groupId>
<artifactId>mapstruct-processor</artifactId>
<version>1.4.2.Final</version>
</dependency>
<dependency>
<groupId>joda-time</groupId>
<artifactId>joda-time</artifactId>
<version>2.10.6</version>
</dependency>
</dependencies>
4.2 YML配置
依賴引入之後，我們需要進行相應的配置：數據庫連接信息、Redis、mybatis-plus、線程池等。
server:
port: 8080
servlet:
context-path: /
spring:
datasource:
druid:
url: jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&characterEncoding=utf-8&useSSL=false
username: root
password: 123456
driver-class-name: com.mysql.cj.jdbc.Driver
initial-size: 30
max-active: 100
min-idle: 10
max-wait: 60000
time-between-eviction-runs-millis: 60000
min-evictable-idle-time-millis: 300000
validation-query: SELECT 1 FROM DUAL
test-while-idle: true
test-on-borrow: false
test-on-return: false
filters: stat,wall
redis:
port: 6379
host: 127.0.0.1
lettuce:
pool:
max-active: -1
max-idle: 2000
max-wait: -1
min-idle: 1
time-between-eviction-runs: 5000
mvc:
view:
prefix: classpath:/templates/
suffix: .html
# mybatis-plus
mybatis-plus:
configuration:
map-underscore-to-camel-case: true
auto-mapping-behavior: full
mapper-locations: classpath*:mapper/**/*Mapper.xml
# 線程池
async:
executor:
thread:
core-pool-size: 6
max-pool-size: 12
queue-capacity: 100000
name-prefix: lottery-service-
4.3 代碼生成
這邊我們可以直接使用mybatis-plus的代碼生成器幫助我們生成一些基礎的業務代碼，避免這些重復的體力活。
這邊貼出相關代碼，直接修改數據庫連接信息、相關包名模塊名即可。
public class MybatisPlusGeneratorConfig {
public static void main(String[] args) {
// 代碼生成器
AutoGenerator mpg = new AutoGenerator();
// 全局配置
GlobalConfig gc = new GlobalConfig();
String projectPath = System.getProperty("user.dir");
gc.setOutputDir(projectPath + "/src/main/java");
gc.setAuthor("chen");
gc.setOpen(false);
//實體屬性 Swagger2 註解
gc.setSwagger2(false);
mpg.setGlobalConfig(gc);
// 數據源配置
DataSourceConfig dsc = new DataSourceConfig();
dsc.setUrl("jdbc:mysql://127.0.0.1:3306/test?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8&zeroDateTimeBehavior=convertToNull&useSSL=false&allowPublicKeyRetrieval=true");
dsc.setDriverName("com.mysql.cj.jdbc.Driver");
dsc.setUsername("root");
dsc.setPassword("123456");
mpg.setDataSource(dsc);
// 包配置
PackageConfig pc = new PackageConfig();
// pc.setModuleName(scanner("模塊名"));
pc.setParent("com.example.lottery");
pc.setEntity("dal.model");
pc.setMapper("dal.mapper");
pc.setService("service");
pc.setServiceImpl("service.impl");
mpg.setPackageInfo(pc);
// 配置模板
TemplateConfig templateConfig = new TemplateConfig();
templateConfig.setXml(null);
mpg.setTemplate(templateConfig);
// 策略配置
StrategyConfig strategy = new StrategyConfig();
strategy.setNaming(NamingStrategy.underline_to_camel);
strategy.setColumnNaming(NamingStrategy.underline_to_camel);
strategy.setSuperEntityClass("com.baomidou.mybatisplus.extension.activerecord.Model");
strategy.setEntityLombokModel(true);
strategy.setRestControllerStyle(true);
strategy.setEntityLombokModel(true);
// 公共父類
// strategy.setSuperControllerClass("com.baomidou.ant.common.BaseController");
// 寫於父類中的公共字段
// strategy.setSuperEntityColumns("id");
strategy.setInclude(scanner("lottery,lottery_item,lottery_prize,lottery_record").split(","));
strategy.setControllerMappingHyphenStyle(true);
strategy.setTablePrefix(pc.getModuleName() + "_");
mpg.setStrategy(strategy);
mpg.setTemplateEngine(new FreemarkerTemplateEngine());
mpg.execute();
}
public static String scanner(String tip) {
Scanner scanner = new Scanner(System.in);
StringBuilder help = new StringBuilder();
help.append("請輸入" + tip + "：");
System.out.println(help.toString());
if (scanner.hasNext()) {
String ipt = scanner.next();
if (StringUtils.isNotEmpty(ipt)) {
return ipt;
}
}
throw new MybatisPlusException("請輸入正確的" + tip + "！");
}
}
4.4 Redis 配置
我們如果在代碼中使用 RedisTemplate 的話，需要添加相關配置，將其註入到Spring容器中。
@Configuration
public class RedisTemplateConfig {
@Bean
public RedisTemplate redisTemplate(RedisConnectionFactory redisConnectionFactory) {
RedisTemplate<Object, Object> redisTemplate = new RedisTemplate<>();
redisTemplate.setConnectionFactory(redisConnectionFactory);
// 使用Jackson2JsonRedisSerialize 替換默認序列化
Jackson2JsonRedisSerializer jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer(Object.class);
ObjectMapper objectMapper = new ObjectMapper();
objectMapper.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
objectMapper.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL);
SimpleModule simpleModule = new SimpleModule();
simpleModule.addSerializer(DateTime.class, new JodaDateTimeJsonSerializer());
simpleModule.addDeserializer(DateTime.class, new JodaDateTimeJsonDeserializer());
objectMapper.registerModule(simpleModule);
jackson2JsonRedisSerializer.setObjectMapper(objectMapper);
// 設置value的序列化規則和 key的序列化規則
redisTemplate.setValueSerializer(jackson2JsonRedisSerializer);
redisTemplate.setKeySerializer(new StringRedisSerializer());
redisTemplate.setHashKeySerializer(new StringRedisSerializer());
redisTemplate.setHashValueSerializer(jackson2JsonRedisSerializer);
redisTemplate.afterPropertiesSet();
return redisTemplate;
}
}
class JodaDateTimeJsonSerializer extends JsonSerializer<DateTime> {
@Override
public void serialize(DateTime dateTime, JsonGenerator jsonGenerator, SerializerProvider serializerProvider) throws IOException {
jsonGenerator.writeString(dateTime.toString("yyyy-MM-dd HH:mm:ss"));
}
}
class JodaDateTimeJsonDeserializer extends JsonDeserializer<DateTime> {
@Override
public DateTime deserialize(JsonParser jsonParser, DeserializationContext deserializationContext) throws IOException, JsonProcessingException {
String dateString = jsonParser.readValueAs(String.class);
DateTimeFormatter dateTimeFormatter = DateTimeFormat.forPattern("yyyy-MM-dd HH:mm:ss");
return dateTimeFormatter.parseDateTime(dateString);
}
}
4.5 常量管理
由於代碼中會用到一些共有的常量，我們應該將其抽離出來。
public class LotteryConstants {
/**
* 表示正在抽獎的用戶標記
*/
public final static String DRAWING = "DRAWING";
/**
* 活動標記 LOTTERY:lotteryID
*/
public final static String LOTTERY = "LOTTERY";
/**
* 獎品數據 LOTTERY_PRIZE:lotteryID:PrizeId
*/
public final static String LOTTERY_PRIZE = "LOTTERY_PRIZE";
/**
* 默認獎品數據 DEFAULT_LOTTERY_PRIZE:lotteryID
*/
public final static String DEFAULT_LOTTERY_PRIZE = "DEFAULT_LOTTERY_PRIZE";
public enum PrizeTypeEnum {
THANK(-1), NORMAL(1), UNIQUE(2);
private int value;
private PrizeTypeEnum(int value) {
this.value = value;
}
public int getValue() {
return this.value;
}
}
/**
* 獎項緩存：LOTTERY_ITEM:LOTTERY_ID
*/
public final static String LOTTERY_ITEM = "LOTTERY_ITEM";
/**
* 默認獎項： DEFAULT_LOTTERY_ITEM:LOTTERY_ID
*/
public final static String DEFAULT_LOTTERY_ITEM = "DEFAULT_LOTTERY_ITEM";
}
public enum ReturnCodeEnum {
SUCCESS("0000", "成功"),
LOTTER_NOT_EXIST("9001", "指定抽獎活動不存在"),
LOTTER_FINISH("9002", "活動已結束"),
LOTTER_REPO_NOT_ENOUGHT("9003", "當前獎品庫存不足"),
LOTTER_ITEM_NOT_INITIAL("9004", "獎項數據未初始化"),
LOTTER_DRAWING("9005", "上一次抽獎還未結束"),
REQUEST_PARAM_NOT_VALID("9998", "請求參數不正確"),
SYSTEM_ERROR("9999", "系統繁忙,請稍後重試");
private String code;
private String msg;
private ReturnCodeEnum(String code, String msg) {
this.code = code;
this.msg = msg;
}
public String getCode() {
return code;
}
public String getMsg() {
return msg;
}
public String getCodeString() {
return getCode() + "";
}
}
對Redis中的key進行統一的管理。
public class RedisKeyManager {
/**
* 正在抽獎的key
*
* @param accountIp
* @return
*/
public static String getDrawingRedisKey(String accountIp) {
return new StringBuilder(LotteryConstants.DRAWING).append(":").append(accountIp).toString();
}
/**
* 獲取抽獎活動的key
*
* @param id
* @return
*/
public static String getLotteryRedisKey(Integer id) {
return new StringBuilder(LotteryConstants.LOTTERY).append(":").append(id).toString();
}
/**
* 獲取指定活動下的所有獎品數據
*
* @param lotteryId
* @return
*/
public static String getLotteryPrizeRedisKey(Integer lotteryId) {
return new StringBuilder(LotteryConstants.LOTTERY_PRIZE).append(":").append(lotteryId).toString();
}
public static String getLotteryPrizeRedisKey(Integer lotteryId, Integer prizeId) {
return new StringBuilder(LotteryConstants.LOTTERY_PRIZE).append(":").append(lotteryId).append(":").append(prizeId).toString();
}
public static String getDefaultLotteryPrizeRedisKey(Integer lotteryId) {
return new StringBuilder(LotteryConstants.DEFAULT_LOTTERY_PRIZE).append(":").append(lotteryId).toString();
}
public static String getLotteryItemRedisKey(Integer lotteryId) {
return new StringBuilder(LotteryConstants.LOTTERY_ITEM).append(":").append(lotteryId).toString();
}
public static String getDefaultLotteryItemRedisKey(Integer lotteryId) {
return new StringBuilder(LotteryConstants.DEFAULT_LOTTERY_ITEM).append(":").append(lotteryId).toString();
}
}
4.6 業務代碼
4.6.1 抽獎接口
我們首先編寫抽獎接口，根據前臺傳的參數查詢到具體的活動，然後進行相應的操作。（當然，前端直接是寫死的/lottery/1）
@GetMapping("/{id}")
public ResultResp<LotteryItemVo> doDraw(@PathVariable("id") Integer id, HttpServletRequest request) {
String accountIp = CusAccessObjectUtil.getIpAddress(request);
log.info("begin LotteryController.doDraw,access user {}, lotteryId,{}:", accountIp, id);
ResultResp<LotteryItemVo> resultResp = new ResultResp<>();
try {
//判斷當前用戶上一次抽獎是否結束
checkDrawParams(id, accountIp);
//抽獎
DoDrawDto dto = new DoDrawDto();
dto.setAccountIp(accountIp);
dto.setLotteryId(id);
lotteryService.doDraw(dto);
//返回結果設置
resultResp.setCode(ReturnCodeEnum.SUCCESS.getCode());
resultResp.setMsg(ReturnCodeEnum.SUCCESS.getMsg());
//對象轉換
resultResp.setResult(lotteryConverter.dto2LotteryItemVo(dto));
} catch (Exception e) {
return ExceptionUtil.handlerException4biz(resultResp, e);
} finally {
//清除占位標記
redisTemplate.delete(RedisKeyManager.getDrawingRedisKey(accountIp));
}
return resultResp;
}
private void checkDrawParams(Integer id, String accountIp) {
if (null == id) {
throw new RewardException(ReturnCodeEnum.REQUEST_PARAM_NOT_VALID.getCode(), ReturnCodeEnum.REQUEST_PARAM_NOT_VALID.getMsg());
}
//采用setNx命令，判斷當前用戶上一次抽獎是否結束
Boolean result = redisTemplate.opsForValue().setIfAbsent(RedisKeyManager.getDrawingRedisKey(accountIp), "1", 60, TimeUnit.SECONDS);
//如果為false，說明上一次抽獎還未結束
if (!result) {
throw new RewardException(ReturnCodeEnum.LOTTER_DRAWING.getCode(), ReturnCodeEnum.LOTTER_DRAWING.getMsg());
}
}
為瞭避免用戶重復點擊抽獎，所以我們通過Redis來避免這種問題，用戶每次抽獎的時候，通過setNx給用戶排隊並設置過期時間；如果用戶點擊多次抽獎，Redis設置值的時候發現該用戶上次抽獎還未結束則拋出異常。
最後用戶抽獎成功的話，記得清除該標記，從而用戶能夠繼續抽獎。
4.6.2 初始化數據
從抽獎入口進來，校驗成功以後則開始業務操作。
@Override
public void doDraw(DoDrawDto drawDto) throws Exception {
RewardContext context = new RewardContext();
LotteryItem lotteryItem = null;
try {
//JUC工具 需要等待線程結束之後才能運行
CountDownLatch countDownLatch = new CountDownLatch(1);
//判斷活動有效性
Lottery lottery = checkLottery(drawDto);
//發佈事件，用來加載指定活動的獎品信息
applicationContext.publishEvent(new InitPrizeToRedisEvent(this, lottery.getId(), countDownLatch));
//開始抽獎
lotteryItem = doPlay(lottery);
//記錄獎品並扣減庫存
countDownLatch.await(); //等待獎品初始化完成
String key = RedisKeyManager.getLotteryPrizeRedisKey(lottery.getId(), lotteryItem.getPrizeId());
int prizeType = Integer.parseInt(redisTemplate.opsForHash().get(key, "prizeType").toString());
context.setLottery(lottery);
context.setLotteryItem(lotteryItem);
context.setAccountIp(drawDto.getAccountIp());
context.setKey(key);
//調整庫存及記錄中獎信息
AbstractRewardProcessor.rewardProcessorMap.get(prizeType).doReward(context);
} catch (UnRewardException u) { //表示因為某些問題未中獎，返回一個默認獎項
context.setKey(RedisKeyManager.getDefaultLotteryPrizeRedisKey(lotteryItem.getLotteryId()));
lotteryItem = (LotteryItem) redisTemplate.opsForValue().get(RedisKeyManager.getDefaultLotteryItemRedisKey(lotteryItem.getLotteryId()));
context.setLotteryItem(lotteryItem);
AbstractRewardProcessor.rewardProcessorMap.get(LotteryConstants.PrizeTypeEnum.THANK.getValue()).doReward(context);
}
//拼接返回數據
drawDto.setLevel(lotteryItem.getLevel());
drawDto.setPrizeName(context.getPrizeName());
drawDto.setPrizeId(context.getPrizeId());
}
首先我們通過CountDownLatch來保證商品初始化的順序，關於CountDownLatch可以查看 JUC工具 該文章。
然後我們需要檢驗一下活動的有效性，確保活動未結束。
檢驗活動通過後則通過ApplicationEvent 事件實現獎品數據的加載，將其存入Redis中。或者通過ApplicationRunner在程序啟動時獲取相關數據。我們這使用的是事件機制。ApplicationRunner 的相關代碼在下文我也順便貼出。
事件機制
public class InitPrizeToRedisEvent extends ApplicationEvent {
private Integer lotteryId;
private CountDownLatch countDownLatch;
public InitPrizeToRedisEvent(Object source, Integer lotteryId, CountDownLatch countDownLatch) {
super(source);
this.lotteryId = lotteryId;
this.countDownLatch = countDownLatch;
}
public Integer getLotteryId() {
return lotteryId;
}
public void setLotteryId(Integer lotteryId) {
this.lotteryId = lotteryId;
}
public CountDownLatch getCountDownLatch() {
return countDownLatch;
}
public void setCountDownLatch(CountDownLatch countDownLatch) {
this.countDownLatch = countDownLatch;
}
}
有瞭事件機制，我們還需要一個監聽事件，用來初始化相關數據信息。具體業務邏輯大傢可以參考下代碼，有相關的註釋信息，主要就是將數據庫中的數據添加進redis中，需要註意的是，我們為瞭保證原子性，是通過HASH來存儲數據的，這樣之後庫存扣減的時候就可以通過opsForHash來保證其原子性。
當初始化獎品信息之後，則通過countDown()方法表名執行完成，業務代碼中線程阻塞的地方可以繼續執行瞭。
@Slf4j
@Component
public class InitPrizeToRedisListener implements ApplicationListener<InitPrizeToRedisEvent> {
@Autowired
RedisTemplate redisTemplate;
@Autowired
LotteryPrizeMapper lotteryPrizeMapper;
@Autowired
LotteryItemMapper lotteryItemMapper;
@Override
public void onApplicationEvent(InitPrizeToRedisEvent initPrizeToRedisEvent) {
log.info("begin InitPrizeToRedisListener," + initPrizeToRedisEvent);
Boolean result = redisTemplate.opsForValue().setIfAbsent(RedisKeyManager.getLotteryPrizeRedisKey(initPrizeToRedisEvent.getLotteryId()), "1");
//已經初始化到緩存中瞭，不需要再次緩存
if (!result) {
log.info("already initial");
initPrizeToRedisEvent.getCountDownLatch().countDown();
return;
}
QueryWrapper<LotteryItem> lotteryItemQueryWrapper = new QueryWrapper<>();
lotteryItemQueryWrapper.eq("lottery_id", initPrizeToRedisEvent.getLotteryId());
List<LotteryItem> lotteryItems = lotteryItemMapper.selectList(lotteryItemQueryWrapper);
//如果指定的獎品沒有瞭，會生成一個默認的獎項
LotteryItem defaultLotteryItem = lotteryItems.parallelStream().filter(o -> o.getDefaultItem().intValue() == 1).findFirst().orElse(null);
Map<String, Object> lotteryItemMap = new HashMap<>(16);
lotteryItemMap.put(RedisKeyManager.getLotteryItemRedisKey(initPrizeToRedisEvent.getLotteryId()), lotteryItems);
lotteryItemMap.put(RedisKeyManager.getDefaultLotteryItemRedisKey(initPrizeToRedisEvent.getLotteryId()), defaultLotteryItem);
redisTemplate.opsForValue().multiSet(lotteryItemMap);
QueryWrapper queryWrapper = new QueryWrapper();
queryWrapper.eq("lottery_id", initPrizeToRedisEvent.getLotteryId());
List<LotteryPrize> lotteryPrizes = lotteryPrizeMapper.selectList(queryWrapper);
//保存一個默認獎項
AtomicReference<LotteryPrize> defaultPrize = new AtomicReference<>();
lotteryPrizes.stream().forEach(lotteryPrize -> {
if (lotteryPrize.getId().equals(defaultLotteryItem.getPrizeId())) {
defaultPrize.set(lotteryPrize);
}
String key = RedisKeyManager.getLotteryPrizeRedisKey(initPrizeToRedisEvent.getLotteryId(), lotteryPrize.getId());
setLotteryPrizeToRedis(key, lotteryPrize);
});
String key = RedisKeyManager.getDefaultLotteryPrizeRedisKey(initPrizeToRedisEvent.getLotteryId());
setLotteryPrizeToRedis(key, defaultPrize.get());
initPrizeToRedisEvent.getCountDownLatch().countDown(); //表示初始化完成
log.info("finish InitPrizeToRedisListener," + initPrizeToRedisEvent);
}
private void setLotteryPrizeToRedis(String key, LotteryPrize lotteryPrize) {
redisTemplate.setHashValueSerializer(new Jackson2JsonRedisSerializer<>(Object.class));
redisTemplate.opsForHash().put(key, "id", lotteryPrize.getId());
redisTemplate.opsForHash().put(key, "lotteryId", lotteryPrize.getLotteryId());
redisTemplate.opsForHash().put(key, "prizeName", lotteryPrize.getPrizeName());
redisTemplate.opsForHash().put(key, "prizeType", lotteryPrize.getPrizeType());
redisTemplate.opsForHash().put(key, "totalStock", lotteryPrize.getTotalStock());
redisTemplate.opsForHash().put(key, "validStock", lotteryPrize.getValidStock());
}
}
上面部分是通過事件的方法來初始化數據，下面我們說下ApplicationRunner的方式：
這種方式很簡單，在項目啟動的時候將數據加載進去即可。
我們隻需要實現ApplicationRunner接口即可，然後在run方法中從數據庫讀取數據加載到Redis中。
@Slf4j
@Component
public class LoadDataApplicationRunner implements ApplicationRunner {
@Autowired
RedisTemplate redisTemplate;
@Autowired
LotteryMapper lotteryMapper;
@Override
public void run(ApplicationArguments args) throws Exception {
log.info("=========begin load lottery data to Redis===========");
//加載當前抽獎活動信息
Lottery lottery = lotteryMapper.selectById(1);
log.info("=========finish load lottery data to Redis===========");
}
}
4.6.3 抽獎
我們在使用事件進行數據初始化的時候，可以同時進行抽獎操作，但是註意的是這個時候需要使用countDownLatch.await();來阻塞當前線程，等待數據初始化完成。
在抽獎的過程中，我們首先嘗試從Redis中獲取相關數據，如果Redis中沒有則從數據庫中加載數據，如果數據庫中也沒查詢到相關數據，則表明相關的數據沒有配置完成。
獲取數據之後，我們就該開始抽獎瞭。抽獎的核心在於隨機性以及概率性，咱們總不能隨便抽抽都能抽到一等獎吧？所以我們需要在表中設置每個獎項的概率性。如下所示：
在我們抽獎的時候需要根據概率劃分處相關區間。我們可以通過Debug的方式來查看一下具體怎麼劃分的：
獎項的概率越大，區間越大；大傢看到的順序是不同的，由於我們在上面通過Collections.shuffle(lotteryItems);將集合打亂瞭，所以這裡看到的不是順序展示的。
在生成對應區間後，我們通過生成隨機數，看隨機數落在那個區間中，然後將對應的獎項返回。這就實現瞭我們的抽獎過程。
private LotteryItem doPlay(Lottery lottery) {
LotteryItem lotteryItem = null;
QueryWrapper<LotteryItem> queryWrapper = new QueryWrapper<>();
queryWrapper.eq("lottery_id", lottery.getId());
Object lotteryItemsObj = redisTemplate.opsForValue().get(RedisKeyManager.getLotteryItemRedisKey(lottery.getId()));
List<LotteryItem> lotteryItems;
//說明還未加載到緩存中，同步從數據庫加載，並且異步將數據緩存
if (lotteryItemsObj == null) {
lotteryItems = lotteryItemMapper.selectList(queryWrapper);
} else {
lotteryItems = (List<LotteryItem>) lotteryItemsObj;
}
//獎項數據未配置
if (lotteryItems.isEmpty()) {
throw new BizException(ReturnCodeEnum.LOTTER_ITEM_NOT_INITIAL.getCode(), ReturnCodeEnum.LOTTER_ITEM_NOT_INITIAL.getMsg());
}
int lastScope = 0;
Collections.shuffle(lotteryItems);
Map<Integer, int[]> awardItemScope = new HashMap<>();
//item.getPercent=0.05 = 5%
for (LotteryItem item : lotteryItems) {
int currentScope = lastScope + new BigDecimal(item.getPercent().floatValue()).multiply(new BigDecimal(mulriple)).intValue();
awardItemScope.put(item.getId(), new int[]{lastScope + 1, currentScope});
lastScope = currentScope;
}
int luckyNumber = new Random().nextInt(mulriple);
int luckyPrizeId = 0;
if (!awardItemScope.isEmpty()) {
Set<Map.Entry<Integer, int[]>> set = awardItemScope.entrySet();
for (Map.Entry<Integer, int[]> entry : set) {
if (luckyNumber >= entry.getValue()[0] && luckyNumber <= entry.getValue()[1]) {
luckyPrizeId = entry.getKey();
break;
}
}
}
for (LotteryItem item : lotteryItems) {
if (item.getId().intValue() == luckyPrizeId) {
lotteryItem = item;
break;
}
}
return lotteryItem;
}
4.6.4 調整庫存及記錄
在調整庫存的時候，我們需要考慮到每個獎品類型的不同，根據不同類型的獎品采取不同的措施。比如如果是一些價值高昂的獎品，我們需要通過分佈式鎖來確保安全性；或者比如有些商品我們需要發送相應的短信；所以我們需要采取一種具有擴展性的實現機制。
具體的實現機制可以看下方的類圖，我首先定義一個獎品方法的接口（RewardProcessor），然後定義一個抽象類（AbstractRewardProcessor），抽象類中定義瞭模板方法，然後我們就可以根據不同的類型創建不同的處理器即可，這大大加強瞭我們的擴展性。
比如我們這邊就創建瞭庫存充足處理器及庫存不足處理器。
接口：
public interface RewardProcessor<T> {
void doReward(RewardContext context);
}
抽象類：
@Slf4j
public abstract class AbstractRewardProcessor implements RewardProcessor<RewardContext>, ApplicationContextAware {
public static Map<Integer, RewardProcessor> rewardProcessorMap = new ConcurrentHashMap<Integer, RewardProcessor>();
@Autowired
protected RedisTemplate redisTemplate;
private void beforeProcessor(RewardContext context) {
}
@Override
public void doReward(RewardContext context) {
beforeProcessor(context);
processor(context);
afterProcessor(context);
}
protected abstract void afterProcessor(RewardContext context);
/**
* 發放對應的獎品
*
* @param context
*/
protected abstract void processor(RewardContext context);
/**
* 返回當前獎品類型
*
* @return
*/
protected abstract int getAwardType();
@Override
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
rewardProcessorMap.put(LotteryConstants.PrizeTypeEnum.THANK.getValue(), (RewardProcessor) applicationContext.getBean(NoneStockRewardProcessor.class));
rewardProcessorMap.put(LotteryConstants.PrizeTypeEnum.NORMAL.getValue(), (RewardProcessor) applicationContext.getBean(HasStockRewardProcessor.class));
}
}
我們可以從抽象類中的doReward方法處開始查看，比如我們這邊先查看庫存充足處理器中的代碼：
庫存處理器執行的時候首相將Redis中對應的獎項庫存減1，這時候是不需要加鎖的，因為這個操作是原子性的。
當扣減後，我們根據返回的值判斷商品庫存是否充足，這個時候庫存不足則提示未中獎或者返回一個默認商品。
最後我們還需要記得更新下數據庫中的相關數據。
@Override
protected void processor(RewardContext context) {
//扣減庫存（redis的更新）
Long result = redisTemplate.opsForHash().increment(context.getKey(), "validStock", -1);
//當前獎品庫存不足，提示未中獎，或者返回一個兜底的獎品
if (result.intValue() < 0) {
throw new UnRewardException(ReturnCodeEnum.LOTTER_REPO_NOT_ENOUGHT.getCode(), ReturnCodeEnum.LOTTER_REPO_NOT_ENOUGHT.getMsg());
}
List<Object> propertys = Arrays.asList("id", "prizeName");
List<Object> prizes = redisTemplate.opsForHash().multiGet(context.getKey(), propertys);
context.setPrizeId(Integer.parseInt(prizes.get(0).toString()));
context.setPrizeName(prizes.get(1).toString());
//更新庫存（數據庫的更新）
lotteryPrizeMapper.updateValidStock(context.getPrizeId());
}
方法執行完成之後，我們需要執行afterProcessor方法：
這個地方我們是通過異步任務異步存入抽獎記錄信息。
@Override
protected void afterProcessor(RewardContext context) {
asyncLotteryRecordTask.saveLotteryRecord(context.getAccountIp(), context.getLotteryItem(), context.getPrizeName());
}
在這邊我們可以發現是通過Async註解，指定一個線程池，開啟一個異步執行的方法。
@Slf4j
@Component
public class AsyncLotteryRecordTask {
@Autowired
LotteryRecordMapper lotteryRecordMapper;
@Async("lotteryServiceExecutor")
public void saveLotteryRecord(String accountIp, LotteryItem lotteryItem, String prizeName) {
log.info(Thread.currentThread().getName() + "---saveLotteryRecord");
//存儲中獎信息
LotteryRecord record = new LotteryRecord();
record.setAccountIp(accountIp);
record.setItemId(lotteryItem.getId());
record.setPrizeName(prizeName);
record.setCreateTime(LocalDateTime.now());
lotteryRecordMapper.insert(record);
}
}
創建一個線程池：相關的配置信息是我們定義在YML文件中的數據。
@Configuration
@EnableAsync
@EnableConfigurationProperties(ThreadPoolExecutorProperties.class)
public class ThreadPoolExecutorConfig {
@Bean(name = "lotteryServiceExecutor")
public Executor lotteryServiceExecutor(ThreadPoolExecutorProperties poolExecutorProperties) {
ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
executor.setCorePoolSize(poolExecutorProperties.getCorePoolSize());
executor.setMaxPoolSize(poolExecutorProperties.getMaxPoolSize());
executor.setQueueCapacity(poolExecutorProperties.getQueueCapacity());
executor.setThreadNamePrefix(poolExecutorProperties.getNamePrefix());
executor.setRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy());
return executor;
}
}
@Data
@ConfigurationProperties(prefix = "async.executor.thread")
public class ThreadPoolExecutorProperties {
private int corePoolSize;
private int maxPoolSize;
private int queueCapacity;
private String namePrefix;
}
4.7 總結
以上便是整個項目的搭建，關於前端界面無非就是向後端發起請求，根據返回的獎品信息，將指針落在對應的轉盤位置處，具體代碼可以前往項目地址查看。希望大傢可以動個小手點點贊，嘻嘻。
5. 項目地址
如果直接使用項目的話，記得修改數據庫中活動的結束時間。
Redis
具體的實戰項目在lottery工程中。
到此這篇關於Redis 抽獎大轉盤的實戰示例的文章就介紹到這瞭,更多相關Redis 抽獎大轉盤內容請搜索WalkonNet以前的文章或繼續瀏覽下面的相關文章希望大傢以後多多支持WalkonNet！
推薦閱讀：
- springboot 集成redis哨兵主從的實現
- Springboot/Springcloud項目集成redis進行存取的過程解析
- Springboot整合Redis與數據持久化
- 使用Redis實現秒殺功能的簡單方法
- Java與SpringBoot對redis的使用方式