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springboot整合redis之消息隊列

 更新時間:2022年06月29日 16:10:01   作者:yololee_  
本文主要介紹了springboot整合redis之消息隊列,文中通過示例代碼介紹的非常詳細,對大家的學習或者工作具有一定的參考學習價值,需要的朋友們下面隨著小編來一起學習學習吧

一、項目準備

依賴

        <!-- RedisTemplate -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-redis</artifactId>
        </dependency>
        <!-- Redis-Jedis -->
        <dependency>
            <groupId>redis.clients</groupId>
            <artifactId>jedis</artifactId>
            <version>2.9.0</version>
        </dependency>

application.yaml配置文件

spring:
  redis:
    host: 127.0.0.1
    port: 6379
    database: 0
    timeout: 4000
    jedis:
      pool:
        max-wait: -1
        max-active: -1
        max-idle: 20
        min-idle: 10

二、配置類

public class ObjectMapperConfig {

    public static final ObjectMapper objectMapper;
    private static final String PATTERN = "yyyy-MM-dd HH:mm:ss";

    static {
        JavaTimeModule javaTimeModule = new JavaTimeModule();
        javaTimeModule.addSerializer(LocalDateTime.class, new LocalDateTimeSerializer());
        javaTimeModule.addDeserializer(LocalDateTime.class, new LocalDateTimeDeserializer());
        objectMapper = new ObjectMapper()
                // 轉(zhuǎn)換為格式化的json(控制臺打印時,自動格式化規(guī)范)
                //.enable(SerializationFeature.INDENT_OUTPUT)
                // Include.ALWAYS  是序列化對像所有屬性(默認)
                // Include.NON_NULL 只有不為null的字段才被序列化,屬性為NULL 不序列化
                // Include.NON_EMPTY 如果為null或者 空字符串和空集合都不會被序列化
                // Include.NON_DEFAULT 屬性為默認值不序列化
                .setSerializationInclusion(JsonInclude.Include.NON_NULL)
                // 如果是空對象的時候,不拋異常
                .configure(SerializationFeature.FAIL_ON_EMPTY_BEANS, false)
                // 反序列化的時候如果多了其他屬性,不拋出異常
                .configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false)
                // 取消時間的轉(zhuǎn)化格式,默認是時間戳,可以取消,同時需要設(shè)置要表現(xiàn)的時間格式
                .configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false)
                .setDateFormat(new SimpleDateFormat(PATTERN))
                // 對LocalDateTime序列化跟反序列化
                .registerModule(javaTimeModule)

                .setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY)
                // 此項必須配置,否則會報java.lang.ClassCastException: java.util.LinkedHashMap cannot be cast to XXX
                .enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL, JsonTypeInfo.As.PROPERTY)
        ;
    }

    static class LocalDateTimeSerializer extends JsonSerializer<LocalDateTime> {
        @Override
        public void serialize(LocalDateTime value, JsonGenerator gen, SerializerProvider serializers) throws IOException {
            gen.writeString(value.format(DateTimeFormatter.ofPattern(PATTERN)));
        }
    }

    static class LocalDateTimeDeserializer extends JsonDeserializer<LocalDateTime> {
        @Override
        public LocalDateTime deserialize(JsonParser p, DeserializationContext deserializationContext) throws IOException {
            return LocalDateTime.parse(p.getValueAsString(), DateTimeFormatter.ofPattern(PATTERN));
        }
    }

}
@Configuration
public class RedisConfig {

    /**
     * redisTemplate配置
     */
    @Bean
    public RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory factory) {
        RedisTemplate<String, Object> template = new RedisTemplate<>();
        // 配置連接工廠
        template.setConnectionFactory(factory);

        //使用Jackson2JsonRedisSerializer來序列化和反序列化redis的value值(默認使用JDK的序列化方式)
        Jackson2JsonRedisSerializer<Object> jacksonSerializer = new Jackson2JsonRedisSerializer<>(Object.class);
        jacksonSerializer.setObjectMapper(ObjectMapperConfig.objectMapper);
        StringRedisSerializer stringRedisSerializer = new StringRedisSerializer();

        // 使用StringRedisSerializer來序列化和反序列化redis的key,value采用json序列化
        template.setKeySerializer(stringRedisSerializer);
        template.setValueSerializer(jacksonSerializer);

        // 設(shè)置hash key 和value序列化模式
        template.setHashKeySerializer(stringRedisSerializer);
        template.setHashValueSerializer(jacksonSerializer);
        template.afterPropertiesSet();

        return template;
    }
}

三、redis中l(wèi)ist數(shù)據(jù)類型

在Redis中,List類型是按照插入順序排序的字符串鏈表。和數(shù)據(jù)結(jié)構(gòu)中的普通鏈表一樣,我們可以在其頭部和尾部添加新的元素

優(yōu)勢:

  • 順序排序,保證先進先出
  • 隊列為空時,自動從Redis數(shù)據(jù)庫刪除
  • 在隊列的兩頭插入或刪除元素,效率極高,即使隊列中元素達到百萬級
  • List中可以包含的最大元素數(shù)量是4294967295

定時器監(jiān)聽隊列

生產(chǎn)者

@Slf4j
@Component
public class MessageProducer {

    public static final String MESSAGE_KEY = "message:queue";

    @Autowired
    private RedisTemplate<String,Object> redisTemplate;

    public void lPush() {
        for (int i = 0; i < 10; i++) {
            new Thread(() -> {
                Long size = redisTemplate.opsForList().leftPush(MESSAGE_KEY, Thread.currentThread().getName() + ":hello world");
                log.info(Thread.currentThread().getName() + ":put message size = " + size);
            }).start();
        }
    }
}

消費者:消費消息,定時器以達到監(jiān)聽隊列功能

@Slf4j
@Component
@EnableScheduling
public class MessageConsumer {

    public static final String MESSAGE_KEY = "message:queue";

    @Autowired
    private RedisTemplate<String,Object> redisTemplate;

    @Scheduled(initialDelay = 5 * 1000, fixedRate = 2 * 1000)
    public void rPop() {
        String message = (String) redisTemplate.opsForList().rightPop(MESSAGE_KEY);
        log.info(message);
    }
}
@RestController
public class RedisController {

    @Autowired
    private MessageProducer messageProducer;

    @GetMapping("/lPush")
    public void lPush() {
        messageProducer.lPush();
    }
}

測試

http://localhost:8080/lPush

可能出現(xiàn)的問題:

1.通過定時器監(jiān)聽List中是否有待處理消息,每執(zhí)行一次都會發(fā)起一次連接,這會造成不必要的浪費。

2.生產(chǎn)速度大于消費速度,隊列堆積,消息時效性差,占用內(nèi)存。

運行即監(jiān)控隊列

修改消息消費者代碼。

當隊列沒有元素時,會阻塞10秒,然后再次監(jiān)聽隊列,
需要注意的是,阻塞時間必須小于連接超時時間

@Slf4j
@Component
@EnableScheduling
public class MessageConsumer {

    public static final String MESSAGE_KEY = "message:queue";

    @Autowired
    private RedisTemplate<String,Object> redisTemplate;

    //@Scheduled(initialDelay = 5 * 1000, fixedRate = 2 * 1000)
    public void rPop() {
        String message = (String) redisTemplate.opsForList().rightPop(MESSAGE_KEY);
        log.info(message);
    }

    @PostConstruct
    public void brPop() {
        new Thread(() -> {
            while (true) {
                String message = (String) redisTemplate.opsForList().rightPop(MESSAGE_KEY, 10, TimeUnit.SECONDS);
                log.info(message);
            }
        }).start();
    }
}

阻塞時間不能為負,直接報錯超時為負
阻塞時間為零,此時阻塞時間等于超時時間,最后報錯連接超時
阻塞時間大于超時時間,報錯連接超時

測試:

消息不可重復(fù)消費,因為消息從隊列POP之后就被移除了,即不支持多個消費者消費同一批數(shù)據(jù)

消息丟失,消費期間發(fā)生異常,消息未能正常消費

四、發(fā)布/訂閱模式

消息可以重復(fù)消費,多個消費者訂閱同一頻道即可

一個消費者根據(jù)匹配規(guī)則訂閱多個頻道

消費者只能消費訂閱之后發(fā)布的消息,這意味著,消費者下線再上線這期間發(fā)布的消息將會丟失

數(shù)據(jù)不具有持久化。同樣Redis宕機也會數(shù)據(jù)丟失

消息發(fā)布后,是推送到一個緩沖區(qū)(內(nèi)存),消費者從緩沖區(qū)拉取消息,當消息堆積,緩沖區(qū)溢出,消費者就會被迫下線,同時釋放對應(yīng)的緩沖區(qū)

RedisConfig中添加監(jiān)聽器

    /**
     * redis消息監(jiān)聽器容器
     */
    @Bean
    public RedisMessageListenerContainer container(RedisConnectionFactory connectionFactory) {
        RedisMessageListenerContainer container = new RedisMessageListenerContainer();
        container.setConnectionFactory(connectionFactory);

        //訂閱頻道,通配符*表示任意多個占位符
        container.addMessageListener(new MySubscribe(), new PatternTopic("channel*"));

        return container;
    }

訂閱者

package com.yzm.redis08.message;

import org.springframework.data.redis.connection.Message;
import org.springframework.data.redis.connection.MessageListener;

public class MySubscribe implements MessageListener {

    @Override
    public void onMessage(Message message, byte[] bytes) {
        System.out.println("訂閱頻道:" + new String(message.getChannel()));
        System.out.println("接收數(shù)據(jù):" + new String(message.getBody()));
    }
}

消息發(fā)布

    @GetMapping("/publish")
    public void publish() {
        redisTemplate.convertAndSend("channel_first", "hello world");
    }

另一種發(fā)布方式

    /**
     * redis消息監(jiān)聽器容器
     */
    @Bean
    public RedisMessageListenerContainer container(RedisConnectionFactory connectionFactory) {
        RedisMessageListenerContainer container = new RedisMessageListenerContainer();
        container.setConnectionFactory(connectionFactory);

        //訂閱頻道,通配符*表示任意多個占位符
        container.addMessageListener(new MySubscribe(), new PatternTopic("channel*"));
        // 通配符?:表示一個占位符
        MessageListenerAdapter listenerAdapter = new MessageListenerAdapter(new MySubscribe2(), "getMessage");
        listenerAdapter.afterPropertiesSet();
        container.addMessageListener(listenerAdapter, new PatternTopic("channel?"));

        return container;
    }
public class MySubscribe2 {

    public void getMessage(Object message, String channel) {
        System.out.println("訂閱頻道2:" + channel);
        System.out.println("接收數(shù)據(jù)2:" + message);
    }
}
    @GetMapping("/publish2")
    public void publish2() {
        redisTemplate.convertAndSend("channel2", "hello world");
    }

消息是實體對象,進行轉(zhuǎn)換

@Data
@Builder
@NoArgsConstructor
@AllArgsConstructor
public class User implements Serializable {
    private static final long serialVersionUID = 5250232737975907491L;
    private Integer id;
    private String username;
}
public class MySubscribe3 implements MessageListener {

    @Override
    public void onMessage(Message message, byte[] bytes) {
        Jackson2JsonRedisSerializer<User> jacksonSerializer = new Jackson2JsonRedisSerializer<>(User.class);
        jacksonSerializer.setObjectMapper(ObjectMapperConfig.objectMapper);
        User user = jacksonSerializer.deserialize(message.getBody());
        
        System.out.println("訂閱頻道3:" + new String(message.getChannel()));
        System.out.println("接收數(shù)據(jù)3:" + user);
    }
}
    /**
     * redis消息監(jiān)聽器容器
     */
    @Bean
    public RedisMessageListenerContainer container(RedisConnectionFactory connectionFactory) {
        RedisMessageListenerContainer container = new RedisMessageListenerContainer();
        container.setConnectionFactory(connectionFactory);

        //訂閱頻道,通配符*:表示任意多個占位符
        container.addMessageListener(new MySubscribe(), new PatternTopic("channel*"));
        // 通配符?:表示一個占位符
        MessageListenerAdapter listenerAdapter = new MessageListenerAdapter(new MySubscribe2(), "getMessage");
        listenerAdapter.afterPropertiesSet();
        container.addMessageListener(listenerAdapter, new PatternTopic("channel?"));

        container.addMessageListener(new MySubscribe3(), new PatternTopic("user"));

        return container;
    }

    @GetMapping("/publish3")
    public void publish3() {
        User user = User.builder().id(1).username("yzm").build();
        redisTemplate.convertAndSend("user", user);
    }

五、ZSet實現(xiàn)延遲隊列

生產(chǎn)消息,score = 時間搓+60s隨機數(shù)

    public static final String MESSAGE_ZKEY = "message:ZSetqueue";
    public volatile AtomicInteger count =  new AtomicInteger();
    public void zAdd() {
        for (int i = 0; i < 10; i++) {
            new Thread(() -> {
                int increment = count.getAndIncrement();
                log.info(Thread.currentThread().getName() + ":put message to zset = " + increment);
                double score = System.currentTimeMillis() + new Random().nextInt(60 * 1000);
                redisTemplate.opsForZSet().add(MESSAGE_ZKEY, Thread.currentThread().getName() + " hello zset:" + increment, score);
            }).start();
        }
    }

消費者:定時任務(wù),每秒執(zhí)行一次

    public static final String MESSAGE_ZKEY = "message:ZSetqueue";
    public SimpleDateFormat simpleDateFormat = new SimpleDateFormat();
    @Scheduled(initialDelay = 5 * 1000, fixedRate = 1000)
    public void zrangebysocre() {
        log.info("延時隊列消費。。。");
        // 拉取score小于當前時間戳的消息
        Set<Object> messages = redisTemplate.opsForZSet().rangeByScore(MESSAGE_ZKEY, 0, System.currentTimeMillis());
        if (messages != null) {
            for (Object message : messages) {
                Double score = redisTemplate.opsForZSet().score(MESSAGE_ZKEY, message);
                log.info("消費了:" + message + "消費時間為:" + simpleDateFormat.format(score));
                redisTemplate.opsForZSet().remove(MESSAGE_ZKEY, message);
            }
        }
    }
    @GetMapping("/zadd")
    public void zadd() {
        messageProducer.zAdd();
    }

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