springboot整合redis之消息队列
目录
- 一、项目准备
- 二、配置类
- 三、redis中list数据类型
- 定时器监听队列
- 运行即监控队列
- 四、发布/订阅模式
- 五、ZSet实现延迟队列
一、项目准备
依赖
<!-- 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、配置类
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() // 转换为格式化的json(控制台打印时,自动格式化规范) //.enable(SerializationFeature.INDENT_OUTPUT) // Include.ALWAYS 是序列化对像所有属性(默认) // Include.NON_NULL 只有不为null的字段才被序列化,属性为NULL 不序列化 // Include.NON_EMPTY 如果为null或者 空字符串和空集合都不会被序列化 // Include.NON_DEFAULT 属性为默认值不序列化 .setSerializationInclusion(JsonInclude.Include.NON_NULL) // 如果是空对象的时候,不抛异常 .configure(SerializationFeature.FAIL_ON_EMPTY_BEANS, false) // 反序列化的时候如果多了其他属性,不抛出异常 .configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false) // 取消时间的转化格式,默认是时间戳,可以取消,同时需要设置要表现的时间格式 .configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false) .setDateFormat(new SimpleDateFormat(PATTERN)) // 对LocalDateTime序列化跟反序列化 .registerModule(javaTimeModule) .setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY) // 此项必须配置,否则会报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<>(); // 配置连接工厂 template.setConnectionFactory(factory); //使用Jackson2JsonRedisSerializer来序列化和反序列化redis的value值(默认使用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来序列化和反序列化redis的key,value采用json序列化 template.setKeySerializer(stringRedisSerializer); template.setValueSerializer(jacksonSerializer); // 设置hash key 和value序列化模式 template.setHashKeySerializer(stringRedisSerializer); template.setHashValueSerializer(jacksonSerializer); template.afterPropertiesSet(); return template; } }
三、redis中list数据类型
在Redis中,List类型是按照插入顺序排序的字符串链表。和数据结构中的普通链表一样,我们可以在其头部和尾部添加新的元素
优势:
- 顺序排序,保证先进先出
- 队列为空时,自动从Redis数据库删除
- 在队列的两头插入或删除元素,效率极高,即使队列中元素达到百万级
- List中可以包含的最大元素数量是4294967295
定时器监听队列
生产者
@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(); } } }
消费者:消费消息,定时器以达到监听队列功能
@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(); } }
测试
http://localhost:8080/lPush
可能出现的问题:
1.通过定时器监听List中是否有待处理消息,每执行一次都会发起一次连接,这会造成不必要的浪费。
2.生产速度大于消费速度,队列堆积,消息时效性差,占用内存。
运行即监控队列
修改消息消费者代码。
当队列没有元素时,会阻塞10秒,然后再次监听队列,
需要注意的是,阻塞时间必须小于连接超时时间
@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(); } }
阻塞时间不能为负,直接报错超时为负
阻塞时间为零,此时阻塞时间等于超时时间,最后报错连接超时
阻塞时间大于超时时间,报错连接超时
测试:
消息不可重复消费,因为消息从队列POP之后就被移除了,即不支持多个消费者消费同一批数据
消息丢失,消费期间发生异常,消息未能正常消费
四、发布/订阅模式
消息可以重复消费,多个消费者订阅同一频道即可
一个消费者根据匹配规则订阅多个频道
消费者只能消费订阅之后发布的消息,这意味着,消费者下线再上线这期间发布的消息将会丢失
数据不具有持久化。同样Redis宕机也会数据丢失
消息发布后,是推送到一个缓冲区(内存),消费者从缓冲区拉取消息,当消息堆积,缓冲区溢出,消费者就会被迫下线,同时释放对应的缓冲区
RedisConfig中添加监听器
/** * redis消息监听器容器 */ @Bean public RedisMessageListenerContainer container(RedisConnectionFactory connectionFactory) { RedisMessageListenerContainer container = new RedisMessageListenerContainer(); container.setConnectionFactory(connectionFactory); //订阅频道,通配符*表示任意多个占位符 container.addMessageListener(new MySubscribe(), new PatternTopic("channel*")); return container; }
订阅者
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("订阅频道:" + new String(message.getChannel())); System.out.println("接收数据:" + new String(message.getBody())); } }
消息发布
@GetMapping("/publish") public void publish() { redisTemplate.convertAndSend("channel_first", "hello world"); }
另一种发布方式
/** * redis消息监听器容器 */ @Bean public RedisMessageListenerContainer container(RedisConnectionFactory connectionFactory) { RedisMessageListenerContainer container = new RedisMessageListenerContainer(); container.setConnectionFactory(connectionFactory); //订阅频道,通配符*表示任意多个占位符 container.addMessageListener(new MySubscribe(), new PatternTopic("channel*")); // 通配符?:表示一个占位符 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("订阅频道2:" + channel); System.out.println("接收数据2:" + message); } }
@GetMapping("/publish2") public void publish2() { redisTemplate.convertAndSend("channel2", "hello world"); }
消息是实体对象,进行转换
@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("订阅频道3:" + new String(message.getChannel())); System.out.println("接收数据3:" + user); } }
/** * redis消息监听器容器 */ @Bean public RedisMessageListenerContainer container(RedisConnectionFactory connectionFactory) { RedisMessageListenerContainer container = new RedisMessageListenerContainer(); container.setConnectionFactory(connectionFactory); //订阅频道,通配符*:表示任意多个占位符 container.addMessageListener(new MySubscribe(), new PatternTopic("channel*")); // 通配符?:表示一个占位符 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实现延迟队列
生产消息,score = 时间搓+60s随机数
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(); } }
消费者:定时任务,每秒执行一次
public static final String MESSAGE_ZKEY = "message:ZSetqueue"; public SimpleDateFormat simpleDateFormat = new SimpleDateFormat(); @Scheduled(initialDelay = 5 * 1000, fixedRate = 1000) public void zrangebysocre() { log.info("延时队列消费。。。"); // 拉取score小于当前时间戳的消息 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("消费了:" + message + "消费时间为:" + simpleDateFormat.format(score)); redisTemplate.opsForZSet().remove(MESSAGE_ZKEY, message); } } }
@GetMapping("/zadd") public void zadd() { messageProducer.zAdd(); }
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