Redis操作--RedisTemplate（二）StringRedisTemplate

一、介绍

1、简介

由于存储在 Redis 中的 key 和 value 通常是很常见的 String 类型，Redis模块提供了 RedisConnection 和 RedisTemplate 的扩展，分是 StringRedisConnection 和 StringRedisTemplate，作为字符串操作的解决方案。

通过源码可以看见对于Key、Value、HashKey、HashValue都是进行String类型的序列化。

因此对于一些复杂类型，如对象在StringRedisTemplate的时候往往需要自己手动序列化将对象转为JSON再存入Redis。

二、集成

使用StringRedisTemplate，不需要（写RedisConfig）额外设置序列化。不过存取对象需要自己序列化、反序列化。

三、使用

1、存取string

 @Autowiredprivate StringRedisTemplate stringRedisTemplate;@Testpublic void  testString(){String key = "string-name";//存String value = "这是value123";stringRedisTemplate.opsForValue().set(key,value);//取Object valueObj = stringRedisTemplate.opsForValue().get(key);System.out.println("value为：" + valueObj);}

输出：value为：这是value123，

查看可视化工具也没有乱码

2、存取对象

    @Autowiredprivate StringRedisTemplate stringRedisTemplate;    @Testpublic void  testUser(){String key = "user-key";//存UserDTO userDTO = new UserDTO();userDTO.setUserAccount("zhangsan");userDTO.setAge(18);userDTO.setUserName("张三");stringRedisTemplate.opsForValue().set(key, JSON.toJSONString(userDTO));//取String valueObj = stringRedisTemplate.opsForValue().get(key);UserDTO redisUser = JSON.parseObject(valueObj, UserDTO.class);System.out.println("value为：" + redisUser);}

输出：value为：UserDTO(userName=张三, age=18, userAccount=zhangsan)

查看可视化工具没有乱码：

3、广播消息

（1）发送消息：

stringRedisTemplate.convertAndSend

（2）接收消息：

① implements MessageListener来实现一个监听器；

② 注册监听器到RedisMessageListenerContainer中。

demo：

（1）监听器：如我有两个监听器

package org.example.listen;import com.alibaba.fastjson.JSON;
import lombok.extern.slf4j.Slf4j;
import org.example.dto.UserDTO;
import org.springframework.data.redis.connection.Message;
import org.springframework.data.redis.connection.MessageListener;
import org.springframework.data.redis.serializer.RedisSerializer;
import org.springframework.stereotype.Component;@Slf4j
@Component
public class RedisBroadcastUserMsgHandler implements MessageListener {@Overridepublic void onMessage(Message message, byte[] pattern) {String consumerChannel = RedisSerializer.string().deserialize(message.getChannel());if(!consumerChannel.equals("user-topic")){return;}byte[] body = message.getBody();String json = RedisSerializer.string().deserialize(body);UserDTO userDTO = JSON.parseObject(json,UserDTO.class);log.info("handle接收到："+userDTO);}
}

package org.example.listen;import com.alibaba.fastjson.JSON;
import lombok.extern.slf4j.Slf4j;
import org.example.dto.UserDTO;
import org.springframework.data.redis.connection.Message;
import org.springframework.data.redis.connection.MessageListener;
import org.springframework.data.redis.serializer.RedisSerializer;
import org.springframework.stereotype.Component;@Slf4j
@Component
public class RedisBroadcastUserMsgTwoHandler implements MessageListener {@Overridepublic void onMessage(Message message, byte[] pattern) {String consumerChannel = RedisSerializer.string().deserialize(message.getChannel());if(!consumerChannel.equals("user-topic-two")){return;}byte[] body = message.getBody();String json = RedisSerializer.string().deserialize(body);UserDTO userDTO = JSON.parseObject(json,UserDTO.class);log.info("handle接收到："+userDTO);}
}

（2）注册监听器

package org.example.config;import lombok.extern.slf4j.Slf4j;
import org.example.listen.RedisBroadcastUserMsgHandler;
import org.example.listen.RedisBroadcastUserMsgTwoHandler;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.connection.MessageListener;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.listener.ChannelTopic;
import org.springframework.data.redis.listener.RedisMessageListenerContainer;import java.util.List;@Slf4j
@Configuration
public class RedisListenerConfig {@Autowiredprivate RedisBroadcastUserMsgHandler userMsgHandler;@Autowiredprivate RedisBroadcastUserMsgTwoHandler twoHandler;@Beanpublic RedisMessageListenerContainer redisContainer(RedisConnectionFactory connectionFactory) {RedisMessageListenerContainer container = new RedisMessageListenerContainer();container.setConnectionFactory(connectionFactory);container.addMessageListener(userMsgHandler, new ChannelTopic("user-topic"));container.addMessageListener(twoHandler, new ChannelTopic("user-topic-two"));return container;}
}

（3）发送消息

    @Autowiredprivate StringRedisTemplate stringRedisTemplate;  @Testpublic void  testSendMsg(){UserDTO userDTO = new UserDTO();userDTO.setUserAccount("zhangsan");userDTO.setAge(18);userDTO.setUserName("张三");String channel = "user-topic";stringRedisTemplate.convertAndSend(channel,JSON.toJSONString(userDTO));//String channelTwo = "user-topic-two";stringRedisTemplate.convertAndSend(channelTwo,JSON.toJSONString(userDTO));}

执行控制台打印：

2024-08-13T16:04:31.630+08:00  INFO 10496 --- [edisContainer-2] o.e.l.RedisBroadcastUserMsgTwoHandler    : handle接收到：UserDTO(userName=张三, age=18, userAccount=zhangsan)
2024-08-13T16:04:31.630+08:00  INFO 10496 --- [edisContainer-1] o.e.listen.RedisBroadcastUserMsgHandler  : handle接收到：UserDTO(userName=张三, age=18, userAccount=zhangsan)

改进demo

如果有多个消费者，注册会比较麻烦，因此对上述监听器代码封装下：

（1）监听器：

package org.example.listen;import org.springframework.data.redis.connection.MessageListener;public abstract class RedisListener implements MessageListener {public abstract String getTopic();
}

package org.example.listen;import com.alibaba.fastjson.JSON;
import lombok.extern.slf4j.Slf4j;
import org.example.dto.UserDTO;
import org.springframework.data.redis.connection.Message;
import org.springframework.data.redis.connection.MessageListener;
import org.springframework.data.redis.serializer.RedisSerializer;
import org.springframework.stereotype.Component;@Slf4j
@Component
public class RedisBroadcastUserMsgHandler extends RedisListener {@Overridepublic String getTopic() {return "user-topic";}@Overridepublic void onMessage(Message message, byte[] pattern) {byte[] body = message.getBody();String json = RedisSerializer.string().deserialize(body);UserDTO userDTO = JSON.parseObject(json,UserDTO.class);log.info("handle接收到："+userDTO);}
}

package org.example.listen;import com.alibaba.fastjson.JSON;
import lombok.extern.slf4j.Slf4j;
import org.example.dto.UserDTO;
import org.springframework.data.redis.connection.Message;
import org.springframework.data.redis.connection.MessageListener;
import org.springframework.data.redis.serializer.RedisSerializer;
import org.springframework.stereotype.Component;@Slf4j
@Component
public class RedisBroadcastUserMsgTwoHandler extends RedisListener {@Overridepublic void onMessage(Message message, byte[] pattern) {byte[] body = message.getBody();String json = RedisSerializer.string().deserialize(body);UserDTO userDTO = JSON.parseObject(json,UserDTO.class);log.info("handle接收到："+userDTO);}@Overridepublic String getTopic() {return "user-topic-two";}
}

（2）注册监听器：

package org.example.config;import lombok.extern.slf4j.Slf4j;
import org.example.listen.RedisBroadcastUserMsgHandler;
import org.example.listen.RedisBroadcastUserMsgTwoHandler;
import org.example.listen.RedisListener;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.connection.MessageListener;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.listener.ChannelTopic;
import org.springframework.data.redis.listener.RedisMessageListenerContainer;import java.util.List;@Slf4j
@Configuration
public class RedisListenerConfig {@Autowiredprivate RedisBroadcastUserMsgHandler userMsgHandler;@Autowiredprivate List<RedisListener> redisListeners;@Beanpublic RedisMessageListenerContainer redisContainer(RedisConnectionFactory connectionFactory) {RedisMessageListenerContainer container = new RedisMessageListenerContainer();container.setConnectionFactory(connectionFactory);for(RedisListener listener : redisListeners) {container.addMessageListener(listener, new ChannelTopic(listener.getTopic()));}return container;}
}

执行Test：

@Testpublic void  testSendMsg(){UserDTO userDTO = new UserDTO();userDTO.setUserAccount("zhangsan");userDTO.setAge(18);userDTO.setUserName("张三");String channel = "user-topic";stringRedisTemplate.convertAndSend(channel,JSON.toJSONString(userDTO));//userDTO.setUserAccount("zhangsan-two");userDTO.setUserName("张三-two");String channelTwo = "user-topic-two";stringRedisTemplate.convertAndSend(channelTwo,JSON.toJSONString(userDTO));}

打印：

2024-08-13T16:25:10.725+08:00  INFO 88872 --- [edisContainer-1] o.e.listen.RedisBroadcastUserMsgHandler  : handle接收到：UserDTO(userName=张三, age=18, userAccount=zhangsan)
2024-08-13T16:25:10.725+08:00  INFO 88872 --- [edisContainer-2] o.e.l.RedisBroadcastUserMsgTwoHandler    : handle接收到：UserDTO(userName=张三-two, age=18, userAccount=zhangsan-two)