Redis操作--RedisTemplate（二）StringRedisTemplate

w_t_y_y2024-08-14 22:10

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
复制代码 
 @Autowired
    private StringRedisTemplate stringRedisTemplate;

    @Test
    public 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
复制代码 
    @Autowired
    private StringRedisTemplate stringRedisTemplate;    
   
    @Test
    public 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：

复制代码 
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

复制代码 
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 {

    @Override
    public 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 {

    @Override
    public 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

复制代码 
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 {

    @Autowired
    private RedisBroadcastUserMsgHandler userMsgHandler;

    @Autowired
    private RedisBroadcastUserMsgTwoHandler twoHandler;

    @Bean
    public 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

复制代码 
    @Autowired
    private StringRedisTemplate stringRedisTemplate;  

    @Test
    public 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：

复制代码 
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：

复制代码 
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 {



    @Override
    public String getTopic() {
        return "user-topic";
    }

    @Override
    public 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 {

    @Override
    public 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);
    }

    @Override
    public String getTopic() {
        return "user-topic-two";
    }
}

（2）注册监听器：

复制代码 
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 {

    @Autowired
    private RedisBroadcastUserMsgHandler userMsgHandler;

    @Autowired
    private List<RedisListener> redisListeners;

    @Bean
    public 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：

复制代码 
@Test
    public 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：

复制代码 
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)
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