详解Redis缓存与Mysql如何保证双写一致

@RestController
@RequestMapping
public class RedisController {


    @Autowired
    private RedisTemplate redisTemplate;
    @Autowired
    private SysUserMapper sysUserMapper;


    @GetMapping
    public void duobleCancle() throws InterruptedException {

        //删除缓存
        redisTemplate.delete("1");

        //获取数据
        SysUser sysUser = sysUserMapper.selectUserById(Long.valueOf(1));

        //更新数据
        SysUser updateSysUser =new SysUser();
        updateSysUser.setUserName("Lxlxxx");
        updateSysUser.setEmail("@163.com");

        UpdateWrapper<SysUser> updateWrapper = new UpdateWrapper();
        updateWrapper.eq("userId",1);

        sysUserMapper.update(updateSysUser,updateWrapper);

        //休眠时间这里的设定，是根据读业务的同步时间来设定的，这是一个大概的范围
        Thread.sleep(3000);

        //将读取的数据放入缓存
        redisTemplate.opsForValue().append(sysUser.getUserId(), JSON.toJSONString(sysUser));


        //第二次删除缓存
        //如果删除失败，缓存里面存的应该还是旧数据，后面线程读的还是旧数据，实际数据库已经是新数据了
        redisTemplate.delete("1");
    }

#编辑conf/canal.properties，修改MQ配置
canal.ip = 1 #canal服务器标识
canal.serverMode = rabbitmq # 指定rabbitmq
canal.mq.servers = 127.0.0.1 ##
canal.mq.vhost=canal  #MQ虚拟机名称
canal.mq.exchange=exchange.trade #交换机名称，用于将消息发送到绑定的队列
canal.mq.username=guest #MQ登录账号，注意要有上面vhost的权限
canal.mq.password=guest #MQ密码
---------------------------------------------------------------------------------
#编辑conf/example/instance.properties实例配置,配置数据库信息
canal.instance.dbUsername=root
canal.instance.dbPassword=123456
canal.instance.mysql.slaveId=1234 
canal.instance.master.address=127.0.0.1:3306 ## 数据库地址
canal.instance.defaultDatabaseName=test ## 数据库名
canal.mq.topic=example # 路由键，需要跟MQ中交换机队列的绑定路由key保持一致

#增加以下配置
log-bin=mysql-bin # 开启 binlog
binlog-format=ROW # 选择 ROW 模式
server_id=1 # 配置 

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
​
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-redis</artifactId>
        </dependency>
​
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-amqp</artifactId>
        </dependency>
​
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.3</version>
        </dependency>
                <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>${mybatis.plus.version}</version>
        </dependency>

spring:
  rabbitmq:
    virtual-host: canal
    host: 127.0.0.1
    publisher-confirms: true
  #数据源
  datasource:
    url: jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&characterEncoding=utf8&useSSL=false&serverTimezone=UTC
    username: root
    password: root
    driver-class-name: com.mysql.jdbc.Driver
  redis:
    host: 127.0.0.1
​

@Configuration
public class RabbitMqConfig {
    @Bean
    public Queue TestDirectQueue() {
        return new Queue("exchange.canal.queue",true);
    }
    //Direct交换机 起名：exchange.trade
    @Bean
    DirectExchange TestDirectExchange() {
        return new DirectExchange("exchange.canal");
    }
    //绑定  队列和交换机绑定
    @Bean
    Binding bindingDirect() {
        return BindingBuilder.bind(TestDirectQueue()).to(TestDirectExchange()).with("example");
    }
}

@Component
@Slf4j
public class RabbitMqListener {
    @Autowired
    private StringRedisTemplate redisTemplate;
    @RabbitListener(queues = "exchange.canal.queue")
    public void process(Message message) {
        log.info("canal queue消费的消息" + message.getBody());
        Map map = JSON.parseObject(message.getBody(), Map.class);
        JSONArray array = null;
        String sqlType = (String) map.get("type");
        //如果是查询,则去获取data数据
        if (StringUtils.endsWithIgnoreCase("SELECT", sqlType)) {
            array = JSONArray.parseArray((String) map.get("data"));
        }
        if (null == array) {
            return;
        }
        JSONObject jsonObject = array.getJSONObject(0);
        //如果是update、insert 其中一个则去更新缓存
        if (StringUtils.endsWithIgnoreCase("UPDATE", sqlType)
                || StringUtils.endsWithIgnoreCase("INSERT", sqlType)) {
            redisTemplate.boundValueOps(jsonObject.get("code").toString()).set(jsonObject.toString());
            //反之类型为"delete"则去删除缓存
        } else if (StringUtils.endsWithIgnoreCase("DELETE", sqlType)) {
            redisTemplate.delete(jsonObject.get("code").toString());
        }
        //查询到新的数据去更新缓存 ，反之再去删除对应的缓存，这里进行二次删除
        if (StringUtils.endsWithIgnoreCase("SELECT", sqlType)) {
            redisTemplate.boundValueOps(jsonObject.get("code").toString()).set(jsonObject.toString());
        } else {
            redisTemplate.delete(jsonObject.get("code").toString());
        }
    }
}