spring boot中如何保证redis和mysql缓存一致性呢?

保证redis和mysql一致性的实现思路

1.为程序配置redisTemplate
2.操作数据库
    操作完毕后,立即同步redis,使用以上方式即可保证mysql和redis的数据一致性

步骤一
  添加依赖
   在pom.xml文件中
      添加Spring Boot、Spring Data JPA、Redis和相关依赖

<dependencies>
    <!-- Spring Boot Starter -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-redis</artifactId>
    </dependency>
    <!-- MySQL Connector -->
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
    </dependency>
</dependencies>

步骤二
  配置MySQL和Redis连接

在application.properties
  或
  application.yml中配置MySQL和Redis的连接信息：
 
# MySQL Configuration
spring.datasource.url=jdbc:mysql://localhost:3306/mydb
spring.datasource.username=dbuser
spring.datasource.password=dbpass
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver

# Redis Configuration
spring.redis.host=localhost
spring.redis.port=6379

步骤三
   创建实体类和Repository 

@Entity
public class Product {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    private String name;

    // Getters and Setters
}

public interface ProductRepository extends JpaRepository<Product, Long> {
    // Custom queries if needed
}

步骤四
   配置缓存

   在application.properties
   或
    application.yml中配置Spring Cache，指定使用Redis作为缓存：
 # Cache Configuration
spring.cache.type=redis

步骤五 
  使用缓存

    在Service层使用Spring Cache注解
      例
       @Cacheable
       来缓存数据

import org.springframework.cache.annotation.Cacheable;
import org.springframework.stereotype.Service;

@Service
public class ProductService {

    private final ProductRepository productRepository;

    public ProductService(ProductRepository productRepository) {
        this.productRepository = productRepository;
    }

    @Cacheable("products")
    public Product getProductById(Long productId) {
        return productRepository.findById(productId).orElse(null);
    }
}

步骤六
  手动同步缓存和数据库
   在Service层进行手动同步缓存和数据库
     确保缓存和数据库的一致性
     
import org.springframework.cache.CacheManager;
import org.springframework.stereotype.Service;

@Service
public class CacheSyncService {

    private final CacheManager cacheManager;
    private final ProductRepository productRepository;

    public CacheSyncService(CacheManager cacheManager, ProductRepository productRepository) {
        this.cacheManager = cacheManager;
        this.productRepository = productRepository;
    }

    public void syncProductCache(Long productId) {
        // Manually evict cache for the specified product ID
        cacheManager.getCache("products").evict(productId);

        // Retrieve product from the database and update the cache
        Product product = productRepository.findById(productId).orElse(null);
        if (product != null) {
            cacheManager.getCache("products").put(productId, product);
        }
    }
}

步骤七
  使用示例
   在应用中使用ProductService获取产品
     同时使用CacheSyncService进行手动同步：
 
@Service
public class ExampleService {

    private final ProductService productService;
    private final CacheSyncService cacheSyncService;

    public ExampleService(ProductService productService, CacheSyncService cacheSyncService) {
        this.productService = productService;
        this.cacheSyncService = cacheSyncService;
    }

    public Product getProductById(Long productId) {
        // Try to get product from cache
        Product product = productService.getProductById(productId);

        // If not found in cache, manually sync cache and get from database
        if (product == null) {
            cacheSyncService.syncProductCache(productId);
            product = productService.getProductById(productId);
        }

        return product;
    }
}