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Spring Boot集成

Salmon2026/1/15大约 3 分钟JavaCaffeine缓存本地缓存后端

Spring Boot集成

Spring Cache 简介

Spring Cache 是 Spring 提供的缓存抽象层，通过注解方式简化缓存操作。Spring Boot 2.x 默认使用 Caffeine 作为缓存实现。

快速集成

1. 添加依赖

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-cache</artifactId>
</dependency>
<dependency>
    <groupId>com.github.ben-manes.caffeine</groupId>
    <artifactId>caffeine</artifactId>
</dependency>

2. 启用缓存

@SpringBootApplication
@EnableCaching  // 启用缓存
public class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

3. 配置缓存

# application.yml
spring:
  cache:
    type: caffeine
    caffeine:
      spec: maximumSize=10000,expireAfterWrite=10m

4. 使用缓存注解

@Service
public class UserService {
    
    @Cacheable(value = "users", key = "#id")
    public User getById(Long id) {
        // 缓存未命中时执行
        return userRepository.findById(id).orElse(null);
    }
    
    @CachePut(value = "users", key = "#user.id")
    public User update(User user) {
        // 更新数据库并更新缓存
        return userRepository.save(user);
    }
    
    @CacheEvict(value = "users", key = "#id")
    public void delete(Long id) {
        // 删除数据库并清除缓存
        userRepository.deleteById(id);
    }
}

缓存注解详解

@Cacheable - 查询缓存

@Cacheable(
    value = "users",           // 缓存名称
    key = "#id",               // 缓存 key
    condition = "#id > 0",     // 缓存条件
    unless = "#result == null" // 排除条件
)
public User getById(Long id) {
    return userRepository.findById(id).orElse(null);
}

@CachePut - 更新缓存

@CachePut(value = "users", key = "#user.id")
public User update(User user) {
    return userRepository.save(user);
}

@CacheEvict - 删除缓存

// 删除单个
@CacheEvict(value = "users", key = "#id")
public void delete(Long id) {
    userRepository.deleteById(id);
}

// 删除所有
@CacheEvict(value = "users", allEntries = true)
public void deleteAll() {
    userRepository.deleteAll();
}

// 方法执行前删除
@CacheEvict(value = "users", key = "#id", beforeInvocation = true)
public void deleteBeforeInvocation(Long id) {
    userRepository.deleteById(id);
}

@Caching - 组合注解

@Caching(
    cacheable = {
        @Cacheable(value = "users", key = "#id")
    },
    evict = {
        @CacheEvict(value = "userList", allEntries = true)
    }
)
public User getById(Long id) {
    return userRepository.findById(id).orElse(null);
}

@CacheConfig - 类级别配置

@Service
@CacheConfig(cacheNames = "users")  // 类级别缓存名称
public class UserService {
    
    @Cacheable(key = "#id")  // 不需要再指定 value
    public User getById(Long id) {
        return userRepository.findById(id).orElse(null);
    }
}

自定义 CacheManager

单一缓存配置

@Configuration
@EnableCaching
public class CacheConfig {
    
    @Bean
    public CacheManager cacheManager() {
        CaffeineCacheManager cacheManager = new CaffeineCacheManager();
        cacheManager.setCaffeine(Caffeine.newBuilder()
            .maximumSize(10000)
            .expireAfterWrite(10, TimeUnit.MINUTES)
            .recordStats());
        return cacheManager;
    }
}

多缓存配置

不同业务使用不同的缓存配置：

@Configuration
@EnableCaching
public class CacheConfig {
    
    @Bean
    public CacheManager cacheManager() {
        SimpleCacheManager cacheManager = new SimpleCacheManager();
        
        List<CaffeineCache> caches = new ArrayList<>();
        
        // 用户缓存：容量大，过期时间长
        caches.add(new CaffeineCache("users",
            Caffeine.newBuilder()
                .maximumSize(10000)
                .expireAfterWrite(30, TimeUnit.MINUTES)
                .recordStats()
                .build()));
        
        // 配置缓存：容量小，过期时间短
        caches.add(new CaffeineCache("configs",
            Caffeine.newBuilder()
                .maximumSize(100)
                .expireAfterWrite(5, TimeUnit.MINUTES)
                .recordStats()
                .build()));
        
        // 热点缓存：容量中等，访问后过期
        caches.add(new CaffeineCache("hotData",
            Caffeine.newBuilder()
                .maximumSize(1000)
                .expireAfterAccess(10, TimeUnit.MINUTES)
                .recordStats()
                .build()));
        
        cacheManager.setCaches(caches);
        return cacheManager;
    }
}

配置文件方式

@Configuration
@EnableCaching
public class CacheConfig {
    
    @Value("${cache.users.max-size:10000}")
    private int usersMaxSize;
    
    @Value("${cache.users.expire-minutes:30}")
    private int usersExpireMinutes;
    
    @Bean
    public CacheManager cacheManager() {
        SimpleCacheManager cacheManager = new SimpleCacheManager();
        
        List<CaffeineCache> caches = new ArrayList<>();
        caches.add(new CaffeineCache("users",
            Caffeine.newBuilder()
                .maximumSize(usersMaxSize)
                .expireAfterWrite(usersExpireMinutes, TimeUnit.MINUTES)
                .build()));
        
        cacheManager.setCaches(caches);
        return cacheManager;
    }
}
# application.yml
cache:
  users:
    max-size: 10000
    expire-minutes: 30

缓存 Key 生成

SpEL 表达式

// 使用参数
@Cacheable(value = "users", key = "#id")

// 使用对象属性
@Cacheable(value = "users", key = "#user.id")

// 组合 key
@Cacheable(value = "users", key = "#type + ':' + #id")

// 使用方法
@Cacheable(value = "users", key = "#id.toString()")

// 使用 root 对象
@Cacheable(value = "users", key = "#root.methodName + ':' + #id")

自定义 KeyGenerator

@Configuration
public class CacheConfig {
    
    @Bean
    public KeyGenerator customKeyGenerator() {
        return (target, method, params) -> {
            StringBuilder sb = new StringBuilder();
            sb.append(target.getClass().getSimpleName());
            sb.append(":");
            sb.append(method.getName());
            sb.append(":");
            for (Object param : params) {
                sb.append(param.toString());
                sb.append("_");
            }
            return sb.toString();
        };
    }
}

// 使用
@Cacheable(value = "users", keyGenerator = "customKeyGenerator")
public User getById(Long id) {
    return userRepository.findById(id).orElse(null);
}

缓存统计监控

暴露统计端点

@RestController
@RequestMapping("/cache")
public class CacheController {
    
    @Autowired
    private CacheManager cacheManager;
    
    @GetMapping("/stats")
    public Map<String, Object> stats() {
        Map<String, Object> result = new HashMap<>();
        
        cacheManager.getCacheNames().forEach(name -> {
            Cache cache = cacheManager.getCache(name);
            if (cache != null) {
                com.github.benmanes.caffeine.cache.Cache<Object, Object> nativeCache = 
                    (com.github.benmanes.caffeine.cache.Cache<Object, Object>) cache.getNativeCache();
                
                CacheStats stats = nativeCache.stats();
                Map<String, Object> cacheStats = new HashMap<>();
                cacheStats.put("size", nativeCache.estimatedSize());
                cacheStats.put("hitRate", stats.hitRate());
                cacheStats.put("hitCount", stats.hitCount());
                cacheStats.put("missCount", stats.missCount());
                cacheStats.put("loadCount", stats.loadCount());
                cacheStats.put("evictionCount", stats.evictionCount());
                
                result.put(name, cacheStats);
            }
        });
        
        return result;
    }
    
    @DeleteMapping("/{name}")
    public void clearCache(@PathVariable String name) {
        Cache cache = cacheManager.getCache(name);
        if (cache != null) {
            cache.clear();
        }
    }
}

集成 Actuator

# application.yml
management:
  endpoints:
    web:
      exposure:
        include: caches,metrics
@Configuration
public class CacheMetricsConfig {
    
    @Bean
    public MeterBinder caffeineCacheMetrics(CacheManager cacheManager) {
        return registry -> {
            cacheManager.getCacheNames().forEach(name -> {
                Cache cache = cacheManager.getCache(name);
                if (cache != null) {
                    com.github.benmanes.caffeine.cache.Cache<?, ?> nativeCache = 
                        (com.github.benmanes.caffeine.cache.Cache<?, ?>) cache.getNativeCache();
                    CaffeineCacheMetrics.monitor(registry, nativeCache, name);
                }
            });
        };
    }
}

小结

Spring Boot 与 Caffeine 的集成非常简单，通过 @EnableCaching 和缓存注解即可快速使用。对于复杂场景，可以自定义 CacheManager 配置不同的缓存策略。

面试题预览

常见面试题

  1. Spring Cache 的常用注解有哪些？
  2. 如何为不同业务配置不同的缓存策略？
  3. @Cacheable 的 condition 和 unless 有什么区别？
最近更新:
贡献者: Salmon