java实现本地缓存的示例代码

 <dependency><dependency>
    <groupId>com.google.guava</groupId>
    <artifactId>guava</artifactId>
    <version>31.1-jre</version>
</dependency>

@Slf4j
public class GuavaCacheTest {
    public static void main(String[] args) throws ExecutionException {
        Cache<String, String> cache = CacheBuilder.newBuilder()
                .initialCapacity(5)  // 初始容量
                .maximumSize(10)   // 缓存的最大数量，超过该数量将被淘汰
                .expireAfterWrite(60, TimeUnit.SECONDS) // 过期时间
                .build();

        String orderId = String.valueOf(123456789);
        String orderInfo = cache.get(orderId, () -> getInfo(orderId));
        log.info("orderInfo = {}", orderInfo);

    }

    private static String getInfo(String orderId) {
        String info = "";
        // 首先查redis
        log.info("get data from redis");
        // redis不存在 查db
        log.info("get data from mysql");
        info = String.format("{orderId=%s}", orderId);
        return info;
    }
}

 <dependency><dependency>
    <groupId>org.ehcache</groupId>
    <artifactId>ehcache</artifactId>
    <version>3.9.7</version>
</dependency>

@Slf4j
public class EhcacheTest {
    private static final String ORDER_CACHE = "orderCache";
    public static void main(String[] args) {
        CacheManager cacheManager = CacheManagerBuilder.newCacheManagerBuilder()
                // 创建实例
                .withCache(ORDER_CACHE, CacheConfigurationBuilder
              // 声明一个容量为20的堆内缓存
                        .newCacheConfigurationBuilder(String.class, String.class, ResourcePoolsBuilder.heap(20)))
                .build(true);
        // 得到缓存实例
        Cache<String, String> cache = cacheManager.getCache(ORDER_CACHE, String.class, String.class);

        String orderId = String.valueOf(123456789);
        String orderInfo = cache.get(orderId);
        if (StrUtil.isBlank(orderInfo)) {
            orderInfo = getInfo(orderId);
            cache.put(orderId, orderInfo);
        }
        log.info("orderInfo = {}", orderInfo);
    }

    private static String getInfo(String orderId) {
        String info = "";
        // 首先从redis查
        log.info("get data from redis");
        // 不存在 查db
        log.info("get data from mysql");
        info = String.format("{orderId=%s}", orderId);
        return info;
    }
}