在spring中利用Guava实现本地Cache的具体配置 第二篇<二>

通过直接实现org.springframework.cache.Cache 接口来管理和实现缓存

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springframework 为我们提供了一套公用的接口模版标准 本文将通过Guava工程 利用单例实现Cache 接口来完成本地缓存的配置

具体代码如下:

public class GuavaCacheUtil implements Cache {    private static Logger log = LoggerFactory.getLogger(GuavaCacheUtil.class);    private static final Object NULL_HOLDER = new NullHolder();    private static final String DEFAULT_NAME = "system_cache";    private final String name;    private final com.google.common.cache.Cache<Object, Object> cache;    private final boolean allowNullValues;    private static GuavaCacheUtil guavaCacheUtil = new GuavaCacheUtil();    public static GuavaCacheUtil builder() {        return guavaCacheUtil;    }    private GuavaCacheUtil() {        this(DEFAULT_NAME, CacheBuilder.newBuilder().maximumSize(100).expireAfterWrite(1, TimeUnit.HOURS).build());    }    private GuavaCacheUtil(String name, com.google.common.cache.Cache<Object, Object> cache) {        this(name, cache, true);    }    private GuavaCacheUtil(String name, com.google.common.cache.Cache<Object, Object> cache, boolean allowNullValues) {        Assert.notNull(name, "Name must not be null");        Assert.notNull(cache, "Cache must not be null");        this.name = name;        this.cache = cache;        this.allowNullValues = allowNullValues;    }    @Override    public String getName() {        return this.name;    }    @Override    public Object getNativeCache() {        return this.cache;    }    @Override    public ValueWrapper get(Object key) {        key = getKey(key.toString());        Object value = this.cache.getIfPresent(key);        log.info("getKey = {}, getObject = {}", key, JsonUtil.objectToJson(value));        return toWrapper(value);    }    @Override    public <T> T get(Object key, Class<T> aClass) {        key = getKey(key.toString());        T value = fromStoreValue(this.cache.getIfPresent(key), aClass);        log.info("getKey = {}, getObject = {}", key, JsonUtil.objectToJson(value));        return value;    }    @Override    public <T> T get(Object o, Callable<T> callable) {        return null;    }    @Override    public void put(Object key, Object value) {        key = getKey(key.toString());        this.cache.put(key, toStoreValue(value));        log.info("getKey = {}, getObject = {}", key, JsonUtil.objectToJson(value));    }    @Override    public ValueWrapper putIfAbsent(Object key, Object value) {        PutIfAbsentCallable callable = new PutIfAbsentCallable(value);        try {            Object result = this.cache.get(key, callable);            return (callable.called ? null : toWrapper(result));        } catch (ExecutionException e) {            throw new IllegalStateException(e);        }    }    @Override    public void evict(Object key) {        this.cache.invalidate(key);        log.info("deleteKey = {}", key);    }    @Override    public void clear() {        this.cache.invalidateAll();        log.info("clearAll");    }    private ValueWrapper toWrapper(Object value) {        return (value != null ? new SimpleValueWrapper(fromStoreValue(value, null)) : null);    }    private static class NullHolder implements Serializable {    }    private Object toStoreValue(Object userValue) {        if (this.allowNullValues && userValue == null) {            return NULL_HOLDER;        }        return userValue;    }    private <T> T fromStoreValue(Object storeValue, Class<T> aClass) {        if (this.allowNullValues && storeValue == NULL_HOLDER) {            return null;        }        if (storeValue != null && aClass != null && !aClass.isInstance(storeValue)) {            throw new IllegalStateException("Cached value is not of required type [" + aClass.getName() + "]: " + storeValue);        }        return (T) storeValue;    }    private class PutIfAbsentCallable implements Callable<Object> {        private final Object value;        private boolean called;        public PutIfAbsentCallable(Object value) {            this.value = value;        }        @Override        public Object call() throws Exception {            this.called = true;            return toStoreValue(this.value);        }    }    private String getKey(String key) {        return name + ":" + key;    }}

测试代码 以及测试结果:

public static String testCachePut(){        Cache cache = GuavaCacheUtil.builder();        cache.put("user_id:1","20");        String user_id = cache.get("user_id:1", String.class);        System.out.println(user_id);        return user_id;    }    public static String testCacheGet(){        Cache cache = GuavaCacheUtil.builder();        cache.put("user_id:2","30");        String user_id = cache.get("user_id:1", String.class);        System.out.println(user_id);        System.out.println(cache.get("user_id:2",String.class));        return user_id;    }    public static void main(String[] args) {        testGuavaCachePut();        testGuavaCacheGet();    }

测试结果 :