Spring Cache扩展功能实现过程解析

@Bean
public CacheManager cacheManager(
    @SuppressWarnings("rawtypes") RedisTemplate redisTemplate) {
  CustomizedRedisCacheManager cacheManager= new CustomizedRedisCacheManager(redisTemplate);
  cacheManager.setDefaultExpiration(60);
  Map<String,Long> expiresMap=new HashMap<>();
  expiresMap.put("Product",5L);
  cacheManager.setExpires(expiresMap);
  return cacheManager;
}

/**
   * 缓存参数的分隔符
   * 数组元素0=缓存的名称
   * 数组元素1=缓存过期时间TTL
   * 数组元素2=缓存在多少秒开始主动失效来强制刷新
   */
  private String separator = "#";

  /**
   * 缓存主动在失效前强制刷新缓存的时间
   * 单位：秒
   */
  private long preloadSecondTime=0;

@Override
public Cache getCache(String name) {

  String[] cacheParams=name.split(this.getSeparator());
  String cacheName = cacheParams[0];

  if(StringUtils.isBlank(cacheName)){
    return null;
  }

  Long expirationSecondTime = this.computeExpiration(cacheName);

  if(cacheParams.length>1) {
    expirationSecondTime=Long.parseLong(cacheParams[1]);
    this.setDefaultExpiration(expirationSecondTime);
  }
  if(cacheParams.length>2) {
    this.setPreloadSecondTime(Long.parseLong(cacheParams[2]));
  }

  Cache cache = super.getCache(cacheName);
  if(null==cache){
    return cache;
  }
  logger.info("expirationSecondTime:"+expirationSecondTime);
  CustomizedRedisCache redisCache= new CustomizedRedisCache(
      cacheName,
      (this.isUsePrefix() ? this.getCachePrefix().prefix(cacheName) : null),
      this.getRedisOperations(),
      expirationSecondTime,
      preloadSecondTime);
  return redisCache;

}

public ValueWrapper get(Object key) {

  ValueWrapper valueWrapper= super.get(key);
  if(null!=valueWrapper){
    Long ttl= this.redisOperations.getExpire(key);
    if(null!=ttl&& ttl<=this.preloadSecondTime){
      logger.info("key:{} ttl:{} preloadSecondTime:{}",key,ttl,preloadSecondTime);
      ThreadTaskHelper.run(new Runnable() {
        @Override
        public void run() {
          //重新加载数据
          logger.info("refresh key:{}",key);
CustomizedRedisCache.this.getCacheSupport().refreshCacheByKey(CustomizedRedisCache.super.getName(),key.toString());
        }
      });

    }
  }
  return valueWrapper;
}

public interface CacheSupport {

	/**
	 * 刷新容器中所有值
	 * @param cacheName
   */
	void refreshCache(String cacheName);

	/**
	 * 按容器以及指定键更新缓存
	 * @param cacheName
	 * @param cacheKey
   */
	void refreshCacheByKey(String cacheName,String cacheKey);

}

public interface InvocationRegistry {

	void registerInvocation(Object invokedBean, Method invokedMethod, Object[] invocationArguments, Set<String> cacheNames);

}

public final class CachedInvocation {

  private Object key;
  private final Object targetBean;
  private final Method targetMethod;
  private Object[] arguments;

  public CachedInvocation(Object key, Object targetBean, Method targetMethod, Object[] arguments) {
    this.key = key;
    this.targetBean = targetBean;
    this.targetMethod = targetMethod;
    if (arguments != null && arguments.length != 0) {
      this.arguments = Arrays.copyOf(arguments, arguments.length);
    }
  }

}

@Autowired
private CacheManager cacheManager;

@Override
public void refreshCache(String cacheName) {
	this.refreshCacheByKey(cacheName,null);
}

@Override
public void refreshCacheByKey(String cacheName, String cacheKey) {
	if (cacheToInvocationsMap.get(cacheName) != null) {
		for (final CachedInvocation invocation : cacheToInvocationsMap.get(cacheName)) {
			if(!StringUtils.isBlank(cacheKey)&&invocation.getKey().toString().equals(cacheKey)) {
				refreshCache(invocation, cacheName);
			}
		}
	}
}

private Object invoke(CachedInvocation invocation)
			throws ClassNotFoundException, NoSuchMethodException, InvocationTargetException, IllegalAccessException {
	final MethodInvoker invoker = new MethodInvoker();
	invoker.setTargetObject(invocation.getTargetBean());
	invoker.setArguments(invocation.getArguments());
	invoker.setTargetMethod(invocation.getTargetMethod().getName());
	invoker.prepare();
	return invoker.invoke();
}

private void refreshCache(CachedInvocation invocation, String cacheName) {

	boolean invocationSuccess;
	Object computed = null;
	try {
		computed = invoke(invocation);
		invocationSuccess = true;
	} catch (Exception ex) {
		invocationSuccess = false;
	}
	if (invocationSuccess) {
		if (cacheToInvocationsMap.get(cacheName) != null) {
			cacheManager.getCache(cacheName).put(invocation.getKey(), computed);
		}
	}
}

@Override
public void registerInvocation(Object targetBean, Method targetMethod, Object[] arguments, Set<String> annotatedCacheNames) {

	StringBuilder sb = new StringBuilder();
	for (Object obj : arguments) {
		sb.append(obj.toString());
	}

	Object key = sb.toString();

	final CachedInvocation invocation = new CachedInvocation(key, targetBean, targetMethod, arguments);
	for (final String cacheName : annotatedCacheNames) {
		String[] cacheParams=cacheName.split("#");
		String realCacheName = cacheParams[0];
		if(!cacheToInvocationsMap.containsKey(realCacheName)) {
			this.initialize();
		}
		cacheToInvocationsMap.get(realCacheName).add(invocation);
	}
}

@Around("pointcut()")
public Object registerInvocation(ProceedingJoinPoint joinPoint) throws Throwable{

	Method method = this.getSpecificmethod(joinPoint);

	List<Cacheable> annotations=this.getMethodAnnotations(method,Cacheable.class);

	Set<String> cacheSet = new HashSet<String>();
	for (Cacheable cacheables : annotations) {
		cacheSet.addAll(Arrays.asList(cacheables.value()));
	}
	cacheRefreshSupport.registerInvocation(joinPoint.getTarget(), method, joinPoint.getArgs(), cacheSet);
	return joinPoint.proceed();
}

@Cacheable(value = {"Product#5#2"},key ="#id")
public Product getById(Long id) {
  //...
}