Activiti7将默认缓存替换为Redis

 

文章目录

目录

文章目录

前言

一、描述

二、操作步骤

1.自定义ActivitiDeploymentCache

2.序列化ProcessDefinitionCacheEntry详解

3.存入Redis

4.注入CustomDeploymentCache

总结

---

前言

Activiti7默认将流程缓存到内存里，默认实现为DefaultDeploymentCache，如下

public class DefaultDeploymentCache<T> implements DeploymentCache<T> {

  protected Map<String, T> cache;


  /** Cache with no limit */
  public DefaultDeploymentCache() {
    this.cache = synchronizedMap(new HashMap<String, T>());
  }

  /**
   * Cache which has a hard limit: no more elements will be cached than the limit.
   */
  public DefaultDeploymentCache(final int limit) {
    this.cache = synchronizedMap(new LinkedHashMap<String, T>(limit + 1, 0.75f, true) { // +1 is needed, because the entry is inserted first, before it is removed
          // 0.75 is the default (see javadocs)
          // true will keep the 'access-order', which is needed to have a real LRU cache
          private static final long serialVersionUID = 1L;

          protected boolean removeEldestEntry(Map.Entry<String, T> eldest) {
            boolean removeEldest = size() > limit;
            if (removeEldest && logger.isTraceEnabled()) {
              logger.trace("Cache limit is reached, {} will be evicted", eldest.getKey());
            }
            return removeEldest;
          }

        });
  }
}

可以看到该缓存用HashMap存储在内存中，且无法设置超时等属性，导致内存越来越大，最终溢出，现将缓存替换为Redis。

 

一、描述

本案例采用Activiti7+Jedis，大致流程如下：

1. 自定义ActivitiDeploymentCache类并实现 DeploymentCache类，重写相关方法。
2. 序列化ProcessDefinitionCacheEntry，并保存到redis。
3. 注入ActivitiDeploymentCache。

二、操作步骤

1.自定义ActivitiDeploymentCache

 

@Slf4j
public class ActivitiDeploymentCache implements DeploymentCache<ProcessDefinitionCacheEntry> {

	public static final String DEFAULT_ACTIVITI_DEF_CACHE_BEAN_NAME = "activitiDeploymentCache";

	private static final String PROCESS_DEFINITION_NAME = "processDefinition";

	private static final String BPMN_MODEL_NAME = "BpmnModel";

	@Autowired
	private JedisHelper jedisHelper;

	@Override
	public ProcessDefinitionCacheEntry get(String id) {
		log.info("ActivitiCacheGet --- id:" + id);

		ProcessDefinitionCacheEntry entry = getProcessDefinitionCacheEntry(
				jedisHelper.get(getProcessDefinitionId(id).getBytes()), jedisHelper.get(getBpmnId(id).getBytes()));

		return entry;
	}

	@Override
	public boolean contains(String id) {
		return jedisHelper.hasKey(getProcessDefinitionId(id).getBytes())
				&& jedisHelper.hasKey(getBpmnId(id).getBytes());
	}

	@SneakyThrows
	@Override
	public void add(String id, ProcessDefinitionCacheEntry entry) {
		log.info("ActivitiCacheAdd --- id:" + id);

		/**
		 * // activiti自带Converter，缺失event等属性
		 *
		 * BpmnJsonConverter util = new BpmnJsonConverter(); ObjectNode node =
		 * util.convertToJson(object.getBpmnModel()); CustomBp