Activiti 自动部署流程资源

左手的ㄟ右手 2022-04-13 10:46 260阅读 0赞

Activiti 整合spring的时候，提供了一个自动部署的特性:

这样当每次启动web容器的时候就会把指定路径的流程资源文件部署到Activiti DB上。不过这样会产生一个问题，资源文件在没经过任何改动的情况下，特别是我们在做Testing的时候，还是会重新部署一个新的版本到DB上，这样会造成不别要的重复部署。我们在部署之前，应该先判断资源文件是否有改动过，如果有，才部署新版本到DB上。  
  
实现这个功能很简单，只需要建立一个实现了 InitializingBean 接口的 spring bean，在afterPropertiesSet()方法里面进行判断和部署就可以了。  
  
具体代码如下:

/** 
     * Automatic resource deployment. 
     *  
     * There is filtering in place that prevents duplicate deployments.Only when the  
     * resources actually have changed, will new deployments be deployed to the Activiti DB. 
     *  
     */  
    public class WorkflowDeployer implements InitializingBean, ApplicationContextAware {  
    
        private static final Logger LOGGER = LoggerFactory.getLogger(WorkflowDeployer.class);  
    
        private Resource[] deploymentResources;  
    
        public void setDeploymentResources(Resource[] resources) {  
            this.deploymentResources = resources;  
        }  
    
        private String category;  
    
        public void setCategory(String category) {  
            this.category = category;  
        }  
    
        ApplicationContext appCtx;  
    
        @Override  
        public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {  
            this.appCtx = applicationContext;  
        }  
    
        @Override  
        public void afterPropertiesSet() throws Exception {  
            if (category == null){  
                throw new FatalBeanException("Missing property: category");  
            }  
            if (deploymentResources != null) {  
                RepositoryService repositoryService = appCtx.getBean(RepositoryService.class);  
                for (Resource r : deploymentResources) {  
                    String deploymentName = category + "_" + r.getFilename();  
                    String resourceName = r.getFilename();  
                    boolean doDeploy = true;  
                    List<Deployment> deployments = repositoryService.createDeploymentQuery().deploymentName(deploymentName).orderByDeploymenTime().desc().list();  
                    if (!deployments.isEmpty()) {  
                        Deployment existing = deployments.get(0);  
                        try {  
                            InputStream in = repositoryService.getResourceAsStream(existing.getId(), resourceName);  
                            if (in != null) {  
                                File f = File.createTempFile("deployment","xml", new File(System.getProperty("java.io.tmpdir")));  
                                f.deleteOnExit();  
                                OutputStream out=new FileOutputStream(f);  
                                IOUtils.copy(in,out);  
                                in.close();  
                                out.close();  
                                doDeploy =  (FileUtils.checksumCRC32(f) != FileUtils.checksumCRC32(r.getFile()));  
                            }  
                            else  
                                throw new ActivitiException("Unable to read resource " + resourceName + ", input stream is null");  
                        } catch (ActivitiException ex) {  
                            //do nothing, simply re-deploy  
                            LOGGER.error("Unable to read " + resourceName + " of deployment " + existing.getName() + ", id: " + existing.getId() + ", will re-deploy");  
                        }  
                    }  
                    if (doDeploy) {  
                        repositoryService.createDeployment()  
                                .name(deploymentName)  
                                .addInputStream(resourceName, r.getInputStream())  
                                .deploy();  
                        LOGGER.warn("Deployed BPMN20 resource " + r.getFilename());  
                    }  
                }  
            }  
        }  
    
    }

然后在spring的配置文件里面配置好这个bean就可以了.