如何使用SpingBoot 2.7.3和可流动的6.7.2获得流程？

Question

我有一个财务总监：

@RestController
@RequestMapping("processes")
public class ProcessController {
    @Autowired
    private ProcessEngine processEngine;

    @Autowired
    private RepositoryService repositoryService;

    @GetMapping
    public List<ProcessDefinition> listProcess() {
        return processEngine.getRepositoryService().createProcessDefinitionQuery().list();
    }

    @PostMapping(consumes = MediaType.MULTIPART_FORM_DATA_VALUE)
    public Deployment addProcess(@RequestPart MultipartFile file) throws IOException {
        return repositoryService.createDeployment().addInputStream(file.getOriginalFilename(), file.getInputStream()).deploy();
    }
}

我已经上传了test.bpmn20.xml和addProcess()方法，但是当我想要获得带有listProcess方法的ProcessDefinition列表时，控制台警告：

Resolved [org.springframework.http.converter.HttpMessageNotWritableException: Could not write JSON: Cannot invoke "org.flowable.engine.impl.cfg.ProcessEngineConfigurationImpl.getIdentityLinkServiceConfiguration()" because "processEngineConfiguration" is null; nested exception is com.fasterxml.jackson.databind.JsonMappingException: Cannot invoke "org.flowable.engine.impl.cfg.ProcessEngineConfigurationImpl.getIdentityLinkServiceConfiguration()" because "processEngineConfiguration" is null (through reference chain: java.util.ArrayList[0]->org.flowable.engine.impl.persistence.entity.ProcessDefinitionEntityImpl["identityLinks"])]

我的POM.xml：

    <dependency>
      <groupId>org.flowable</groupId>
      <artifactId>flowable-spring-boot-starter</artifactId>
      <version>6.7.2</version>
    </dependency>

为什么控制台警告这个？我能做什么?

请帮帮我，塞克斯！

Answer 1

要从Spring中的REST端点返回变量，需要将变量转换为JSON。但是，可流动API响应没有优化以转换为DTO。这就是为什么您可能无法将它们直接作为响应变量返回。

例如：

@RestController
@RequestMapping("processes")
public class ProcessController {
    @Autowired
    private ProcessEngine processEngine;

    @Autowired
    private RepositoryService repositoryService;

    // ...

    @PostMapping(consumes = MediaType.MULTIPART_FORM_DATA_VALUE)
    public DeploymentDto addProcess(@RequestPart MultipartFile file) throws IOException {
        Deployment deployment = repositoryService.createDeployment()
                .addInputStream(file.getOriginalFilename(), file.getInputStream())
                .deploy();
        return new DeploymentDto(deployment);
    }

    private static class DeploymentDto {
        private final String id;
        private final String name;

        public DeploymentDto(Deployment deployment) {
            this.id = deployment.getId();
            this.name = deployment.getName();
        }

        public String getId() {
            return id;
        }

        public String getName() {
            return name;
        }
    }
}

您可以创建自己的DTO对象，并将可流动API的结果映射到DTO。或者，您可以使用flowable-spring-boot-starter-rest依赖项，它为您提供开箱即用的REST端点。那里的映射会自动为您处理。(有关更多信息，https://www.flowable.com/open-source/docs/bpmn/ch05a-Spring-Boot/#getting-started，请参阅入门指南)