public ProcessDefinition selectProcessDefinitionByKey(String definitionKey) {
    List<ProcessDefinition> processDefinitions = repositoryService.createProcessDefinitionQuery()
        .processDefinitionKey(definitionKey)
        .orderByProcessDefinitionVersion()
        .desc()
        .list();

    ProcessDefinition processDefinition = null;
    if (processDefinitions.size() > 0) {
        processDefinition = processDefinitions.get(0);
    }
    return processDefinition;
}

@Test
public void testDefinitionQuery(){
    //创建ProcessEngine对象
    ProcessEngine processEngine = ProcessEngines.getDefaultProcessEngine();
    //获取仓库服务
    RepositoryService repositoryService = processEngine.getRepositoryService();
    //获取流程定义集合
    List<ProcessDefinition> processDefinitionList = repositoryService
            .createProcessDefinitionQuery()
            .processDefinitionKey("leaveProcess")
            .list();
    //遍历集合
    for (ProcessDefinition definition:processDefinitionList){
        System.out.println("流程定义ID:"+definition.getId());
        System.out.println("流程定义名称:"+definition.getName());
        System.out.println("流程定义key:"+definition.getKey());
        System.out.println("流程定义版本:"+definition.getVersion());
        System.out.println("流程部署ID:"+definition.getDeploymentId());
        System.out.println("====================");
    }
}