activiti 对 mybatis 的使用解析

要点

  • 每个基于 MyBatis 的应用都是以一个 SqlSessionFactory 的实例为核心的
  • activit 的配置核心是 ProcessEngineConfigurationImpl

创建 mybatis SqlSessionFactory

org.activiti.engine.impl.cfg.ProcessEngineConfigurationImpl#initSqlSessionFactory

读取 xml 配置文件

1
2
3
inputStream = getMyBatisXmlConfigurationSteam();
Configuration configuration = initMybatisConfiguration(environment, reader, properties);
sqlSessionFactory = new DefaultSqlSessionFactory(configuration);

用于应用查询的 mapping 文件

文件路径: Activiti\activiti-engine\src\main\resources\org\activiti\db\mapping

activiti 的 createxxxQuery

比如 runtimeService 的 createExecutionQuery,
返回 ExecutionQuery 的 派生类对象 ExecutionQueryImpl 对象

query 实现了 execute 接口,

executeList 方法

List<?> executions = commandContext.getExecutionEntityManager().findExecutionsByQueryCriteria(this, page);

ExecutionEntityManager 负责调用mybatis 的接口

getDbSqlSession().selectList(“selectExecutionsByQueryCriteria”, executionQuery, page);

DbSqlSession 包装了对 mybatis sqlSession 的调用

List loadedObjects = sqlSession.selectList(statement, parameter);

getxxxEntityManager 是 session的子类

xxxEntityManager 将请求转到session, activiti 默认创建了需要的 xxxEntityManager

commandContext.getExecutionEntityManager()

historicTaskInstanceQueryImpl

查询列表,
org.activiti.engine.impl.HistoricTaskInstanceQueryImpl#executeList

if (includeTaskLocalVariables || includeProcessVariables) {
  tasks = commandContext
      .getHistoricTaskInstanceEntityManager()
      .findHistoricTaskInstancesAndVariablesByQueryCriteria(this);
} else {
  tasks = commandContext
      .getHistoricTaskInstanceEntityManager()
      .findHistoricTaskInstancesByQueryCriteria(this);
}

org.activiti.engine.impl.persistence.entity.HistoricTaskInstanceEntityManager#findHistoricTaskInstancesByQueryCriteria

getDbSqlSession().selectList("selectHistoricTaskInstancesByQueryCriteria", historicTaskInstanceQuery);

org.activiti.engine.impl.db.DbSqlSession#selectList(java.lang.String, org.activiti.engine.impl.db.ListQueryParameterObject)

selectListWithRawParameter(statement, parameter, parameter.getFirstResult(), parameter.getMaxResults());
statement = dbSqlSessionFactory.mapStatement(statement);    
List loadedObjects = sqlSession.selectList(statement, parameter);

org.activiti.engine.impl.db.DbSqlSessionFactory#mapStatement

org.apache.ibatis.session.SqlSession#selectList(java.lang.String, java.lang.Object)

activiti 是如何初始化 mybatis 的

观察 :
DbSqlSession,
DbSqlSessionFactory,

自动配置

// 可以配置的 activiti 参数
org.activiti.spring.boot.ActivitiProperties

private List<String> customMybatisMappers;  // 用户自己的 mybatis mapper
private List<String> customMybatisXMLMappers;  // 用户自己的 mybatis xml mapper

org.activiti.spring.boot.AbstractProcessEngineAutoConfiguration#processEngine

org.activiti.spring.boot.AbstractProcessEngineConfiguration#springProcessEngineBean
ProcessEngineFactoryBean processEngineFactoryBean = new ProcessEngineFactoryBean();
processEngineFactoryBean.setProcessEngineConfiguration(configuration);

org.activiti.spring.ProcessEngineFactoryBean#getObject
this.processEngine = processEngineConfiguration.buildProcessEngine();

org.activiti.engine.impl.cfg.ProcessEngineConfigurationImpl#init

org.activiti.engine.impl.cfg.ProcessEngineConfigurationImpl#initDataSource

protected void init() {
    initConfigurators();
    configuratorsBeforeInit();
    initProcessDiagramGenerator();
    initHistoryLevel();
    initExpressionManager();
    initDataSource();
    initVariableTypes();
    initBeans();
    initFormEngines();
    initFormTypes();
    initScriptingEngines();
    initClock();
    initBusinessCalendarManager();
    initCommandContextFactory();
    initTransactionContextFactory();
    initCommandExecutors();
    initServices();
    initIdGenerator();
    initDeployers();
    initJobHandlers();
    initJobExecutor();
    initAsyncExecutor();
    initTransactionFactory();
    initSqlSessionFactory();
    initSessionFactories();
    initJpa();
    initDelegateInterceptor();
    initEventHandlers();
    initFailedJobCommandFactory();
    initEventDispatcher();
    initProcessValidator();
    initDatabaseEventLogging();
    configuratorsAfterInit();
  }

org.activiti.engine.impl.cfg.ProcessEngineConfigurationImpl#initSqlSessionFactory

inputStream = getMyBatisXmlConfigurationSteam();
Environment environment = new Environment("default", transactionFactory, dataSource);
Reader reader = new InputStreamReader(inputStream);

Configuration configuration = initMybatisConfiguration(environment, reader, properties);
sqlSessionFactory = new DefaultSqlSessionFactory(configuration);

org.activiti.engine.impl.cfg.ProcessEngineConfigurationImpl#initSessionFactories

org.activiti.engine.impl.cfg.ProcessEngineConfigurationImpl#initCustomMybatisMappers

org.activiti.engine.impl.cmd.ExecuteCustomSqlCmd#execute
Mapper mapper = commandContext.getDbSqlSession().getSqlSession().getMapper(mapperClass);
return customSqlExecution.execute(mapper);

activiti-springboot使用自定义mybatis-mapper

在application.properties新增自定义配置

spring.activiti.customMybatisXMLMappers=com/codecraft/dao/ProcInstMapper.xml

spring.activiti.customMybatisMappers=com.codecraft.dao.ProcInstMapper

使用方式

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
public List<ProcInstVo> getAllProcInsts(){

	return managementService.executeCustomSql(new AbstractCustomSqlExecution<ProcInstMapper,List<ProcInstVo>>(ProcInstMapper.class) {

		@Override

		public List<ProcInstVo> execute(ProcInstMapper procInstMapper) {

			return procInstMapper.selectAllProcInsts();

		}

	});

}
```	


```java 
ProcessEngineConfiguration cfg = ProcessEngineConfiguration.createProcessEngineConfigurationFromResource("activiti.cfg.xml");
ProcessEngine processEngine = cfg.buildProcessEngine();
ManagementService managementService = processEngine.getManagementService();

// 获取指定表的数据
TablePage tablePage = managementService.createTablePageQuery()
                .tableName(managementService.getTableName(ProcessDefinitionEntity.class))
                .listPage(0,100);
List<Map<String,Object>> rowsList = tablePage.getRows();
for (Map<String,Object> row : rowsList){
     logger.info("row={}",row);
}