扩展activiti原表增加新字段
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activiti自带了很多表，如图：
Activiti工作流引擎的数据库表中的表名称都是以 ACT_.第二部分两个字母表示表的类型。使用模糊匹配的方式说明表的类型匹配activiti的服务API.
· ACT_RE_*: RE代表仓储(Repository).这种表前缀以“static”表示流程定义信息或者流程资源信息（如流程的图表和规则等）.
· ACT_RU_*: RU标识为运行(Runtime)时表。包含流程实例，用户任务和变量任务等在运行时的数据信息。这些表只存储Activiti在流程实例运行执行的数据，在流程结束的时候从表中去除数据。从而保持运行时候数据的表的快速和小数据量.
· ACT_ID_*:ID标识为唯一(Identity)的。包含一些唯一的信息如用户，用户做等信息。
· ACT_HI_*:HI表示历史数据(History)表，包括过期的流程实例，过期的变量和过期的任务等。
· ACT_GE_*:GE表示公用(General data)的数据库表类型。
ACT_GE_BYTEARRAY 表保存了开发时候的文件，在工作流部署的时候需要上传相关的工作流文件到相关的项目中。其中如果是文件采用方式如下，将图片和或者文件转换为二进制字节流存储。
bytes_字段保存了文件内容，如果是图片，则是保存了二进制。
由于各个项目的业务特殊性，想扩展ACT_GE_BYTEARRAY 的字段，增加2个新字段SYS_,SWITCHBOARD_字段。
怎么把数据保存到表中，这里采用的是修改源码的办法：
步骤1：修改ACT_GE_BYTEARRAY 表对应实体org.activiti.engine.impl.persistence.entity.ResourceEntity，添加SYS_,SWITCHBOARD_字段：
public class ResourceEntity implements Serializable, PersistentObject {
private static final long serialVersionUID = 1L;
protected String id;
protected String name;
protected byte[] bytes;
protected String deploymentId;
protected boolean generated = false;
//-------------------------------
private String switchboard;
private boolean sys;
...
}
步骤2：修改相应的sql的配置，添加SYS_,SWITCHBOARD_字段。
文件org.activiti.db.mapping.entity.Resource.xml:
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="org.activiti.engine.impl.persistence.entity.ResourceEntity">
<!-- RESOURCE INSERT -->
<insert id="insertResource" parameterType="org.activiti.engine.impl.persistence.entity.ResourceEntity">
insert into ${prefix}ACT_GE_BYTEARRAY(ID_, REV_, NAME_, BYTES_, DEPLOYMENT_ID_, GENERATED_,SWITCHBOARD_,SYS_) values (#{id, jdbcType=VARCHAR}, 1, #{name, jdbcType=VARCHAR}, #{bytes, jdbcType=BLOB}, #{deploymentId, jdbcType=VARCHAR}, #{generated, jdbcType=BOOLEAN}, #{switchboard, jdbcType=VARCHAR},#{sys, jdbcType=BOOLEAN}) </insert>
<!-- RESOURCE UPDATE -->
<!-- RESOURCE DELETE -->
<delete id="deleteResourcesByDeploymentId" parameterType="string">
delete from ${prefix}ACT_GE_BYTEARRAY where DEPLOYMENT_ID_ = #{id}
</delete>
<!-- RESOURCE RESULTMAP -->
<resultMap id="resourceResultMap" type="org.activiti.engine.impl.persistence.entity.ResourceEntity">
<id property="id" column="ID_" jdbcType="VARCHAR" />
<result property="name" column="NAME_" jdbcType="VARCHAR"/>
<result property="bytes" column="BYTES_" jdbcType="BLOB"/>
<result property="generated" column="GENERATED_" jdbcType="BOOLEAN"/>
<result property="switchboard" column="SWITCHBOARD_" jdbcType="VARCHAR"/>
<result property="sys" column="SYS_" jdbcType="BOOLEAN"/>
</resultMap>
<!-- RESOURCE SELECT -->
<select id="selectResourceNamesByDeploymentId" parameterType="org.activiti.engine.impl.db.ListQueryParameterObject" resultType="string">
select NAME_ from ${prefix}ACT_GE_BYTEARRAY where DEPLOYMENT_ID_ = #{parameter} order by NAME_ asc
</select>
<select id="selectResourceByDeploymentIdAndResourceName" parameterType="map" resultMap="resourceResultMap">
select * from ${prefix}ACT_GE_BYTEARRAY
where DEPLOYMENT_ID_ = #{deploymentId}
AND NAME_ = #{resourceName}
</select>
<select id="selectResourcesByDeploymentId" parameterType="org.activiti.engine.impl.db.ListQueryParameterObject" resultMap="resourceResultMap">
select * from ${prefix}ACT_GE_BYTEARRAY where DEPLOYMENT_ID_ = #{parameter} order by NAME_ asc
</select>
<!-- postgresql specific -->
<resultMap id="resourceResultMap_postgres" type="org.activiti.engine.impl.persistence.entity.ResourceEntity">
<id property="id" column="ID_" jdbcType="VARCHAR" />
<result property="name" column="NAME_" jdbcType="VARCHAR"/>
<result property="bytes" column="BYTES_" jdbcType="BINARY"/>
<result property="generated" column="GENERATED_" jdbcType="BOOLEAN"/>
<result property="switchboard" column="SWITCHBOARD_" jdbcType="VARCHAR"/>
<result property="sys" column="SYS_" jdbcType="BOOLEAN"/>
</resultMap>
<!-- postgresql specific -->
<select id="selectResourceByDeploymentIdAndResourceName_postgres" parameterType="map" resultMap="resourceResultMap_postgres">
select * from ${prefix}ACT_GE_BYTEARRAY
where DEPLOYMENT_ID_ = #{deploymentId}
AND NAME_ = #{resourceName}
</select>
<!-- postgresql specific -->
<select id="selectResourcesByDeploymentId_postgres" parameterType="org.activiti.engine.impl.db.ListQueryParameterObject" resultMap="resourceResultMap_postgres">
select * from ${prefix}ACT_GE_BYTEARRAY where DEPLOYMENT_ID_ = #{parameter} order by NAME_ asc
</select>
</mapper>
主要就是修改<insert><resultMap>的内容
步骤3：加载数据文件时候，设置SYS_,SWITCHBOARD_的值
ProcessEngine processEngine = ProcessEngines.getDefaultProcessEngine();
RepositoryService repositoryService = processEngine.getRepositoryService();
DeploymentBuilderImpl deploymentBuilder =(DeploymentBuilderImpl) repositoryService.createDeployment()
.addClasspathResource("activiti/leave.bpmn");
DeploymentEntity deploymentEntity = deploymentBuilder.getDeployment();
ResourceEntity resourceEntity = deploymentEntity.getResource("activiti/leave.bpmn");
resourceEntity.setSwitchboard(getSwitchboard());
resourceEntity.setSys(true);
deploymentEntity.addResource(resourceEntity);
deploymentBuilder.deploy();
注：这里主要是通过ResourceEntity resourceEntity = deploymentEntity.getResource("activiti/leave.bpmn");获得数据库获得对应的实体，然后设置我们新添加的字段的值。
测试结果：
看到上面的数据，SYS_,SWITCHBOARD_字段都有值了，activiti/leave.bpmn是正确的，但是activiti/leave.leave.png对应的值是不正确的。因为这2个添加的值因该是一样的。
下面继续修改：
步骤4：org.activiti.engine.impl.bpmn.deployer.BpmnDeployer,加载activiti/leave.bpmn中的图片
public void deploy(DeploymentEntity deployment) {
...
createResource(resourceName,diagramResourceName, diagramBytes, deployment);
...
}
protected void createResource(String resourceName ,String name, byte[] bytes, DeploymentEntity deploymentEntity) {
ResourceEntity resource = new ResourceEntity();
resource.setName(name);
resource.setBytes(bytes);
resource.setDeploymentId(deploymentEntity.getId());
ResourceEntity resourceEntity = deploymentEntity.getResource(resourceName);
if(resourceEntity!=null){
resource.setSwitchboard(resourceEntity.getSwitchboard());
resource.setSys(resourceEntity.isSys());
}
// Mark the resource as 'generated'
resource.setGenerated(true);
Context
.getCommandContext()
.getDbSqlSession()
.insert(resource);
}
有人要问，问什么要这么修改，没办法，我是一步一步debug，一步一步看源码。
步骤5：文件org.activiti.db.mapping.entity.VariableInstance.xml，添加SYS_,SWITCHBOARD_字段：
<!-- BYTE ARRAY INSERT -->
<insert id="insertByteArray" parameterType="org.activiti.engine.impl.persistence.entity.ByteArrayEntity">
insert into ${prefix}ACT_GE_BYTEARRAY(ID_, REV_, NAME_, BYTES_, DEPLOYMENT_ID_,SWITCHBOARD_,SYS_)
values (
#{id, jdbcType=VARCHAR},
1,
#{name, jdbcType=VARCHAR},
#{bytes, jdbcType=BLOB},
#{deploymentId, jdbcType=VARCHAR},
#{switchboard, jdbcType=VARCHAR},
#{sys, jdbcType=BOOLEAN}
)
</insert>
...
然后测试结果： 