声明：Activiti版本5.22.0。 Activiti在初始化时会生成act_id_*系列与用户、用户组相关的表，但在实际业务中，我们系统可能初期并没有接入工作流，后期接入时就涉及到如何将现有业务表中的用户与Activiti进行对接，本文即简单介绍下思路。

1、自定义实现Activiti用户管理接口

自定义类CustomUserEntityManagerFactory实现SessionFactory接口，重写getSessionType和openSession方法，核心代码如下：

import org.activiti.engine.impl.interceptor.Session;
import org.activiti.engine.impl.interceptor.SessionFactory;
import org.activiti.engine.impl.persistence.entity.UserIdentityManager;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class CustomUserEntityManagerFactory implements SessionFactory{
	@Autowired 
	private CustomUserEntityManager customUserEntityManager;

	@Override
	public Class<?> getSessionType() {
		return UserIdentityManager.class;
	}

	@Override
	public Session openSession() {
		return customUserEntityManager;
	}
	
}

其中，类CustomUserEntityManager继承UserEntityManager类：

import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import org.activiti.engine.identity.Group;
import org.activiti.engine.impl.Page;
import org.activiti.engine.impl.UserQueryImpl;
import org.activiti.engine.impl.persistence.entity.IdentityInfoEntity;
import org.activiti.engine.impl.persistence.entity.UserEntity;
import org.activiti.engine.impl.persistence.entity.UserEntityManager;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Lazy;
import org.springframework.stereotype.Component;
import com.fengunion.scf.data.usermanage.role.service.RoleService;
import com.fengunion.scf.data.usermanage.user.entity.User;
import com.fengunion.scf.data.usermanage.user.service.UserService;
import com.fengunion.scf.data.workflow.common.constant.WorkflowConstants;
import com.fengunion.scf.data.workflow.common.util.ActivitiUserUtil;

@Component
public class CustomUserEntityManager extends UserEntityManager{

	@Autowired
	@Lazy
	private UserService userService;
	@Autowired
	@Lazy
	private RoleService roleService;
	@Override
	public UserEntity findUserById(String userId) {
		User user = getUser(userId);
		return ActivitiUserUtil.toActivitiUser(user);
	}

	@Override
	public List<Group> findGroupsByUser(String userId) {
		if (userId == null) {
            return null;
		}
		User uparam = new User();
		uparam.setPkid(Long.valueOf(userId));
		User user = userService.selectOne(uparam);
		List<String> list = roleService.fingRoleCodeByUserId(Long.valueOf(userId));
		List<Group> gs = ActivitiUserUtil.toActivitiGroups(user.getFkEnterpriseBasicId(),list);
		return gs;
	}

	@Override
	public List<org.activiti.engine.identity.User> findUserByQueryCriteria(UserQueryImpl query, Page page) {
		User user = getUser(query.getId());
		List<org.activiti.engine.identity.User> list = new ArrayList<>();
		list.add(ActivitiUserUtil.toActivitiUser(user));
		return list;
	}
	
	private User getUser(String userId) {
		User user = new User();
		if(WorkflowConstants.INTERFACE_SYSTEM_ID.equals(userId)) {
			user.setPkid(Long.valueOf(WorkflowConstants.INTERFACE_SYSTEM_ID));
			user.setNickName(WorkflowConstants.INTERFACE_SYSTEM_NAME);
			user.setRealName(WorkflowConstants.INTERFACE_SYSTEM_NAME); 
			user.setPswd("");
			user.setEmail("");
		}else {
			User prarmUser = new User();
			prarmUser.setPkid(Long.valueOf(userId));
			user = userService.selectOne(prarmUser);
		}
		return user;
	}

	@Override
	public long findUserCountByQueryCriteria(UserQueryImpl query) {
		throw new RuntimeException("not implement method.");
	}

	@Override
	public IdentityInfoEntity findUserInfoByUserIdAndKey(String userId, String key) {
		throw new RuntimeException("not implement method.");
	}

	@Override
	public List<String> findUserInfoKeysByUserIdAndType(String userId, String type) {
		throw new RuntimeException("not implement method.");
	}

	@Override
	public List<org.activiti.engine.identity.User> findPotentialStarterUsers(String proceDefId) {
		throw new RuntimeException("not implement method.");
	}

	@Override
	public List<org.activiti.engine.identity.User> findUsersByNativeQuery(Map<String, Object> parameterMap,
			int firstResult, int maxResults) {
		throw new RuntimeException("not implement method.");
	}

	@Override
	public long findUserCountByNativeQuery(Map<String, Object> parameterMap) {
		throw new RuntimeException("not implement method.");
	}
	
}

2、自定义实现Activiti用户管理接口

自定义类CustomGroupEntityManagerFactory 实现SessionFactory接口，重写getSessionType和openSession方法，核心代码如下：

import org.activiti.engine.impl.interceptor.Session;
import org.activiti.engine.impl.interceptor.SessionFactory;
import org.activiti.engine.impl.persistence.entity.GroupIdentityManager;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class CustomGroupEntityManagerFactory implements SessionFactory{
	@Autowired
	private CustomGroupEntityManager customGroupEntityManager;	  

	@Override
	public Class<?> getSessionType() {
		return GroupIdentityManager.class;
	}

	@Override
	public Session openSession() {
		return customGroupEntityManager;
	}

}

其中，CustomGroupEntityManager类如下：

import java.util.List;
import java.util.Map;
import org.activiti.engine.identity.Group;
import org.activiti.engine.impl.GroupQueryImpl;
import org.activiti.engine.impl.Page;
import org.activiti.engine.impl.persistence.entity.GroupEntityManager;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Lazy;
import org.springframework.dao.EmptyResultDataAccessException;
import org.springframework.stereotype.Component;
import com.fengunion.scf.data.usermanage.role.service.RoleService;
import com.fengunion.scf.data.usermanage.user.entity.User;
import com.fengunion.scf.data.usermanage.user.service.UserService;
import com.fengunion.scf.data.workflow.common.util.ActivitiUserUtil;

@Component
public class CustomGroupEntityManager extends GroupEntityManager{
	@Lazy
	@Autowired
	private RoleService roleService;
	
	@Lazy
	@Autowired
	private UserService userService;
	
	@Override
	public List<Group> findGroupsByUser(String userId) {
		if (userId == null){  
            return null;
		}
        try {
    		User uparam = new User();
    		uparam.setPkid(Long.valueOf(userId));
    		User user = userService.selectOne(uparam);
    		List<String> list = roleService.fingRoleCodeByUserId(Long.valueOf(userId));
    		List<Group> gs = ActivitiUserUtil.toActivitiGroups(user.getFkEnterpriseBasicId(),list);
            return gs;
        } catch (EmptyResultDataAccessException e) {  
            return null;  
        }
	}

	@Override
	public List<Group> findGroupByQueryCriteria(GroupQueryImpl query, Page page) {
		throw new RuntimeException("not implement method.");
	}

	@Override
	public long findGroupCountByQueryCriteria(GroupQueryImpl query) {
		throw new RuntimeException("not implement method.");
	}

	@Override
	public List<Group> findGroupsByNativeQuery(Map<String, Object> parameterMap, int firstResult, int maxResults) {
		throw new RuntimeException("not implement method.");
	}

	@Override
	public long findGroupCountByNativeQuery(Map<String, Object> parameterMap) {
		throw new RuntimeException("not implement method.");
	}
	
	

}

3、在Activiti配置中注册自己定义的用户、用户组管理类，核心代码如下（我这儿以springboot配置方式为例）：

...
@Autowired
	private CustomUserEntityManagerFactory customUserEntityManagerFactory;
	
	@Autowired
	private CustomGroupEntityManagerFactory customGroupEntityManagerFactory;
...
	@Override
	public void configure(SpringProcessEngineConfiguration processEngineConfiguration) {
...
 		//自定义用户和组
		List<SessionFactory> customSessionFactories = new ArrayList<>();
		customSessionFactories.add(customUserEntityManagerFactory);
		customSessionFactories.add(customGroupEntityManagerFactory);
        processEngineConfiguration.setCustomSessionFactories(customSessionFactories);
...
}

其中ActivitiUserUtil工具类如下：

import java.util.ArrayList;
import java.util.List;
import org.activiti.engine.identity.Group;
import org.activiti.engine.impl.persistence.entity.GroupEntity;
import org.activiti.engine.impl.persistence.entity.UserEntity;
import com.fengunion.scf.data.usermanage.user.entity.User;


public class ActivitiUserUtil {
	public static UserEntity toActivitiUser(User bUser){  
		UserEntity userEntity = new UserEntity();  
        userEntity.setId(bUser.getPkid().toString());  
        userEntity.setFirstName(bUser.getNickName());  
        userEntity.setLastName(bUser.getRealName());  
        userEntity.setPassword(bUser.getPswd());  
        userEntity.setEmail(bUser.getEmail());  
        userEntity.setRevision(1);  
        return userEntity;  
    } 
    
    public static GroupEntity toActivitiGroup(Long enterpriseBasicId,String code){  
        GroupEntity groupEntity = new GroupEntity();  
        groupEntity.setRevision(1);  
        groupEntity.setType("assignment");  
        groupEntity.setId(enterpriseBasicId+"_"+code);  
        return groupEntity;  
    }  
  
    public static List<Group> toActivitiGroups(Long enterpriseBasicId,List<String> roleCodeList){  
        List<Group> groups = new ArrayList<>();  
        for (String code : roleCodeList) {  
            GroupEntity groupEntity = toActivitiGroup(enterpriseBasicId,code);  
            groups.add(groupEntity);  
        }  
        return groups;  
    }  
}

至此，实现自定义用户和用户组就基本实现了。