Mybatis之Select Count(*)的获取返回int的值操作

 public boolean queryByunitclass(String unitclass, String unitsubclass) throws Exception {

  int count = matceMachineUnitMapper.queryByunitclass(unitclass, unitsubclass);
  if (count > 0) {
   return true;
  } else {
   return false;
  }
 }

<select id="queryByunitclass" resultType="java.lang.Integer">
  SELECT COUNT(*) FROM unit
  where unitclass = #{unitclass} and unitsubclass = #{unitsubclass}
 </select>

 /**
  * 查询该分类和子分类是否被使用，使用的个数
  * @param unitclass
  * @param unitsubclass
  * @return
  */
 public int queryByunitclass(@Param("unitclass") String unitclass, @Param("unitsubclass") String unitsubclass);

List<Integer> selectAllTaskidByProjectId(@Param(value = "projectid") int projectid); //传入方案id,返回所有的任务id
 
<select id="selectAllTaskidByProjectId" parameterType="java.lang.Integer" resultType="java.lang.Integer">
   select taskid from tb_project_task where projectid=#{projectid};
</select>