Jpa框架下拼接原生sql 并执行

利用jpa的entityManager 执行sql 并执行
其中：
EntityManager.createNativeQuery(SQL)返回的是Object对象
entityManager.createNativeQuery(SQL,WebInfo.class)返回的是映射后的实例对象

Query.getSingleResult() 执行SQL语句，返回一个查询结果，常用的还有以下方法
Query.getResultList() () 执行SQL语句，返回一个List集合
Query.getFirstResult() () 执行SQL语句，返回一个系列结果集合的第一个

直接上例子：

1. EntityManager.createNativeQuery(SQL)返回的是Object对象
   entityManager.createNativeQuery(SQL,WebInfo.class)返回的是映射后的实例对象

  public List<User> getByCompanyFinanceRoleManager(Long companyID , String authorityName){         StringBuffer querySql = new StringBuffer("select a.* from art_user a , art_user_authority b where a.id = b.user_id and a.company_id = :companyId " +                 " and b.authority_name =  :authorityName");         Query query = entityManager.createNativeQuery(querySql.toString() , User.class);         query.setParameter("companyId" , companyID);         query.setParameter("authorityName" , authorityName);         List<User> list = query.getResultList();         return list;     }

2. Query.getSingleResult() 执行SQL语句，返回一个查询结果

  public Long getByFinanceRoleApplicationCount(ApplicationSearchParamDTO param){         StringBuffer queryCount = new StringBuffer("select count(er.id) from atl_application er , atl_loan_application b where er.application_oid = b.application_oid and er.status not in (1010 ,1011)");         getSql(queryCount , param);         Query count = entityManager.createNativeQuery(queryCount.toString() );         setQueryParam(count , param);         Object obj = count.getSingleResult();         Long countNum = ((BigInteger) obj).longValue();         return countNum;     }  public void getSql(StringBuffer querySql , ApplicationSearchParamDTO param ){         //公司oid         if (!StringUtils.isEmpty(param.getCompanyOID())) {             querySql.append(" and er.company_oid = :companyOID ");         }         //申请人oid         if (CollectionUtils.isNotEmpty(param.getApplicantOIDs())){             querySql.append(" and er.applicant_oid in ( :applicantOID ) ");         }         if (!StringUtils.isEmpty(param.getBusinessCode())){             querySql.append(" and b.business_code like CONCAT('%' , :businessCode , '%') ");         }         if (CollectionUtils.isNotEmpty(param.getDepartmentOIDs()) && CollectionUtils.isNotEmpty(param.getFinanceRoleCorporationOids()) && CollectionUtils.isEmpty(param.getCorporationOIDs())) {             querySql.append(" and ( b.department_oid in ( :departmentOID ) or er.corporation_oid in ( :corporationOID ) OR b.department_oid is null OR er.corporation_oid is null )");         }else if(CollectionUtils.isNotEmpty(param.getDepartmentOIDs()) && CollectionUtils.isEmpty(param.getCorporationOIDs())){             querySql.append(" and ( b.department_oid in ( :departmentOID ) OR b.department_oid is null ) ");         }else if(CollectionUtils.isNotEmpty(param.getFinanceRoleCorporationOids()) && CollectionUtils.isEmpty(param.getCorporationOIDs())){             querySql.append(" and ( er.corporation_oid in ( :corporationOID ) OR er.corporation_oid is null ) ");         }         if (CollectionUtils.isNotEmpty(param.getCorporationOIDs())){             querySql.append(" and er.corporation_oid in ( :corporationOID ) ");         }         //开始时间         if (param.getStartDate() != null) {             querySql.append(" and er.last_modified_date >= :startDate ");         }         //结束时间         if (param.getEndDate() != null) {             querySql.append(" and er.last_modified_date <= :endDate ");         }         //单据类型         if (CollectionUtils.isNotEmpty(param.getType())) {             querySql.append(" and er.type in ( :type ) ");         }         //单据状态         if (CollectionUtils.isNotEmpty(param.getStatus())) {             querySql.append(" and er.status in ( :status )");         }        /* //申请单oid         if (CollectionUtils.isNotEmpty(param.getApplicationOIDs())) {             querySql.append(" and er.application_oid in ( :applicationOID )");         }*/          //反选         if(CollectionUtils.isNotEmpty(param.getExcludedApplicationOIDs())){             querySql.append(" and er.application_oid not in ( :excludedApplicationOID )");         }     }

3. Query.getResultList()

    public List<DepartmentDTO> getDepartmentsOfReportLine(UUID reportLineOID) {         String sql = "SELECT d.department_oid, d.`name` FROM art_department d INNER JOIN art_report_obj ro on ro.obj_oid = d.department_oid AND ro.obj_type = '2' "             + "and ro.report_line_oid = '" + reportLineOID + "'";         Query query = entityManager.createNativeQuery(sql);         List<DepartmentDTO> list = new ArrayList<>();         List<Object[]> rtList = query.getResultList();         for (Object[] objects : rtList) {             DepartmentDTO departmentDTO = new DepartmentDTO();             departmentDTO.setDepartmentOID(UUID.fromString(objects[0].toString()));             departmentDTO.setName(objects[1].toString());             list.add(departmentDTO);         }         return list;     }     ```  直接参考例子，拼接正确sql 即可。   如果觉得本篇文章帮到你的话， 请关注我新建的公众号： **程序员BenJi ** 定期分享优质的知识思维导图，帮助大家建立结构化的知识体系，欢迎关注~