使用entityManager做分页查询

场景 jpa遇到查询条件不固定的情况下，使用原生sql查询可以解决这个问题

例子

接口类

    @ApiOperation("PC端,根据条件查询审批分页数据")
    @GetMapping("/pc/getPageApproval")
    public Result> getPageOfApproval(ApprovalPcQueryVo pcQueryVo) {
        Page approvalsWithPc = approvalService.findApprovalsWithPc(pcQueryVo);
        return ResultUtils.success(new ResultPageVo(approvalsWithPc));
    }

vo类

@Data
@ApiModel(description = "Pc,审批回参")
public class ApprovalPagePcVo {
    @ApiModelProperty("审批uuid")
    private String uuid;
	@ApiModelProperty("客户名")
    private String customerName;

    @ApiModelProperty("赔款金额或退款金额")
    private BigDecimal payAmount;

    @ApiModelProperty("服务名称")
    private String serverName;

    @ApiModelProperty("申请类型,0:转会、1:延期、2:赔偿、3:退项、4:退卡、5:余项调整、6:余额调整")
    private Integer type;
    @ApiModelProperty("申请类型名称")
    private String typeName;

    @ApiModelProperty("申请人（顾问）名称")
    private String applyName;

    @ApiModelProperty("顾问所在门店名")
    private String storeName;

    @ApiModelProperty("品牌名")
    private String supplierName;

    @ApiModelProperty("状态,0:待审核、1:已通过、2:已拒绝、3:异常失败、4:系统处理中")
    private Integer state;

    @ApiModelProperty("状态,0:待审核、1:已通过、2:已拒绝、3:异常失败、4:系统处理中")
    private String stateName;

    @ApiModelProperty("申请时间")
    private String date;

    @ApiModelProperty("更新时间")
    private String updateTime;

    public String getTypeName() {
        return ApprovalTypeEnum.getMeassge(type);
    }
    
    public String getStateName() {
        return ApprovalStateEnum.getMessage(state);
    }
}

• service类

   public Page findApprovalsWithPc(ApprovalPcQueryVo pcQueryVo) {
       UuidListDto dto = storeClient.getStoreUuids();
       if (dto == null || dto.getUuids() == null || dto.getUuids().size() == 0) {
           throw new BusinessException("没有门店数据权限");
       }
       UserDTO userDTO = ContextUtil.getCurrentUser();
       pcQueryVo.setSupplierCode(userDTO.getSupplierCode());
       List readVos = approvalDao.getApprovalsPageWithPc(pcQueryVo,dto.getUuids());
       Long total = approvalDao.countGetApproval(pcQueryVo,dto.getUuids());
       Page readVoPage = new PageImpl<>(readVos, PageRequest.of(pcQueryVo.getPage().getCurrentPage(), pcQueryVo.getPage().getPageSize()), total);
       return readVoPage;
   }
  

dao层

• 获取list

  public List getApprovalsPageWithPc(ApprovalPcQueryVo queryVo,List uuids) {
       Query query = entityManager.createNativeQuery(generatorNativeSql(queryVo, false, uuids));
       Map map = generatorParamMap(queryVo);
       map.forEach((k, v) -> {
           query.setParameter(k, v);
       });
       query.setFirstResult(queryVo.getPage().getCurrentPage() * queryVo.getPage().getPageSize());//起始数
       query.setMaxResults(queryVo.getPage().getPageSize());
       query.unwrap(NativeQuery.class).setResultTransformer(Transformers.aliasToBean(ApprovalPagePcVo.class));
       return query.getResultList();
   }
  

• 工厂类

    private String generatorNativeSql(ApprovalPcQueryVo queryVo, boolean isCount,List uuids) {
        StringBuilder sql = new StringBuilder();
        if (isCount) {
            sql.append("select count(1)");
        } else {
            sql.append("select a.uuid," +
                    " a.apply_name  as applyName," +
                    " a.store_name    as storeName," +
                    " a.supplier_name  as supplierName," +
                    " date_format(a.create_time,'%Y-%m-%d %T')  as date," +
                    " date_format(a.update_time,'%Y-%m-%d %T')  as updateTime," +
                    " a.customer_name   as customerName," +
                    " a.pay_amount  as  payAmount," +
                    " a.server_name  as serverName,"+
                    " a.state," +
                    " a.type");
        }
        sql.append(" from t_approval a where 1=1 ");
  
        StringBuilder sp = new StringBuilder(" and a.store_uuid in ( ");
        int i=0;
        for(String s:uuids){
            if(i==0){
                sp.append("'"+s+"'");
            }else{
                sp.append(",'"+s+"'");
            }
            i++;
        }
        sp.append(")");
        sql.append(sp);
  
        if (Objects.nonNull(queryVo)) {
            if (!ObjectUtils.isEmpty(queryVo.getSupplierCode())) {
                sql.append(" and a.approver_uuid = :approverUuid");
            }
            if (Objects.nonNull(queryVo.getType())) {
                sql.append(" and a.type= :type");
            }
            if (!StringUtils.isEmpty(queryVo.getApplyName())) {
                sql.append(" and a.apply_name like :applyName");
            }
            if (Objects.nonNull(queryVo.getState())) {
                sql.append(" and a.state= :state");
            }
            if (!StringUtils.isEmpty(queryVo.getStart())) {
                sql.append(" and date_format(a.create_time,'%Y-%m-%d')>= :start");
            }
            if (!StringUtils.isEmpty(queryVo.getEnd())) {
                sql.append(" and date_format(a.create_time,'%Y-%m-%d')<= :end");
            }
        }
        sql.append(" order by a.create_time desc");
        return sql.toString();
    }
  

工厂类

	 public Page findApprovalsWithPc(ApprovalPcQueryVo pcQueryVo) {
	     UuidListDto dto = storeClient.getStoreUuids();
	     if (dto == null || dto.getUuids() == null || dto.getUuids().size() == 0) {
	         throw new BusinessException("没有门店数据权限");
	     }
	     UserDTO userDTO = ContextUtil.getCurrentUser();
	     pcQueryVo.setSupplierCode(userDTO.getSupplierCode());
	     List readVos = approvalDao.getApprovalsPageWithPc(pcQueryVo,dto.getUuids());
	     Long total = approvalDao.countGetApproval(pcQueryVo,dto.getUuids());
	     Page readVoPage = new PageImpl<>(readVos, PageRequest.of(pcQueryVo.getPage().getCurrentPage(), pcQueryVo.getPage().getPageSize()), total);
	     return readVoPage;
	 }

• 获取总记录数

  public Long countGetApproval(ApprovalPcQueryVo queryVo,List uuids) {
       Query query = entityManager.createNativeQuery(generatorNativeSql(queryVo, true, uuids));
       Map map = generatorParamMap(queryVo);
       map.forEach((k, v) -> {
           query.setParameter(k, v);
       });
       BigInteger total = (BigInteger) query.getSingleResult();
       return total.longValue();
  }