第一种 NamedQuery（返回方式为列模式[原生态sql的复杂查询]）
1)dao层处理查询并分页
@SuppressWarnings("unchecked")
public PageResult<T> getList(Integer currentPage){
PageResult<T> pageResult = new PageResult<T>();
int pageSize = Constant.DEFAULT_PAGE_SIZE;
int start = (currentPage - 1) * pageSize;
Query query = getEntityManager().createNamedQuery("ReturnTrainAppyUser");
int total = query.getResultList().size();
// 判断分页
if (start < total && pageSize > 0) {
query.setFirstResult(start);
query.setMaxResults(pageSize);
pageResult.setFirst(start);
pageResult.setPageSize(pageSize);
}
pageResult.setTotalCount(total);
pageResult.setPageResultList(query.getResultList());
return pageResult;
}
2）控制层代码
@RequestMapping("/applyList")
public String applyList(HttpServletRequest request,
HttpServletResponse response, Model model) throws Exception {
Integer currentPage = 1;
Integer pageNum = getIntParameter(request, "pageNum");
if (pageNum != null) {
currentPage = getIntParameter(request, "pageNum");
}
PageResult<TrainApply> a = trainApplyService.findContentResult(currentPage);
addPageResultModel2(a, currentPage, model);
return "common/train/admin/applyList";
}
处理分页参数
protected <E extends VO> void addPageResultModel2(PageResult<E> pct,Integer currentPage, Model model) {
model.addAttribute("totalCount", pct.getTotalCount());
model.addAttribute("numPerPage", Constant.DEFAULT_PAGE_SIZE);
model.addAttribute("pageNum", currentPage);
model.addAttribute("pageNumShown", pct.getPageCount(pct.getTotalCount(), Constant.DEFAULT_PAGE_SIZE));
model.addAttribute("currentPage", currentPage);
model.addAttribute("itemList", pct.getPageResultList());
}
3）实体类
@NamedNativeQueries
(
{
@NamedNativeQuery(
name="ReturnTrainAppyUser",
query=" select a.id as apply_id,b.id as plan_id,b.title as plan_title,(select count(c.id) from train_apply_user c where c.APPLY_ID=a.ID) as 'apply_user_num',a.company as 'apply_company' from train_apply a inner join train_plan b on b.ID=a.PLAN_ID",
resultSetMapping="ReturnTrainAppyUser"),
}
)
@SqlResultSetMappings(
{
@SqlResultSetMapping
(
name="ReturnTrainAppyUser",
entities={},
columns=
{
@ColumnResult(name="apply_id"),
@ColumnResult(name="plan_id"),
@ColumnResult(name="plan_title"),
@ColumnResult(name="apply_user_num"),
@ColumnResult(name="apply_company")
}
)
})
@Entity
@Table(name = "train_apply")
public class TrainApply extends VO {
private static final long serialVersionUID = -6530604520661376764L;
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;// ID
private Long planId;//计划ID
private String orgName;//单位名称
private String roomType;//客房类型
private String roomNumber;//客房数
private String invoiceType;//发票类型
private String status;//状态
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public Long getPlanId() {
return planId;
}
public void setPlanId(Long planId) {
this.planId = planId;
}
public String getOrgName() {
return orgName;
}
public void setOrgName(String orgName) {
this.orgName = orgName;
}
public String getRoomType() {
return roomType;
}
public void setRoomType(String roomType) {
this.roomType = roomType;
}
public String getRoomNumber() {
return roomNumber;
}
public void setRoomNumber(String roomNumber) {
this.roomNumber = roomNumber;
}
public String getInvoiceType() {
return invoiceType;
}
public void setInvoiceType(String invoiceType) {
this.invoiceType = invoiceType;
}
public String getStatus() {
return status;
}
public void setStatus(String status) {
this.status = status;
}
}
4）页面处理
<table width="100%" cellspacing="0" cellpadding="0">
<thead>
<tr class="Train_Resultlist-item">
<th width="50">NO.</th>
<th>培训计划</th>
<th>报名人数</th>
<th>操作</th>
</tr>
</thead>
<tbody>
<c:forEach var="item" items="${itemList}" varStatus="s">
<tr>
<td>${s.index + 1}</td>
<td>${item[2]}</td>
<td>${item[3]}</td>
<td>
<div class="applylist_operate">
<a class="icon icon_train_edit" href="<c:url value='/train/admin/applyEdit/${item[0]}.htm'/>"></a>
<a class="icon icon_train_delete" href="<c:url value='/train/admin/applyDelete'/>/${item[0]}.htm" title="确定要删除吗?删除后数据将不可恢复"></a>
</div>
</td>
</tr>
</c:forEach>
<!-- 分页start -->
<tr>
<td colspan="4">
<div class="green-black">
共${totalCount}条数据.
<a title="首页" href="<c:url value='/train/admin/applyList.htm?pageNum=1'/>">首页</a>
<c:if test="${currentPage le 1}" var="syy">
<a title="上一页" href="#">上一页</a>
</c:if>
<c:if test="${!syy}">
<a title="上一页" href="<c:url value='/train/admin/applyList.htm?pageNum=${currentPage-1}'/>">上一页</a>
</c:if>
<c:forEach var="pageNo" begin="1" end="${pageNumShown}">
<a href="<c:url value='/train/admin/applyList.htm?pageNum=${pageNo}'/>">
<c:if test="${currentPage eq pageNo}" var="rsFy">
<strong>${pageNo}</strong>
</c:if>
<c:if test="${!rsFy}">
${pageNo}
</c:if>
</a>
</c:forEach>
<c:if test="${currentPage ge pageNumShown}" var="xyy">
<a title="下一页" href="#">下一页</a>
</c:if>
<c:if test="${!xyy}">
<a title="下一页" href="<c:url value='/train/admin/applyList.htm?pageNum=${currentPage+1}'/>">下一页</a>
</c:if>
<a title="尾页" href="<c:url value='/train/admin/applyList.htm?pageNum=${pageNumShown}'/>">尾页</a>
</div>
</td>
</tr>
<!-- 分页end -->
</tbody>
</table>
第二种createNativeQuery（返回方式为实体对象集合）
1）dao层代码
@SuppressWarnings("unchecked")
public PageResult<T> getList(Integer currentPage){
int pageSize = Constant.DEFAULT_PAGE_SIZE;
int start = (currentPage - 1) * pageSize;
String sql="select a.* "
+" from train_apply a inner join train_plan b on b.ID=a.PLAN_ID";
PageResult<T> pageResult = new PageResult<T>();
Query query = getEntityManager().createNativeQuery(sql.toString(),TrainApply.class);
int total = query.getResultList().size();
// 判断分页
if (start < total && pageSize > 0) {
query.setFirstResult(start);
query.setMaxResults(pageSize);
pageResult.setFirst(start);
pageResult.setPageSize(pageSize);
}
pageResult.setTotalCount(total);
pageResult.setPageResultList(query.getResultList());
return pageResult;
}
2）其他与第一种类似，实体类不需要注释@NamedNativeQueries等。页面读取为item.planId类似方法获取数据，而不是item[0],item[1]。。。只是对于复杂的sql好像不太适合，比如说要count(id)某一列，目前用这种方式还不能实现几个表直接复杂字段展现查询。待研究。
第三种 注解对象查询（返回方式为实体对象集合）
1）dao层
@Query("select new TrainApplyVo(a.id,count(c.id) as applyUserNum,a.orgName as applyUserCompany)"
+" from TrainApply a,TrainPlan b,TrainApplyUser c where b.id=a.planId and a.id=c.applyId and b.id = ?1 group by b.id")
public List<TrainApply> getTrainApplyListByPlanId(Long planId);
2）这里可查询集合，但是暂时还没有方法如何去处理分页。。。