Hibernate中用left join（左外连接）查询映射中没有关联关系的两个表记录问题
一、问题背景
分账表split_summary结构如下：
create table SPLIT_SUMMARY
(
uuid VARCHAR2(32) not null,
star_tdate VARCHAR2(26) default '',
end_date VARCHAR2(26) default '',
store_id VARCHAR2(32) default '',
order_total_price NUMBER(13,2) default 0.00,
product_total_price NUMBER(13,2) default 0.00,
store_fz_price NUMBER(13,2) default 0.00,
shop_fz_price NUMBER(13,2) default 0.00,
status CHAR(1) default '0',
create_date VARCHAR2(26) default '',
note VARCHAR2(512) default ''
)create table STORE
(
store_id VARCHAR2(32) default '' not null,
store_name VARCHAR2(254) default ''
）两表在Hibernate映射中没有关联关系，split_summary中的store_id可能在store表中，也可能不在，要查询所有的split_summary中的记录以及store中store_id和split_summary表中store_id相匹配的记录。很容易想到在oracle使用左连接进行查询，sql语句如下：
select ss.uuid,ss.store_id, s.store_name from split_summary ss left join store s on ss.store_id=s.store_id where 1=1 order by ss.uuid desc二、Hibernate中的左连接查询
Hibernate实战对连接说明如下：
也就是说Hibernate中是不支持on关键字的，如果使用就会报错。Hibernate中的连接条件使用映射关联做的，如下的栗子
Hibernate左连接的栗子
from Item i left join i.bids b with b.amount > 100 where i.description like '%Foo%'三、解决方案
想到了Hibernate的Native SQL查询
native sql的定义
protected Map getQuerySQL(HttpServletRequest request,
ActionForm form) {
OrderSplitForm sform = (OrderSplitForm) form;
// 构建返回Map
Map returnMap = new HashMap();
// 构建参数Map
Map params = new HashMap();
// 编写SQL
StringBuffer sql = new StringBuffer(
"select ss.uuid,ss.store_id,s.store_name,ss.SHOP_FZ_PRICE,ss.STORE_FZ_PRICE," +
"ss.ORDER_TOTAL_PRICE,ss.PRODUCT_TOTAL_PRICE,ss.status,ss.STAR_TDATE,ss.END_DATE," +
"ss.note from split_summary ss left join store s on ss.store_id = s.store_id where 1=1");
// 将账单与店铺关联起来, 使用左连接，解决不是商户的问题
// sql.append(" and ss.storeId = store.id");
// 店铺编号查询条件
if (!StringUtil.isEmpty(sform.getStoreId())) {
sql.append(" and ss.store_Id = :storeId");
params.put("storeId", sform.getStoreId());
}
// 店铺名查询条件
if (!StringUtil.isEmpty(sform.getStoreName())) {
sql.append(" and s.store_Name like :storeName");
params.put("storeName", "%" + sform.getStoreName() + "%");
}
// 开始时间查询条件
if (!StringUtil.isEmpty(sform.getStartDate())) {
sql.append(" and ss.STAR_TDATE >= :startDate");
params.put("startDate", sform.getStartDate());
}
// 结束时间查询条件
if (!StringUtil.isEmpty(sform.getEndDate())) {
sql.append(" and ss.END_DATE <= :endDate");
params.put("endDate", sform.getEndDate());
}
// 分账单状态
if (!StringUtil.isEmpty(sform.getStatus())) {
sql.append(" and ss.status = :status");
params.put("status", sform.getStatus());
}
// 按照创建时间倒序排序
// sql.append(" order by ss.create_Date desc");
sql.append(" order by ss.uuid desc");
returnMap.put("sql", sql.toString());
returnMap.put("param", params);
return returnMap;
}
Hibernate中查询的执行
/**
* Native SQL查询
* @param nativeSQL sql
* @param map 参数绑定map
* @param page 分页查询参数
* @param typeMap 标量查询返回类型
* @return
* @throws Exception
*/
public List listByNativeSQL(String nativeSQL, Map map, Pager page, Map typeMap)
throws Exception {
List list = null;
try {
session = sessionFactory.openSession();
SQLQuery query = session.createSQLQuery(nativeSQL);
if (map != null) {
for (String key : map.keySet()) {
if (nativeSQL.indexOf(":" + key) != -1) {
query.setParameter(key, map.get(key));
System.out.println("param[" + key + "]==="
+ map.get(key));
}
}
}
if (typeMap != null) {
for (String key : typeMap.keySet()) {
query.addScalar(key, typeMap.get(key));
}
}
if (page != null) {
query.setFirstResult(page.getFromRow());
query.setMaxResults(page.getRowsPerPage());
} else {
query.setFirstResult(0);
query.setMaxResults(20);
}
list = query.list();
if (page != null) {
SQLQuery countQuery = session.createSQLQuery(countSql(nativeSQL));
if (map != null) {
for (String key : map.keySet()) {
if (nativeSQL.indexOf(":" + key) != -1) {
countQuery.setParameter(key, map.get(key));
System.out.println("param[" + key + "]==="
+ map.get(key));
}
}
}
if (countQuery != null) {
List countlist = countQuery.list();
if (countlist != null && countlist.size() > 0) {
page.setTotalRow(((Number) countlist.get(0)).intValue());
}
}
}
} catch (Exception e) {
e.printStackTrace();
PubLogs.dbLogError(new StringBuffer("获取查询列表失败!").append(
"PubHibernate.list(nativeSQL)").append(
"nativeSQL=" + nativeSQL), e);
throw e;
} finally {
if (session != null && session.isOpen()) {
session.close();
}
}
if (list != null) {
covertNullToSpace(list);
}
return list;
}
其中包含了返回参数类型的转换addScalar
if (typeMap != null) {
for (String key : typeMap.keySet()) {
query.addScalar(key, typeMap.get(key));
}
}public class SplitSummary extends PubBean {
// 结算账单开始日期
private String startDate = "";
// 结算账单结束日期
private String endDate = "";
// 店铺编号
private String storeId = "";
// 订单总金额
private double orderTotalPrice = 0.00;
// 商品总价
private double productTotalPrice = 0.00;
// 店铺分账金额
private double storeFzPrice = 0.00;
// 平台分账金额
private double shopFzPrice = 0.00;
// 状态
private String status = "";
// 创建时间
private String createDate = "";
// 备注
private String note = "";
/**
* nativeSQL查询时返回字段的类型
* @return
*/
public static Map getTypeMap() {
Map map = new LinkedHashMap();
map.put("uuid", Hibernate.STRING);
map.put("store_id", Hibernate.STRING);
map.put("store_name", Hibernate.STRING);
map.put("SHOP_FZ_PRICE", Hibernate.DOUBLE);
map.put("STORE_FZ_PRICE", Hibernate.DOUBLE);
map.put("ORDER_TOTAL_PRICE", Hibernate.DOUBLE);
map.put("PRODUCT_TOTAL_PRICE", Hibernate.DOUBLE);
map.put("status", Hibernate.STRING);
map.put("STAR_TDATE", Hibernate.STRING);
map.put("END_DATE", Hibernate.STRING);
map.put("note", Hibernate.STRING);
return map;
}
public String getStartDate() {
return startDate;
}
public void setStartDate(String startDate) {
this.startDate = startDate;
}
public String getEndDate() {
return endDate;
}
public void setEndDate(String endDate) {
this.endDate = endDate;
}
public String getStoreId() {
return storeId;
}
public void setStoreId(String storeId) {
this.storeId = storeId;
}
public double getOrderTotalPrice() {
return orderTotalPrice;
}
public void setOrderTotalPrice(double orderTotalPrice) {
this.orderTotalPrice = orderTotalPrice;
}
public double getProductTotalPrice() {
return productTotalPrice;
}
public void setProductTotalPrice(double productTotalPrice) {
this.productTotalPrice = productTotalPrice;
}
public double getStoreFzPrice() {
return storeFzPrice;
}
public void setStoreFzPrice(double storeFzPrice) {
this.storeFzPrice = storeFzPrice;
}
public double getShopFzPrice() {
return shopFzPrice;
}
public void setShopFzPrice(double shopFzPrice) {
this.shopFzPrice = shopFzPrice;
}
public String getStatus() {
return status;
}
public void setStatus(String status) {
this.status = status;
}
public String getCreateDate() {
return createDate;
}
public void setCreateDate(String createDate) {
this.createDate = createDate;
}
public String getNote() {
return note;
}
public void setNote(String note) {
this.note = note;
}
}
四、遇到的坑
1、Hibernate中不支持关键字on，连接条件是通过映射关联进行的，例如：映射文件中配置或者使用注解@OneToMany
2、oracle中表命名别名不能使用as关键字，直接命名即可，例如：split_summary ss
3、addScalar设置返回类型时，要把查询的全部设置，否则设置几个返回几个；还要保证设置参数返回类型的顺序，查询和类型要一致，本例中采用了LinkedHashMap进行设置。