Hibernate 中setResultTransformer使用

在使用hibernate框架，查询数据库多张表或者单张表的某几个需要的字段数据时，往往只能通过sql语句配合setResultTransformer将查询到的数据封装到一个map集合中，再将map集合放入list中返回数据。

示例：

控制层：查询还款明细，还款单号、流水号、还款人、还款日期、还款金额//查询还款明细，还款单号、流水号、还款人、还款日期、还款金额

List<Map<String,Object>> list2 = receivableService.findContactwriteoffByBillId(billId);
System.out.println("list2的大小:"+list2);
System.out.println("list2的大小:"+list2.size());
JSONObject jsonTotal2 = new JSONObject();
JSONArray jsonArray2 = new JSONArray();
if(list2.size() != 0){
　　for (int i = 0; i < list2.size(); i++) {

	Object fBillno =list2.get(i).get("fBillno");
	Object banktransactionserialno =list2.get(i).get("banktransactionserialno");
	Object remitoutbankaccountname =list2.get(i).get("remitoutbankaccountname");
	Object operationdatetime =list2.get(i).get("operationdatetime");
	Object amount =list2.get(i).get("amount");				

	JSONObject jsonObject2 = new JSONObject();

	jsonObject2.put("fBillno", fBillno);
	jsonObject2.put("banktransactionserialno", banktransactionserialno);
	jsonObject2.put("remitoutbankaccountname", remitoutbankaccountname);
	jsonObject2.put("operationdatetime", operationdatetime);
	jsonObject2.put("amount", amount);
	jsonArray2.add(jsonObject2);

	jsonTotal2.put("name", "还款明细");
	jsonTotal2.put("options", jsonArray2);				

}　

　service层查询数据

//查询还款明细，还款单号、流水号、还款人、还款日期、还款金额CONTACTWRITEOFF
@Override
public List<Map<String, Object>> findContactwriteoffByBillId(String billId) {
String sql = "SELECT ff.`billno` fBillno,ff.`banktransactionserialno`,ff.`remitoutbankaccountname`,ff.`operationdatetime`,ff.`amount` "
				      +" FROM  fin_contactwriteoff ff WHERE ff.`csbill` ='"+billId+"'";

	Query query = this.getSession().createSQLQuery(sql);

	query.setResultTransformer(new ResultTransformer() {
		private static final long serialVersionUID = 1L;

		public Object transformTuple(Object[] val, String[] arg1) {
			Map<String,Object> m = new HashMap<String,Object>();
			m.put("fBillno", val[0]);
			m.put("banktransactionserialno", val[1]);
			m.put("remitoutbankaccountname",  val[2]);
			m.put("operationdatetime", val[3]);
			m.put("amount", val[4]);
			return m;
		}
		@Override
		public List transformList(List arg0) {
			return arg0;
		}
	});
	List<Map<String,Object>> list = query.list();
	return list;
	}

　　在控制层查询到的数据做个封装返回到前端即可

注：在使用这种方式时有时会遇到报错的问题，原因是类型不对

//查询账单号，账单金额，还款金额，支付方式，账单生成时间
	@Override
	public List<Map<String, Object>> findFinContactsummaryByBillId(String billId) {
		String sql = "SELECT f.billno,c.companyname,c.executive,f.amount,f.writeoffamount,f.journalizedate FROM core_company c,fin_contactsummary f WHERE c.sysid = f.customer and f.sysid='"+billId+"'";
		Query query = this.getSession().createSQLQuery(sql);
		List<Map<String, Object>> llList  = new ArrayList<Map<String, Object>>();
		query.setResultTransformer(new ResultTransformer() {
			private static final long serialVersionUID = 1L;
			public Object transformTuple(Object[] val, String[] aliases) {
				Map<String, Object> map = new HashMap<String, Object>();
				map.put("billno", val[0]);
				map.put("companyname", val[1]);
				map.put("executive", val[2]);
				map.put("amount", val[3]);
				map.put("writeoffamount", val[4]);
				map.put("journalizedate", val[5]);
				llList.add(map);
				return llList;
			}
			@Override
			public List transformList(List collection) {
				return null;
			}
		});
		query.list();
		return llList;

　方式二：

	//查询账单号，账单金额，还款金额，支付方式，账单生成时间
	@Override
	public List<Map<String, Object>> findFinContactsummaryByBillId(String billId) {
		String sql = "SELECT f.billno,c.companyname,c.executive,f.amount,f.writeoffamount,f.journalizedate FROM core_company c,fin_contactsummary f WHERE c.sysid = f.customer and f.sysid='"+billId+"'";
		Query query = this.getSession().createSQLQuery(sql);
		List<Object[]> listm = query.list();
		List<Map<String, Object>> list1 =new ArrayList<Map<String, Object>>();
		Map<String, Object> m = new HashMap<String, Object>();
		for(Object[] s:listm){
			m.put("billno", s[0].toString());
			m.put("companyname", s[1].toString());
			m.put("executive", s[2].toString());
			m.put("amount",s[3].toString());
			m.put("writeoffamount", s[4].toString());
			m.put("journalizedate", s[5].toString());
			list1.add(m);
		}
		return list1;
	}