Question

我正在使用spring jdbc模板项目。在那里，我想从一个到多个关系加载所有记录。以下是我的数据库结构

class ReceiptHeader{
 int rcptid,
 String rcptname;
 List<ReceiptDetails> receiptDetails;
}

class ReceiptDetails{
 int detid;
 String comment;
}

我想将ReceiptHeader中的所有记录加载到列表＆lt;＆gt;并且所有的ReceiptDetails记录都必须附在它上面。

我的代码是，

@Override   
    public <E, U, V> List<E> getData(U param, V invId) throws Exception {
        List<ReceiptHdr> result = null;

        try {
            logger.info("--------Excute getData -->");
            JdbcTemplate jdbcTemplate = new JdbcTemplate(this.dataSource);

            final Map<Integer, ReceiptHdr> rcptHdr = new HashMap<Integer, ReceiptHdr>();

            jdbcTemplate.query("select h.rcpt_id, h.remark, d.det_id, d.comment from receipt_hdr h inner join receipt_det on h.rcpt_id = d.rcpt_id", new RowMapper<ReceiptDet>() {
                public ReceiptHdr mapRow(ResultSet rs, int rowNum) throws SQLException {
                    Integer rcptId = rs.getInt("rcpt_id");
                    ReceiptHdr rcptHeader = (ReceiptHdr) rcptHdr.get(rcptId);
                    if (rcptHeader == null) {
                        String hdrRemark = rs.getString("remark");
                        rcptHeader = new ReceiptHdr();
                        rcptHeader.setRcptId(rcptId);
                        rcptHeader.setHdrRemark(hdrRemark);
                        rcptHdr.put(rcptId, rcptHeader);
                    }
                    ReceiptDet rcptDet = new ReceiptDet();
                    rcptDet.setRcptDetId(rs.getInt("det_id"));
                    rcptDet.setDeleteComment(rs.getString("comment"));
                    rcptHeader.getReceiptDets().add(rcptDet);
                    return rcptDet;
                }
            });
            result = new ArrayList<ReceiptHdr>(rcptHdr.values());

            logger.info("--------Excute ReceiptHdr -->" + rcptHdr);

        } catch (Exception e) {
            logger.error("Error : Get Data-->" + e);
        }
        return (List<E>) result;
    }

documentation

我试过以下两种方法，但不成功， The screen shot of the code is here

Answer 1

使用JdbcTemplate重载的query方法与ResultSetExtractor。

public <T> T query(String sql,
                   ResultSetExtractor<T> rse)
            throws DataAccessException

永远不会访问和修改匿名类中的数据。这不是好习惯。

       final Map<Integer, ReceiptHdr> rcptHdr = jdbcTemplate.query("select h.rcpt_id, h.remark, d.det_id, d.comment from receipt_hdr h inner join receipt_det on h.rcpt_id = d.rcpt_id", new ResultSetExtractor<Map<Integer, ReceiptHdr>>() {
            public Map<Integer, ReceiptHdr> extractData(ResultSet rs) throws SQLException, DataAccessException {
                Map<Integer, ReceiptHdr> rcptHdr = new HashMap<Integer, ReceiptHdr>();
                while(rs.next()) {
                    Integer rcptId = rs.getInt("rcpt_id");
                    ReceiptHdr rcptHeader = (ReceiptHdr) rcptHdr.get(rcptId);
                    if (rcptHeader == null) {
                        String hdrRemark = rs.getString("remark");
                        rcptHeader = new ReceiptHdr();
                        rcptHeader.setRcptId(rcptId);
                        rcptHeader.setHdrRemark(hdrRemark);
                        rcptHdr.put(rcptId, rcptHeader);
                    }
                    ReceiptDet rcptDet = new ReceiptDet();
                    rcptDet.setRcptDetId(rs.getInt("det_id"));
                    rcptDet.setDeleteComment(rs.getString("comment"));
                    rcptHeader.getReceiptDets().add(rcptDet);
                }
                return rcptHdr;
            }
        });

Answer 2

最后我找到了解决方案，我错过了一些语法错误。

任何方式使用匿名类来获取数据并不是一个好习惯。

{{1}}

Spring Jdbctemplate一对多数据检索

2 个答案: