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JDBC 之ResultSetMetaData获取列名字

article 2025/7/4 8:11:56

ResultSetMetaData 功能结束：

整个数据库的信息：表名、表的索引、数据库产品的名称和版本、数据库支持的操作(增、删、改、查等等)

获取列名

获取列名字有两种方式

（1）getColumnName(int);

（2）getColumnLabel(int);

这两种方式有什么区别？

项目实例:

String sql = "select tb.sid as sid, tb.arch_sid as archSid, tb.unit_proj_sid as unitProjSid, tb.individual_proj_sid as individualProjSid,\n"+"tb.eng_proj_sid as engProjSid, tb.file_id as fileId, tb.file_no as fileNo, tb.arch_file_no as archFileNo, tb.file_title as fileTitle, \n"+"tb.responsibility as responsibility, tb.file_image_no as fileImageNo, tb.start_date as startDate, tb.end_date as endDate,\n"+"(select s1.value_	from sys_data_dict s1 where s1.key_ = tb.manuscript_code and s1.category_code ='MANUSCRIPT_CODE') as manuscriptCode, \n"+"(select s1.value_	from sys_data_dict s1 where s1.key_ = tb.media_type_code and s1.category_code ='media_type_code') as mediaTypeCode,\n"+"(select s1.value_	from sys_data_dict s1 where s1.key_ = tb.security_level_code and s1.category_code ='SECURITY_LEVEL_CODE') as securityLevelCode,\n"+"(select s1.value_	from sys_data_dict s1 where s1.key_ = tb.storage_type_code and s1.category_code ='STORAGE_TYPE_CODE') as storageTypeCode,\n"+"tb.page_no as pageNo, tb.text_nums as textNums, tb.draw_nums as drawNums, tb.base_nums as baseNums, tb.photo_nums as photoNums,\n"+"tb.negative_nums as negativeNums, tb.open_status as openStatus \n"+"from  ucas_file_info tb where 1 = 1 and (tb.unit_proj_sid is not null or exists(select 1 from ucas_unit_proj proj where proj.sid = tb.unit_proj_sid)) limit %d, %d";

这是一条很简单的查询语句，但是呢，他有很多字段进行了重命名，比如:arch_sid -> archSid、unit_proj_sid -》unitProjSid 等等。

通过ResultSet获取到的ResultSetMetaData对象:

通过第一种方式getColumnName(int)获取到的字段还是为arch_sid \ unit_proj_sid
通过第二种方式getColumnLabel(int)获取到的字段才是为archSid \ unitProjSid

ResultSet rs = null;PreparedStatement ps = null;try{ps = conn.prepareStatement(String.format(sql, pageNo, pageSize), ResultSet.TYPE_FORWARD_ONLY, ResultSet.CONCUR_READ_ONLY);ps.setFetchSize(Integer.MIN_VALUE);rs = ps.executeQuery();ResultSetMetaData colData = rs.getMetaData();ArrayList<HashMap<String, Object>> dataList = new ArrayList<HashMap<String, Object>>();HashMap<String, Object> map = null;String c = null;Object v = null;while (rs.next()) {map = new HashMap<String, Object>(100);for (int i = 1; i <= colData.getColumnCount(); i++) {//c = colData.getColumnName(i);c = colData.getColumnLabel(i);v = rs.getObject(c);if(v instanceof java.sql.Timestamp){// 处理java.sql.Timestamp 与es 日期个数转换if(v != null){DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");String str = dateFormat.format(v);map.put(c, str);}} else {map.put(c, v);}}dataList.add(map);}for (HashMap<String, Object> hashMap2 : dataList) {bulkProcessor.add(new IndexRequest("fileinfo").source(hashMap2));}logger.info("-------------------------- Finally insert number total");// 将数据刷新到es, 注意这一步执行后并不会立即生效，取决于bulkProcessor设置的刷新时间bulkProcessor.flush();}catch(Exception e){e.printStackTrace();logger.error(e.getMessage());}finally {try {rs.close();ps.close();} catch (Exception e) {e.printStackTrace();logger.error(e.getMessage());}}