需求

由于生产数据库不能直接连接下载数据，所以需要在监控系统上做一个根据sql动态查询并下载数据的功能。

实现思路

写一个接口，传入需要查询的数据库信息和sql，将查询的接口导出到Excel中

实现细节

入参

@Data
public class ExportDataReq {/*** "jdbc:mysql://localhost:3306/your_database";*/@NotEmptyString url;@NotEmptyString user;@NotEmptyString password;@NotEmptyString sql;@NotEmptyString[] titles;
}

controller

@Slf4j
@Controller
@RequestMapping("/export/")
public class ExportController {@AutowiredExportService exportService;@ApiOperation(value = "下载数据信息", notes = "日期格式：yyyy-MM-dd", httpMethod = "POST")@PostMapping(value = "/exportData")@ResponseBodypublic BaseResponse exportData(@RequestBody @Valid ExportDataReq req,HttpServletResponse response) {BaseResponse baseResponse = exportService.exportData(req, response);return baseResponse;}
}

接口

public interface ExportService {BaseResponse exportData(ExportDataReq req, HttpServletResponse response);
}

服务

@Service
public class ExportServiceImpl implements ExportService {@Overridepublic BaseResponse exportData(ExportDataReq req, HttpServletResponse response) {try (Connection conn = DriverManager.getConnection(req.getUrl(), req.getUser(), req.getPassword());Statement stmt = conn.createStatement();ResultSet rs = stmt.executeQuery(req.getSql())) {//创建wbHSSFWorkbook wb =  new HSSFWorkbook();//创建sheetHSSFSheet sheet = wb.createSheet("data");//添加标题addTitle(sheet,req.getTitles());//添加内容addRow(sheet,rs);//导出writeToResponse(response,wb,"data"+dateNow());return ResponseUtils.success();} catch (Exception ex) {ex.printStackTrace();return ResponseUtils.fail(ex.getMessage());}finally {}}protected void writeToResponse(HttpServletResponse response, HSSFWorkbook wb, String fileName) throws IOException {response.addHeader("Content-Disposition", "attachment;filename="+ URLEncoder.encode(fileName,"utf-8")+".xls");response.setContentType("application/vnd.ms-excel;charset=utf-8");response.setCharacterEncoding("UTF-8");OutputStream out = response.getOutputStream();wb.write(out);out.flush();wb.close();}private void addRow(HSSFSheet sheet, ResultSet rs) throws SQLException {ResultSetMetaData rsMetaData = rs.getMetaData();int columnCount = rsMetaData.getColumnCount();int rowNum = 1;while (rs.next()) {Row row = sheet.createRow(rowNum++);for (int i = 1; i <= columnCount; i++) {Cell cell = row.createCell(i - 1);String columnName = rsMetaData.getColumnName(i);switch (rsMetaData.getColumnType(i)) {case Types.VARCHAR:case Types.CHAR:cell.setCellValue(rs.getString(columnName));break;case Types.INTEGER:cell.setCellValue(rs.getInt(columnName));break;case Types.DOUBLE:cell.setCellValue(rs.getDouble(columnName));break;// Add other types as neededdefault:cell.setCellValue(rs.getString(columnName));}}}}private void addTitle(HSSFSheet sheet, String[] titles) {HSSFRow row = sheet.createRow((int) 0);for (int i=0;i<titles.length;i++) {HSSFCell cell = row.createCell(i);cell.setCellValue(titles[i]);sheet.autoSizeColumn(i);//自动设宽}}private String dateNow(){SimpleDateFormat sdf=new SimpleDateFormat("yyyyMMddhhmmss");return sdf.format(new java.util.Date());}
}

然后通过postman即可导出数据，因为入参类型比较复杂，sql可能较长，所以此处使用post请求。

测试

入参

{"url":"jdbc:mysql://XXXX:63306/gac_order",
"user":"XXX",
"password":"xxx",
"sql":"select order_id,create_time,user_id,status  from order_info limit 1000",
"titles":["order_id","create_time","user_id","status"]}

postman send按钮下拉的Send and Download 可以顺利下载下数据