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码奴生来只知道前进~ 于 2022-03-27 09:30:00 发布 556 收藏 分类专栏： Java 文章标签： java 版权 Java 专栏收录该内容 64 篇文章0 订阅 订阅专栏 1、添加依赖 <dependency> <groupId>org.apache.poi</groupId> <artifactId>poi</artifactId> <version>4.0.0</version> </dependency> <dependency> <groupId>org.apache.poi</groupId> <artifactId>poi-ooxml</artifactId> <version>4.0.0</version> </dependency> <dependency> <groupId>com.monitorjbl</groupId> <artifactId>xlsx-streamer</artifactId> <version>2.1.0</version> </dependency> 2、导出excel工具类 package com.shucha.deveiface.biz.utils; import com.monitorjbl.xlsx.StreamingReader; import com.sdy.common.model.BizException; import lombok.extern.slf4j.Slf4j; import org.apache.commons.lang3.StringUtils; import org.apache.poi.hssf.usermodel.HSSFWorkbook; import org.apache.poi.ss.usermodel.*; import org.apache.poi.xssf.streaming.SXSSFWorkbook; import org.apache.poi.xssf.usermodel.XSSFRichTextString; import org.apache.poi.xssf.usermodel.XSSFWorkbook; import org.springframework.web.multipart.MultipartFile; import java.io.*; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; @Slf4j public class ExcelUtil { /** * 数据导出成 Excel 数据格式 * * @param headList 表头信息 （为null 或者 size() == 0 证明不存在） * @param dataList 数据信息 * @return 结果数组 */ public static byte[] exportExcel(List<String> headList, List<Map<String, Object>> dataList, String xlsType) throws BizException { byte[] bytes = null; try (Workbook workbook = StringUtils.endsWithIgnoreCase(xlsType, "xlsx") ? new XSSFWorkbook() : new HSSFWorkbook(); ByteArrayOutputStream os = new ByteArrayOutputStream()) { int size = 65530; // int sheetCount = 0; // if (dataList.size() < size) { // // } int sheetCount = dataList == null ? 0 : (dataList.size() < size ? 1 : (dataList.size() % size > 0 ? (dataList.size() / size) + 1 : dataList.size() / size)); for (int i = 0; i < sheetCount; i++) { Sheet sheet = workbook.createSheet("sheet" + i); sheet.setDefaultColumnWidth(13); int rowIndex = 0; if (headList != null && headList.size() > 0) { writerHeader(headList, sheet); rowIndex++; } int end = dataList.size() > (size * (i + 1)) ? size : dataList.size(); writerData(dataList.subList(i * size, end), headList, sheet, rowIndex); } workbook.write(os); bytes = os.toByteArray(); } catch (Exception e) { throw new BizException("" + e); } return bytes; } // 写入本地文件 防止内存溢出 public static void write(List<String> headList, List<Map<String, Object>> dataList, String xlsxPath, Integer size) throws BizException { File file = new File(xlsxPath); // if (file.exists()) { // file.delete(); // } try (SXSSFWorkbook workbook = new SXSSFWorkbook(); FileOutputStream outputStream = new FileOutputStream(file)) { int sheetCount = dataList == null ? 0 : (dataList.size() < size ? 1 : (dataList.size() % size > 0 ? (dataList.size() / size) + 1 : dataList.size() / size)); for (int i = 0; i < sheetCount; i++) { Sheet sheet = workbook.createSheet(i + ""); sheet.setDefaultColumnWidth(13); int rowIndex = 0; if (headList != null && headList.size() > 0) { writerHeader(headList, sheet); rowIndex++; } int end = dataList.size() > (size * (i + 1)) ? size : dataList.size(); writerData(dataList.subList(i * size, end), headList, sheet, rowIndex); } workbook.write(outputStream); } catch (Exception e) { log.error("", e); throw new BizException("" + e); } } //读取本地文件 防止内存溢出 public static List<Map<String, Object>> readExcel(File file, Integer size, Integer current) throws BizException { try (InputStream is = new FileInputStream(file); Workbook workbook = StreamingReader.builder() .rowCacheSize(100) .bufferSize(4096) .open(is)) { List<String> headerList = new ArrayList<>(); List<Map<String, Object>> dataList = new ArrayList<>(); for (Sheet sheet : workbook) { log.info(sheet.getSheetName()); int start = (current * size) + 1; int end = start + 10; int i = 0; for (Row row : sheet) { if (i == 0) { for (Cell cell : row) { headerList.add(cell.getStringCellValue()); } } else if (i > start && i <= end) { Map<String, Object> map = new HashMap<>(); int j = 0; for (Cell cell : row) { map.put(headerList.get(j), cell.getStringCellValue()); j++; } dataList.add(map); } else if (i > end) { break; } i++; } } return dataList; } catch (Exception e) { log.error("", e); throw new BizException("" + e); } } // public static void writeExcel(List<String> headList, List<Map<String, Object>> dataList, String xlsxPath, Integer size) throws BizException { // File file = new File(xlsxPath); // if (file.exists()) { // file.delete(); // } // try (SXSSFWorkbook workbook = new SXSSFWorkbook(); // FileOutputStream outputStream = new FileOutputStream(file)) { // int sheetCount = dataList == null ? 0 : (dataList.size() < size ? 1 : (dataList.size() % size > 0 ? (dataList.size() / size) + 1 : dataList.size() / size)); // for (int i = 0; i < sheetCount; i++) { // Sheet sheet = workbook.createSheet(i + ""); // sheet.setDefaultColumnWidth(13); // int rowIndex = 0; // if (headList != null && headList.size() > 0) { // writerHeader(headList, sheet); // rowIndex++; // } // int end = dataList.size() > (size * (i + 1)) ? size : dataList.size(); // writerData(dataList.subList(i * size, end), headList, sheet, rowIndex); // } // workbook.write(outputStream); // } catch (Exception e) { // throw new BizException("" + e); // } // } // // public static void main(String[] args) throws BizException { List<String> headList = new ArrayList<>(); List<Map<String, Object>> dataList = new ArrayList<>(); headList.add("name"); headList.add("value"); for (int a = 0; a < 70000; a++) { Map<String, Object> map1 = new HashMap<>(); map1.put("name", "测试name" + a); map1.put("value", "测试value" + a); dataList.add(map1); } write(headList, dataList, "/opt/1111.xlsx", 500000); List<Map<String, Object>> maps = readExcel(new File("D:/opt/1111.xlsx"), 10, 50); maps.size(); // Integer a = 0; // for (int i = 0; i < 10; i++) { // ExcelUtil excelUtil = new ExcelUtil(); // excelUtil.test(a); // System.out.println(a); // } // // } // // public void test(Integer a) { // a = a + 1; // } // public static void main(String[] args) throws Exception { // String rootPath = "D:/"; // createImage("检察院看板", new Font("宋体", Font.PLAIN, 30), Paths.get(rootPath, "b" + 4000 + ".png").toFile()); // } // private static int[] getWidthAndHeight(String text, Font font) { // Rectangle2D r = font.getStringBounds(text, new FontRenderContext( // AffineTransform.getScaleInstance(1, 1), false, false)); // int unitHeight = (int) Math.floor(r.getHeight());// // // 获取整个str用了font样式的宽度这里用四舍五入后+1保证宽度绝对能容纳这个字符串作为图片的宽度 // int width = (int) Math.round(r.getWidth()) + 1; // // 把单个字符的高度+3保证高度绝对能容纳字符串作为图片的高度 // int height = unitHeight + 3; // System.out.println("width:" + width + ", height:" + height); // return new int[]{width, height}; return new int[]{190, 28}; // } // // // 根据str,font的样式以及输出文件目录 // public static void createImage(String text, Font font, File outFile) // throws Exception { // // 获取font的样式应用在str上的整个矩形 // int[] arr = getWidthAndHeight(text, font); // int width = arr[0]; // int height = arr[1]; // // 创建图片 // BufferedImage image = new BufferedImage(width, height, // BufferedImage.TYPE_INT_BGR);//创建图片画布 // Graphics g = image.getGraphics(); // g.setColor(Color.WHITE); // 先用白色填充整张图片,也就是背景 // g.fillRect(0, 0, width, height);//画出矩形区域，以便于在矩形区域内写入文字 // g.setColor(Color.black);// 再换成黑色，以便于写入文字 // g.setFont(font);// 设置画笔字体 // g.drawString(text, 0, font.getSize());// 画出一行字符串 // g.drawString(text, 0, 2 * font.getSize());// 画出第二行字符串，注意y轴坐标需要变动 // g.dispose(); // ImageIO.write(image, "png", outFile);// 输出png图片 // } public static byte[] exportExcelHead(List<String> headList, String xlsType) throws BizException { byte[] bytes = null; try (Workbook workbook = StringUtils.endsWithIgnoreCase(xlsType, "xlsx") ? new XSSFWorkbook() : new HSSFWorkbook(); ByteArrayOutputStream os = new ByteArrayOutputStream()) { Sheet sheet = workbook.createSheet(0 + ""); sheet.setDefaultColumnWidth(13); if (headList != null && headList.size() > 0) { writerHeader(headList, sheet); } workbook.write(os); bytes = os.toByteArray(); } catch (Exception e) { throw new BizException("" + e); } return bytes; } /** * 写表头 * * @param headList 表头List * @param sheet sheet */ public static void writerHeader(List<String> headList, Sheet sheet) { Row row = sheet.createRow(0); row.setHeightInPoints(21); RichTextString text; for (int i = 0; i < headList.size(); i++) { Cell cell = row.createCell((short) i); text = new XSSFRichTextString(headList.get(i)); cell.setCellValue(text.toString()); } } /** * 写数据 * * @param dataList 数据 * @param headList 表头 * @param sheet sheel * @param rowIndex 单元格索引 */ public static void writerData(List<Map<String, Object>> dataList, List<String> headList, Sheet sheet, int rowIndex) { Row row; Cell cell; RichTextString text; for (int i = 0; i < dataList.size(); i++) { row = sheet.createRow(rowIndex + i); Map<String, Object> datas = dataList.get(i); for (int j = 0; j < headList.size(); j++) { cell = row.createCell(j); Object value = datas.get(headList.get(j)); String data = value == null ? "" : String.valueOf(value); text = new XSSFRichTextString(data); cell.setCellValue(text); } } } public static Object getValue(Cell cell) { Object cellValue = ""; if (cell != null) { //必须使用switch来获取单元格数据，否则会报错，除非确保execl所有单元格的数据类型一致 switch (cell.getCellType()) { case BOOLEAN://获取布尔型数据 cellValue = cell.getBooleanCellValue(); break; case BLANK://获取空值 cellValue = cell.getBooleanCellValue(); break; case ERROR://获取错误单元格 cellValue = cell.getErrorCellValue(); break; case NUMERIC://获取数字类型的数据 cellValue = cell.getNumericCellValue(); break; case STRING://获取字符串 cellValue = cell.getStringCellValue(); break; } } else { cellValue = ""; } return cellValue; } } 3、测试调用生成excel文件 @GetMapping("/template") @ApiOperation(value = "动态生成excel模板") public void templateDerive(HttpServletResponse response) throws BizException { List<String> paramList = new ArrayList<>(); for (int i=0;i<5;i++) { paramList.add("标题名称"+ i); } try { byte[] bytes = ExcelUtil.exportExcelHead(paramList, "xlsx"); response.setContentType("application/vnd.ms-excel;charset=UTF-8"); response.setCharacterEncoding("utf-8"); String filename = "动态导出模板.xlsx"; response.setHeader("Content-disposition", "attachment;filename=" + URLEncoder.encode(filename, "UTF-8")); response.getOutputStream().write(bytes); } catch (Exception e) { throw new BizException("模板文件生成失败！原因：" + e); } } @GetMapping("/templateExcelData") @ApiOperation(value = "导出模板和数据") public void templateExcelData(HttpServletResponse response) throws BizException { List<String> headList = new ArrayList<>(); // for (int i=0;i<5;i++) { // headList.add("标题名称"+ i); // } // List<String> headList = new ArrayList<>(); List<Map<String, Object>> dataList = new ArrayList<>(); headList.add("name"); headList.add("value"); for (int a = 0; a < 50; a++) { Map<String, Object> map1 = new HashMap<>(); map1.put("name", "测试name" + a); map1.put("value", "测试value" + a); dataList.add(map1); } // List<Map<String, Object>> dataLis = new ArrayList<>(); // for (int j=0;j<5;j++){ // Map<String, Object> map = new HashMap<>(); // map.put("name","数据名称"+j); // dataLis.add(map); // } try { byte[] bytes = ExcelUtil.exportExcel(headList, dataList, "xlsx"); response.setContentType("application/vnd.ms-excel;charset=UTF-8"); response.setCharacterEncoding("utf-8"); String filename = "动态导出模板和数据.xlsx"; response.setHeader("Content-disposition", "attachment;filename=" + URLEncoder.encode(filename, "UTF-8")); response.getOutputStream().write(bytes); } catch (Exception e) { throw new BizException("模板文件生成失败！原因：" + e); } } 版权声明：本文为CSDN博主「码奴生来只知道前进~」的原创文章，遵循CC 4.0 BY-SA版权协议，转载请附上原文出处链接及本声明。 原文链接：https://blog.csdn.net/tanqingfu1/article/details/123705552 |
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