最近在写一个导出excel时，采用了模板方法进行编写。
导出excel模板抽象类
import com.dream.biz.service.utils.DateFormatUtil; import org.apache.poi.hssf.usermodel.*; import org.apache.poi.ss.usermodel.BorderStyle; import org.apache.poi.ss.usermodel.HorizontalAlignment; import org.apache.poi.ss.usermodel.VerticalAlignment; import javax.servlet.http.HttpServletResponse; import java.io.OutputStream; import java.util.ArrayList; import java.util.List; /** * @Description:导出excel，模板方法抽象类 * @Author: liyunqiang * @Date: Created in 15:14 2018/5/4 */ public abstract class ExportExcel<T> { protected String tableName;// 表名 protected List<String> headList;// 表头数组 protected List<List<Object>> datasList;// 内容集合 protected List<Integer> widthList;// 宽度设置数组 /** * 导出excel * @param response web的response相应 * @param list 对象数组 */ public void exportExcel(HttpServletResponse response, List<T> list) { // 1、数据初始化 this.init(); // 2、设置表名 this.setTableName(); // 3、设置表头 this.setHeadList(); // 4、设置内容 this.setDatasList(list); // 5、设置宽度 this.setWidthList(); // 6、导出 this.exportExcel(response); } /** * 数据初始化 */ private void init() { tableName = "数据"; headList = new ArrayList<String>();// 表头数组 datasList = new ArrayList<List<Object>>();// 内容集合 widthList = new ArrayList<Integer>();// 宽度设置数组 } /** * 设置表名 */ protected abstract void setTableName(); /** * 设置表头数组 */ protected abstract void setHeadList(); /** * 设置内容数组 */ protected abstract void setDatasList(List<T> list); /** * 设置表格宽度 * 钩子方法，如需修改，在子类重写方法 */ protected void setWidthList() { for (int i = 0; i < headList.size(); i++) { widthList.add(4000); } } /** * 生成excel文件 */ private void exportExcel(HttpServletResponse response) { // 创建一个新的Excel HSSFWorkbook workBook = new HSSFWorkbook(); // 创建sheet页 HSSFSheet sheet = workBook.createSheet(); // 冻结第一列、第一行 sheet.createFreezePane(1, 1); // sheet页名称 workBook.setSheetName(0, tableName); // 创建header页 HSSFHeader header = sheet.getHeader(); // 设置标题居中 header.setCenter(tableName); // 标题字体样式 HSSFFont columnHeadFont = workBook.createFont(); columnHeadFont.setFontName("宋体"); columnHeadFont.setFontHeightInPoints((short) 10); columnHeadFont.setBold(true); // 列头的样式 HSSFCellStyle columnHeadStyle = workBook.createCellStyle(); columnHeadStyle.setFont(columnHeadFont); columnHeadStyle.setAlignment(HorizontalAlignment.CENTER); columnHeadStyle.setVerticalAlignment(VerticalAlignment.CENTER); columnHeadStyle.setWrapText(true); columnHeadStyle.setBorderTop(BorderStyle.THIN); columnHeadStyle.setBorderBottom(BorderStyle.THIN); columnHeadStyle.setBorderLeft(BorderStyle.THIN); columnHeadStyle.setBorderRight(BorderStyle.THIN); // 普通单元格样式 HSSFCellStyle style = workBook.createCellStyle(); style.setVerticalAlignment(VerticalAlignment.CENTER); style.setWrapText(true);// 自动换行 style.setBorderTop(BorderStyle.THIN); style.setBorderBottom(BorderStyle.THIN); style.setBorderLeft(BorderStyle.THIN); style.setBorderRight(BorderStyle.THIN); // 设置第一行为Header HSSFRow row = sheet.createRow(0); // 添加表格 List<HSSFCell> cellList = new ArrayList<HSSFCell>(); HSSFCell cell; for (int i = 0; i < headList.size(); i++) { cell = row.createCell(i); cell.setCellValue(headList.get(i)); cell.setCellStyle(columnHeadStyle);// 样式 cellList.add(cell); } Object object = null; List<Object> datas; int len; if (datasList != null && !datasList.isEmpty()) { for (int i = 0; i < datasList.size(); i++) { datas = datasList.get(i); len = datas.size(); row = sheet.createRow(i + 1); // 具体数据 for (int j = 0; j < headList.size(); j++) { cell = row.createCell(j); cell.setCellStyle(style);// 样式 if (len > j) {// 确保不会数组越界 object = datas.get(j); if (object != null) { cell.setCellValue(object.toString()); } } cellList.add(cell); } } } // 设置表格宽度 for (int i = 0; i < widthList.size(); i++) { sheet.setColumnWidth(i, widthList.get(i)); } // 通过Response把数据以Excel格式保存 response.reset(); response.setContentType("application/msexcel;charset=UTF-8"); try { response.addHeader("Content-Disposition", "attachment;filename=\"" + new String((DateFormatUtil.getStringDate() + tableName + ".xls").getBytes("UTF-8"), "ISO8859_1") + "\""); OutputStream out = response.getOutputStream(); workBook.write(out); out.flush(); out.close(); } catch (Exception e) { e.printStackTrace(); } } } import com
