ApachePOI 动态列表生成excel，apachepoiexcel,先创建导出Excel的工

ApachePOI 动态列表生成excel，apachepoiexcel,先创建导出Excel的工

先创建导出Excel的工具类，并带泛型，实体一定要生成属性的get方法，就是普通的Javabean，后面的就是个人发挥了，废话不多说，直接上代码：```javapublic class ExportExcel<T> {

public void exportExcel(Collection<T> dataset, OutputStream out) {      exportExcel("数据导出", null, dataset, out, "yyyy-MM-dd hh:MM:ss");   }   public void exportExcel(String[] headers, Collection<T> dataset,         OutputStream out) {      exportExcel("数据导出", headers, dataset, out, "yyyy-MM-dd hh:MM:ss");   }   public void exportExcel(String[] headers, Collection<T> dataset,         OutputStream out, String pattern) {      exportExcel("数据导出", headers, dataset, out, pattern);   }   public void exportExcel(String title, String[] headers,             Collection<T> dataset, OutputStream out, String pattern) {          // 声明一个工作薄          HSSFWorkbook workbook = new HSSFWorkbook();          // 生成一个表格          HSSFSheet sheet = workbook.createSheet(title);          // 设置表格默认列宽度为30个字节          sheet.setDefaultColumnWidth(30);          // 生成一个样式          HSSFCellStyle style = workbook.createCellStyle();          // 设置这些样式          style.setFillForegroundColor(HSSFColor.WHITE.index);          style.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);          style.setBorderBottom(HSSFCellStyle.BORDER_THIN);          style.setBorderLeft(HSSFCellStyle.BORDER_THIN);          style.setBorderRight(HSSFCellStyle.BORDER_THIN);          style.setBorderTop(HSSFCellStyle.BORDER_THIN);          style.setAlignment(HSSFCellStyle.ALIGN_CENTER);          // 标题字体          HSSFFont font = workbook.createFont();          font.setColor(HSSFColor.BLACK.index);          font.setFontHeightInPoints((short) 12);          font.setBoldweight(HSSFFont.BOLDWEIGHT_BOLD);          // 把字体应用到当前的样式          style.setFont(font);          // 生成并设置另一个样式          HSSFCellStyle style2 = workbook.createCellStyle();          style2.setFillForegroundColor(HSSFColor.WHITE.index);          style2.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);          style2.setBorderBottom(HSSFCellStyle.BORDER_THIN);          style2.setBorderLeft(HSSFCellStyle.BORDER_THIN);          style2.setBorderRight(HSSFCellStyle.BORDER_THIN);          style2.setBorderTop(HSSFCellStyle.BORDER_THIN);          style2.setAlignment(HSSFCellStyle.ALIGN_CENTER);          style2.setVerticalAlignment(HSSFCellStyle.VERTICAL_CENTER);          // 内容字体          HSSFFont font2 = workbook.createFont();          font2.setColor(HSSFColor.BLACK.index);          font2.setBoldweight(HSSFFont.BOLDWEIGHT_NORMAL);          // 把字体应用到当前的样式          style2.setFont(font2);          // 声明一个画图的顶级管理器          HSSFPatriarch patriarch = sheet.createDrawingPatriarch();          // 定义注释的大小和位置,详见文档          HSSFComment comment = patriarch.createComment(new HSSFClientAnchor(0, 0, 0, 0, (short) 4, 2, (short) 6, 5));          // 设置注释内容          comment.setString(new HSSFRichTextString("注释！"));          // 设置注释作者，当鼠标移动到单元格上是可以在状态栏中看到该内容.          comment.setAuthor("yuyidi");          //产生表格标题行          HSSFRow row = sheet.createRow(0);          for (int i = 0; i < headers.length; i++) {             HSSFCell cell = row.createCell(i);             cell.setCellStyle(style);             HSSFRichTextString text = new HSSFRichTextString(headers[i]);             cell.setCellValue(text);          }          //遍历集合数据，产生数据行          Iterator<T> it = dataset.iterator();          int index = 0;          while (it.hasNext()) {             index++;             row = sheet.createRow(index);             T t = (T) it.next();             //利用反射，根据javabean属性的先后顺序，动态调用getXxx()方法得到属性值             Field[] fields = t.getClass().getDeclaredFields();             for (int i = 0; i < fields.length; i++) {                HSSFCell cell = row.createCell(i);                cell.setCellStyle(style2);                Field field = fields[i];                String fieldName = field.getName();                String getMethodName = "get"                       + fieldName.substring(0, 1).toUpperCase()                       + fieldName.substring(1);                try {                    Class tCls = t.getClass();                    Method getMethod = tCls.getMethod(getMethodName,                          new Class[] {});                    Object value = getMethod.invoke(t, new Object[] {});                    //判断值的类型后进行强制类型转换                    String textValue = null;                   if (value instanceof Date) {                       Date date = (Date) value;                       SimpleDateFormat sdf = new SimpleDateFormat(pattern);                        textValue = sdf.format(date);                   }else if (value instanceof Double) {                        textValue = formatter.format(value);                    }  else if (value instanceof byte[]) {                       // 有图片时，设置行高为60px;                       row.setHeightInPoints(60);                       // 设置图片所在列宽度为80px,注意这里单位的一个换算                       sheet.setColumnWidth(i, (short) (35.7 * 80));                       // sheet.autoSizeColumn(i);                       byte[] bsValue = (byte[]) value;                       HSSFClientAnchor anchor = new HSSFClientAnchor(0, 0,                             1023, 255, (short) 6, index, (short) 6, index);                       anchor.setAnchorType(2);                       patriarch.createPicture(anchor, workbook.addPicture(                             bsValue, HSSFWorkbook.PICTURE_TYPE_JPEG));                    } else{                       //其它数据类型都当作字符串简单处理                       textValue = objToString(value);                    }                    //如果不是图片数据，就利用正则表达式判断textValue是否全部由数字组成                    if(textValue!=null){                       Pattern p = Pattern.compile("^//d+(//.//d+)?$");                         Matcher matcher = p.matcher(textValue);                       if(matcher.matches()){                          //是数字当作double处理                          cell.setCellValue(Double.parseDouble(textValue));                       }else{                          HSSFRichTextString richString = new HSSFRichTextString(textValue);                          cell.setCellValue(richString);                       }                    }                } catch (SecurityException e) {                    e.printStackTrace();                } catch (NoSuchMethodException e) {                    e.printStackTrace();                } catch (IllegalArgumentException e) {                    e.printStackTrace();                } catch (IllegalAccessException e) {                    e.printStackTrace();                } catch (InvocationTargetException e) {                    e.printStackTrace();                } finally {                    //清理资源                }             }          }          try {             workbook.write(out);          } catch (IOException e) {             e.printStackTrace();          }   }   private String objToString(Object obj){        return (obj == null) ? "" : obj.toString();   }

}```