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Java Poi Excel 大量数据导入导出

Java Poi Excel 大量数据导入导出

作者: 沉思的老猫 | 来源:发表于2017-12-09 15:58 被阅读0次

    1、Excel导入
    1)读取文件
    2)转换Workbook
    3)拼装数据集

        String filePath = "excle/20171207.xls";
        String fullPath = Thread.currentThread().getContextClassLoader().getResource(filePath).getPath();
        Workbook wb = null;
        try {
            InputStream in = new BufferedInputStream(new FileInputStream(fullPath));
            wb = WorkbookFactory.create(in); 
        } catch (FileNotFoundException e) {
            e.printStackTrace();
            throw new RuntimeException(e);
        } catch (InvalidFormatException e) {
            e.printStackTrace();
            throw new RuntimeException(e);
        } catch (IOException e) {
            e.printStackTrace();
            throw new RuntimeException(e);
        }
        List<String[]> list = new ArrayList<String[]>();
        for (int sheetIndex = 0; sheetIndex < wb.getNumberOfSheets(); sheetIndex++){
            Sheet st = wb.getSheetAt(sheetIndex);
            // 第一行为标题,不取
            for (int rowIndex = 0; rowIndex <= st.getPhysicalNumberOfRows(); rowIndex++){
                Row row = st.getRow(rowIndex);
                if (row == null) {
                    continue;
                }
                String[] cells = cellArray(row);
                list.add(cells);
            }
        }
    

    2、Excel导出
    1)声明一个工作薄
    2)设置样式
    3)设置字体
    4)设置表格标题行
    5)生成表格具体数据行,超过上限生成下一个sheet
    6)利用反射获取对应的属性值并赋值到表格
    7)判断值的类型后进行格式转换(日期,浮点数特殊格式处理)

    private static Pattern NUMBER_PATTERN = Pattern.compile("^//d+(//.//d+)?$");
    public <T> byte[] exportExcel(String title, String[] headers, Collection<T> dataSet, String pattern) {
            // 声明一个工作薄
            SXSSFWorkbook workbook = new SXSSFWorkbook(10000);
            // 生成一个表格
            // 生成一个样式
            CellStyle style = workbook.createCellStyle();
            // 设置这些样式
            style.setFillForegroundColor(HSSFColor.SKY_BLUE.index);
            style.setFillPattern(FillPatternType.SOLID_FOREGROUND);
            style.setBorderBottom(BorderStyle.THIN);
            style.setBorderLeft(BorderStyle.THIN);
            style.setBorderRight(BorderStyle.THIN);
            style.setBorderTop(BorderStyle.THIN);
            style.setAlignment(HorizontalAlignment.CENTER);
            // 生成一个字体
            Font font = workbook.createFont();
            font.setColor(HSSFColor.VIOLET.index);
            font.setFontHeightInPoints((short) 12);
            font.setBold(true);
            // 把字体应用到当前的样式
            style.setFont(font);
    
            Font font2 = workbook.createFont();
            Sheet sheet = null;
            Row row = null;
            int index = 0;
            int sheetnum = 0;
            Iterator<T> it = dataSet.iterator();
            // 生成表格标题行
            sheet = workbook.createSheet(title + sheetnum);
            sheet.setDefaultColumnWidth(15);
            row = sheet.createRow(0);
            for (int i = 0; i < headers.length; i++) {
                Cell cell = row.createCell(i);
                cell.setCellStyle(style);
                XSSFRichTextString text = new XSSFRichTextString(headers[i]);
                cell.setCellValue(text);
            }
            ByteArrayOutputStream baos = null;
            try {
                // 生成表格具体数据行
                while (it.hasNext()) {
                    index++;
                    // 如果数据大于5000行,生成下一个sheet
                    if (index > 50000) {
                        index = 0;
                        ++sheetnum;
                        sheet = workbook.createSheet(title + sheetnum);
                        sheet.setDefaultColumnWidth(15);
                        row = sheet.createRow(0);
                        for (int i = 0; i < headers.length; i++) {
                            Cell cell = row.createCell(i);
                            cell.setCellStyle(style);
                            XSSFRichTextString text = new XSSFRichTextString(headers[i]);
                            cell.setCellValue(text);
                        }
                    }
                    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++) {
                        Cell cell = row.createCell(i);
                        cell.setCellStyle(style);
                        Field field = fields[i];
                        String fieldName = field.getName();
    
                        Object value = PropertyUtils.getProperty(t, fieldName);
                        // 判断值的类型后进行强制类型转换
                        String textValue = null;
                        if (value instanceof Integer) {
                            int intValue = (Integer) value;
                            cell.setCellValue(intValue);
                        } else if (value instanceof Float) {
                            float fValue = (Float) value;
                            textValue = new XSSFRichTextString(
                                    String.valueOf(fValue)).toString();
                            cell.setCellValue(textValue);
                        } else if (value instanceof Double) {
                            double dValue = (Double) value;
                            textValue = new XSSFRichTextString(
                                    String.valueOf(dValue)).toString();
                            cell.setCellValue(textValue);
                        } else if (value instanceof Long) {
                            long longValue = (Long) value;
                            cell.setCellValue(longValue);
                        }
                        if (value instanceof Boolean) {
                            boolean bValue = (Boolean) value;
                            textValue = "true";
                            if (!bValue) {
                                textValue = "false";
                            }
                        } else if (value instanceof Date) {
                            Date date = (Date) value;
                            if ("".equals(pattern)) {
                                pattern = "yyy-MM-dd";
                            }
                            SimpleDateFormat sdf = new SimpleDateFormat(pattern);
                            textValue = sdf.format(date);
                        } else {
                            if (null == value || "".equals(value)) {
                                value = "";
                            } else {
                                textValue = value.toString();
                            }
                        }
                        // 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 = NUMBER_PATTERN;
                            Matcher matcher = p.matcher(textValue);
                            if (matcher.matches()) {
                                // 是数字当作double处理
                                cell.setCellValue(Double.parseDouble(textValue));
                            } else {
                                XSSFRichTextString richString = new XSSFRichTextString(
                                        textValue);
                                font2.setColor(HSSFColor.BLUE.index);
                                richString.applyFont(font2);
                                cell.setCellValue(richString);
                            }
                        }
                    
                    }
                }
                baos = new ByteArrayOutputStream();
                workbook.write(baos);
            } catch (Exception e) {
                e.printStackTrace();
                throw new RuntimeException("poi处理出错");
            } finally{
                try {
                    workbook.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return baos.toByteArray();
        }
    

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