接上一篇文章鏈接:SpringBoot集成POI導出Execl表格之統一工具類。補中了一個Execl表格根據數量生成多個sheet(比如我們有10萬條數據導出Execl表格,且不說會不會內存溢出問題,一個表格存這個多數據要下拉框也要拉很長時間)
解決:我們可以在一個Execl表格中創建多個sheet分別來存放這些數據,這樣就解決了一些問題,也方便查看。
效果如下:
具體的jar包依賴等,在裏就不細說了,可以看上一篇文章:SpringBoot集成POI導出Execl表格之統一工具類
代碼:
//每個sheet最多導出多少條數據
public static final int SHEET_COUNT = 3;
/**
* 寫excel. 拆分多個sheet
* xls方式
* @param response 響應流
* @param fileName 文件名稱
* @param titleColumn 對應bean的屬性名
* @param titleName excel要導出的列名
* @param titleSize 列寬
* @param dataList 數據
*/
public static void writeExcel(HttpServletResponse response, String fileName, String titleColumn[], String titleName[], int titleSize[], List<?> dataList) {
//添加Worksheet(不添加sheet時生成的xls文件打開時會報錯)
HSSFWorkbook workbook = new HSSFWorkbook();
OutputStream out = null;
try{
//新建文件
out = response.getOutputStream();
String lastFileName = fileName + ".xls";
response.setContentType("application/msexcel;charset=UTF-8");
response.setHeader("Content-Disposition", "attachment; filename="
+ URLEncoder.encode(lastFileName, "UTF-8"));
int k = 0;
int rowIndex;
Sheet sheet = workbook.createSheet(fileName + (k + 1));
//寫入excel的表頭
Row titleNameRow = workbook.getSheet(fileName + (k + 1)).createRow(0);
//設置樣式
CellStyle titleStyle = workbook.createCellStyle();
for (int i = 0; i < titleName.length; i++) {
sheet.setColumnWidth(i, titleSize[i] * 256); //設置寬度
Cell cell = titleNameRow.createCell(i);
cell.setCellStyle(titleStyle);
cell.setCellValue(titleName[i]);
}
//通過反射獲取數據並寫入到excel中
if (dataList != null && dataList.size() > 0) {
if (titleColumn.length > 0) {
for (int index = 0; index < dataList.size(); index++) {
//設置多個sheet
//每個sheet3W條數據
if (index != 0 && (index) % SHEET_COUNT == 0) {
k = k + 1;
sheet = workbook.createSheet(fileName + (k + 1));
//寫入excel的表頭
titleNameRow = workbook.getSheet(fileName + (k + 1)).createRow(0);
for (int i = 0; i < titleName.length; i++) {
sheet.setColumnWidth(i, titleSize[i] * 256); //設置寬度
Cell cell = titleNameRow.createCell(i);
cell.setCellStyle(titleStyle);
cell.setCellValue(titleName[i]);
}
}
if (index < SHEET_COUNT) {
rowIndex = index + 1;
} else {
rowIndex = index - SHEET_COUNT * ((index) / SHEET_COUNT) + 1;
}
Object obj = dataList.get(index); //獲得該對象
Class clsss = obj.getClass(); //獲得該對對象的class實例
Row dataRow = workbook.getSheet(fileName + (k + 1)).createRow(rowIndex);
for (int columnIndex = 0; columnIndex < titleColumn.length; columnIndex++) {
String title = titleColumn[columnIndex].toString().trim();
if (!"".equals(title)) { //字段不爲空
//使首字母大寫
String UTitle = Character.toUpperCase(title.charAt(0)) + title.substring(1, title.length()); // 使其首字母大寫;
String methodName = "get" + UTitle;
// 設置要執行的方法
Method method = clsss.getDeclaredMethod(methodName);
//獲取返回類型
String returnType = method.getReturnType().getName();
Object object = method.invoke(obj);
String data = method.invoke(obj) == null ? "" : object.toString();
Cell cell = dataRow.createCell(columnIndex);
if (data != null && !"".equals(data)) {
if ("int".equals(returnType)) {
cell.setCellValue(Integer.parseInt(data));
} else if (Date.class.getName().equals(returnType)) {
cell.setCellValue(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(object));
} else {
cell.setCellValue(data);
}
}
}
}
}
}
}
workbook.write(out);
} catch (Exception e) {
e.printStackTrace();
} finally {
if (out != null) {
try {
out.flush();
out.close();
} catch (IOException e) {
logger.debug("導出寫Excel異常");
}
}
}
}
測試:
@RequestMapping("/export")
public void export(HttpServletResponse response) {
List<Object> dataList = new ArrayList<>();
User user1 = new User("張三", 23, "男", 173);
User user2 = new User("李四", 20, "男", 183);
User user3 = new User("王五", 25, "男", 165);
User user4 = new User("小花", 18, "女", 165);
dataList.add(user1);
dataList.add(user2);
dataList.add(user3);
dataList.add(user4);
//多次填充測試數據
dataList.add(user1);
dataList.add(user2);
dataList.add(user3);
dataList.add(user4);
dataList.add(user1);
dataList.add(user2);
dataList.add(user3);
dataList.add(user4);
try {
//導出xsl格式(拆分多個sheet)
ExcelExportUtil.writeExcel(response, "用戶信息導出數據",new String[]{"name", "age", "sex", "height"}
, new String[]{"姓名", "年齡", "性別", "身高"}
, new int[]{30, 30, 30, 30}, dataList);
} catch (Exception e) {
e.printStackTrace();
}
}
上一篇中也有拆分多個sheet的代碼,但導出格式爲(SXSSFWorkbook)xlsx的格式,本篇說明的是(HSSFWorkbook)xls的格式。