注意
SXSSFWorkbook 用於大量數據的導出
SXSSFWorkbook是用來生成海量excel數據文件,主要原理是藉助臨時存儲空間生成excel, SXSSFWorkbook專門處理大數據,對於大型excel的創建且不會內存溢出的,就只SXSSFWorkbook了。
它的原理很簡單,用硬盤空間換內存(就像hashmap用空間換時間一樣)。 SXSSFWorkbook是streaming 版本的XSSFWorkbook,它只會保存最新的excel rows在內存裏供查看,在此之前的excel rows都會被寫入到硬盤裏(Windows電腦的話,是寫入到C盤根目錄下的temp文件夾)。被寫入到硬盤裏的rows是不可見的/不可訪問的。只有還保存在內存裏的纔可以被訪問到。
注:HSSFWorkbook和XSSFWorkbook的Excel Sheet導出條數上限(<=2003版)是65535行、256列,(>=2007版) 是1048576行,16384列,如果數據量超過了此上限,那麼可以使用SXSSFWorkbook來導出。實際上上萬條數據,甚至上千條數據就可以考慮使用SXSSFWorkbook了。
注意:首先需要引入依賴:注意:4.0.0版本的JDK需要1.8以上,如果JDK是1.7的,那麼就使用3.9版本的依賴
- SXSSFWorkbook基於模板寫入數據的時候仍需要藉助XSSFWorkbook
- SXSSFWorkbook寫入數據模式大致爲:根據初始化設置的flushRows(內存存儲條數)數隨着數據寫入逐步把數據刷新至硬盤,具體參考官方文檔與API介紹
XSSFWorkbook tplWorkBook = new XSSFWorkbook(new FileInputStream(file));
writeDataWorkBook = new SXSSFWorkbook(tplWorkBook, flushRows);
代碼案例
package com.user.base.util.Excel.POI;
import org.apache.poi.hssf.usermodel.HSSFDataFormat;
import org.apache.poi.hssf.util.HSSFColor;
import org.apache.poi.ss.usermodel.*;
import org.apache.poi.ss.util.CellRangeAddress;
import org.apache.poi.xssf.streaming.SXSSFSheet;
import org.apache.poi.xssf.streaming.SXSSFWorkbook;
import org.apache.poi.xssf.usermodel.XSSFCellStyle;
import org.apache.poi.xssf.usermodel.XSSFFont;
import org.apache.poi.xssf.usermodel.XSSFRichTextString;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import java.io.*;
import java.text.SimpleDateFormat;
import java.util.*;
/**
* @author :mmzs
* @date :Created in 2020/3/29 9:59
* @description:大量數據導出
* @modified By:
* @version: 1$
*
* Excel 相關操作類(大數據量寫入但受Excel數據行數限制)
* 先寫入Excel標題(writeExcelTitle),再寫入數據(writeExcelData),最後釋放資源(dispose)
*/
public class ExportExcel2007 {
//默認列寬度
private final int DEFAULT_COLUMN_SIZE = 30;
//刷新寫入硬盤數據閥值
private final int flushRows = 1000;
//聲明一個模板工作薄(寫入流式數據)
private Workbook writeDataWorkBook;
//樣式列表
private Map<String, CellStyle> cellStyleMap;
//Excel當前數據行數(將要寫入數據的索引數)
private int currentRowNum = 0;
//數據輸出流
private OutputStream outputStream;
/**
* 斷言Excel文件寫入之前的條件
*
* @param directory 目錄
* @param fileName 文件名
* @return file
* @throws IOException
*/
private File assertFile(String directory, String fileName) throws IOException {
File tmpFile = new File(directory + File.separator + fileName + ".xlsx");
if (tmpFile.exists()) {
if (tmpFile.isDirectory()) {
throw new IOException("File '" + tmpFile + "' exists but is a directory");
}
if (!tmpFile.canWrite()) {
throw new IOException("File '" + tmpFile + "' cannot be written to");
}
} else {
File parent = tmpFile.getParentFile();
if (parent != null) {
if (!parent.mkdirs() && !parent.isDirectory()) {
throw new IOException("Directory '" + parent + "' could not be created");
}
}
}
return tmpFile;
}
/**
* 日期轉化爲字符串,格式爲yyyy-MM-dd HH:mm:ss
*/
private String getCnDate(Date date) {
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
return sdf.format(date);
}
/**
* Excel 導出,POI實現,先寫入Excel標題,與writeExcelData配合使用
* 先使用writeExcelTitle再使用writeExcelData
*
* @param directory 目錄
* @param fileName 文件名
* @param sheetName sheetName
* @param columnNames 列名集合
* @param sheetTitle 表格標題
*/
public void writeExcelTitle(String directory, String fileName, String sheetName, List<String> columnNames,
String sheetTitle) throws IOException {
File tmpFile = assertFile(directory, fileName);
exportExcelTitle(tmpFile, sheetName, columnNames, sheetTitle);
loadTplWorkbook(tmpFile);
}
/**
* Excel 導出,POI實現,寫入Excel數據行列,與writeExcelTitle配合使用
* 先使用writeExcelTitle再使用writeExcelData
*
* @param directory 目錄
* @param fileName 文件名
* @param sheetName sheetName
* @param objects 數據信息
*/
public void writeExcelData(String directory, String fileName, String sheetName, List<List<Object>> objects)
throws IOException {
File tmpFile = assertFile(directory, fileName);
outputStream = new FileOutputStream(tmpFile);
exportExcelData(sheetName, objects);
}
/**
* 釋放資源
*/
public void dispose() {
try {
if (writeDataWorkBook != null) {
writeDataWorkBook.write(outputStream);
}
if (outputStream != null) {
outputStream.flush();
outputStream.close();
}
if (cellStyleMap != null) {
cellStyleMap.clear();
}
cellStyleMap = null;
outputStream = null;
writeDataWorkBook = null;
} catch (IOException e) {
e.printStackTrace();
}
}
/**
* 導出字符串數據
*
* @param file 文件名
* @param columnNames 表頭
* @param sheetTitle sheet頁Title
*/
private void exportExcelTitle(File file, String sheetName, List<String> columnNames,
String sheetTitle) {
Workbook tplWorkBook = new XSSFWorkbook();
Map<String, CellStyle> cellStyleMap = styleMap(tplWorkBook);
// 表頭樣式
CellStyle headStyle = cellStyleMap.get("head");
// 生成一個表格
Sheet sheet = tplWorkBook.getSheet(sheetName);
if (sheet == null) {
sheet = tplWorkBook.createSheet(sheetName);
}
//最新Excel列索引,從0開始
//int lastRowIndex = sheet.getLastRowNum();
// 設置表格默認列寬度
sheet.setDefaultColumnWidth(DEFAULT_COLUMN_SIZE);
// 合併單元格
sheet.addMergedRegion(new CellRangeAddress(currentRowNum, currentRowNum, 0, columnNames.size() - 1));
// 產生表格標題行
Row rowMerged = sheet.createRow(currentRowNum);
Cell mergedCell = rowMerged.createCell(0);
mergedCell.setCellStyle(headStyle);
mergedCell.setCellValue(new XSSFRichTextString(sheetTitle));
//寫入成功一行數據遞增行數
currentRowNum = currentRowNum + 1;
// 產生表格表頭列標題行
Row row = sheet.createRow(currentRowNum);
for (int i = 0; i < columnNames.size(); i++) {
Cell cell = row.createCell(i);
cell.setCellStyle(headStyle);
RichTextString text = new XSSFRichTextString(columnNames.get(i));
cell.setCellValue(text);
}
//寫入成功一行數據遞增行數
currentRowNum = currentRowNum + 1;
try {
OutputStream ops = new FileOutputStream(file);
tplWorkBook.write(ops);
ops.flush();
ops.close();
} catch (IOException e) {
e.printStackTrace();
}
}
/**
* 加載模板文件
*/
private void loadTplWorkbook(File file) {
try {
XSSFWorkbook tplWorkBook = new XSSFWorkbook(new FileInputStream(file));
writeDataWorkBook = new SXSSFWorkbook(tplWorkBook, flushRows);
cellStyleMap = styleMap(writeDataWorkBook);
} catch (IOException e) {
e.printStackTrace();
}
}
/**
* 導出字符串數據
*
* @param objects 目標數據
*/
private void exportExcelData(String sheetName, List<List<Object>> objects) throws IOException {
// 正文樣式
CellStyle contentStyle = cellStyleMap.get("content");
//正文整數樣式
CellStyle contentIntegerStyle = cellStyleMap.get("integer");
//正文帶小數整數樣式
CellStyle contentDoubleStyle = cellStyleMap.get("double");
// 生成一個表格
Sheet sheet = writeDataWorkBook.getSheet(sheetName);
if (sheet == null) {
// throw new ReportInternalException("讀取Excel模板錯誤");
}
// 設置表格默認列寬度
sheet.setDefaultColumnWidth(DEFAULT_COLUMN_SIZE);
// 遍歷集合數據,產生數據行,前兩行爲標題行與表頭行
for (List<Object> dataRow : objects) {
Row row = sheet.createRow(currentRowNum);
for (int j = 0; j < dataRow.size(); j++) {
Cell contentCell = row.createCell(j);
Object dataObject = dataRow.get(j);
if (dataObject != null) {
if (dataObject instanceof Integer) {
contentCell.setCellStyle(contentIntegerStyle);
contentCell.setCellValue(Integer.parseInt(dataObject.toString()));
} else if (dataObject instanceof Double) {
contentCell.setCellStyle(contentDoubleStyle);
contentCell.setCellValue(Double.parseDouble(dataObject.toString()));
} else if (dataObject instanceof Long && dataObject.toString().length() == 13) {
contentCell.setCellStyle(contentStyle);
contentCell.setCellValue(getCnDate(new Date(Long.parseLong(dataObject.toString()))));
} else if (dataObject instanceof Date) {
contentCell.setCellStyle(contentStyle);
contentCell.setCellValue(getCnDate((Date) dataObject));
} else {
contentCell.setCellStyle(contentStyle);
contentCell.setCellValue(dataObject.toString());
}
} else {
contentCell.setCellStyle(contentStyle);
// 設置單元格內容爲字符型
contentCell.setCellValue("");
}
}
//寫入成功一行數據遞增行數
currentRowNum = currentRowNum + 1;
}
try {
((SXSSFSheet) sheet).flushRows(flushRows);
} catch (IOException e) {
e.printStackTrace();
}
}
/**
* 創建單元格表頭樣式
*
* @param workbook 工作薄
*/
private CellStyle createCellHeadStyle(Workbook workbook) {
CellStyle style = workbook.createCellStyle();
// 設置邊框樣式
style.setBorderBottom(XSSFCellStyle.BORDER_THIN);
style.setBorderLeft(XSSFCellStyle.BORDER_THIN);
style.setBorderRight(XSSFCellStyle.BORDER_THIN);
style.setBorderTop(XSSFCellStyle.BORDER_THIN);
//設置對齊樣式
style.setAlignment(XSSFCellStyle.ALIGN_CENTER);
// 生成字體
Font font = workbook.createFont();
// 表頭樣式
style.setFillPattern(XSSFCellStyle.SOLID_FOREGROUND);
style.setFillForegroundColor(HSSFColor.GREY_25_PERCENT.index);
font.setFontHeightInPoints((short) 12);
font.setBoldweight(XSSFFont.BOLDWEIGHT_BOLD);
// 把字體應用到當前的樣式
style.setFont(font);
return style;
}
/**
* 創建單元格正文樣式
*
* @param workbook 工作薄
*/
private CellStyle createCellContentStyle(Workbook workbook) {
CellStyle style = workbook.createCellStyle();
// 設置邊框樣式
style.setBorderBottom(XSSFCellStyle.BORDER_THIN);
style.setBorderLeft(XSSFCellStyle.BORDER_THIN);
style.setBorderRight(XSSFCellStyle.BORDER_THIN);
style.setBorderTop(XSSFCellStyle.BORDER_THIN);
//設置對齊樣式
style.setAlignment(XSSFCellStyle.ALIGN_CENTER);
// 生成字體
Font font = workbook.createFont();
// 正文樣式
style.setFillPattern(XSSFCellStyle.NO_FILL);
style.setVerticalAlignment(XSSFCellStyle.VERTICAL_CENTER);
font.setBoldweight(XSSFFont.BOLDWEIGHT_NORMAL);
// 把字體應用到當前的樣式
style.setFont(font);
return style;
}
/**
* 單元格樣式(Integer)列表
*/
private CellStyle createCellContent4IntegerStyle(Workbook workbook) {
CellStyle style = workbook.createCellStyle();
// 設置邊框樣式
style.setBorderBottom(XSSFCellStyle.BORDER_THIN);
style.setBorderLeft(XSSFCellStyle.BORDER_THIN);
style.setBorderRight(XSSFCellStyle.BORDER_THIN);
style.setBorderTop(XSSFCellStyle.BORDER_THIN);
//設置對齊樣式
style.setAlignment(XSSFCellStyle.ALIGN_CENTER);
// 生成字體
Font font = workbook.createFont();
// 正文樣式
style.setFillPattern(XSSFCellStyle.NO_FILL);
style.setVerticalAlignment(XSSFCellStyle.VERTICAL_CENTER);
font.setBoldweight(XSSFFont.BOLDWEIGHT_NORMAL);
// 把字體應用到當前的樣式
style.setFont(font);
style.setDataFormat(HSSFDataFormat.getBuiltinFormat("#,##0"));//數據格式只顯示整數
return style;
}
/**
* 單元格樣式(Double)列表
*/
private CellStyle createCellContent4DoubleStyle(Workbook workbook) {
CellStyle style = workbook.createCellStyle();
// 設置邊框樣式
style.setBorderBottom(XSSFCellStyle.BORDER_THIN);
style.setBorderLeft(XSSFCellStyle.BORDER_THIN);
style.setBorderRight(XSSFCellStyle.BORDER_THIN);
style.setBorderTop(XSSFCellStyle.BORDER_THIN);
//設置對齊樣式
style.setAlignment(XSSFCellStyle.ALIGN_CENTER);
// 生成字體
Font font = workbook.createFont();
// 正文樣式
style.setFillPattern(XSSFCellStyle.NO_FILL);
style.setVerticalAlignment(XSSFCellStyle.VERTICAL_CENTER);
font.setBoldweight(XSSFFont.BOLDWEIGHT_NORMAL);
// 把字體應用到當前的樣式
style.setFont(font);
style.setDataFormat(HSSFDataFormat.getBuiltinFormat("#,##0.00"));//保留兩位小數點
return style;
}
/**
* 單元格樣式列表
*/
private Map<String, CellStyle> styleMap(Workbook workbook) {
Map<String, CellStyle> styleMap = new LinkedHashMap<>();
styleMap.put("head", createCellHeadStyle(workbook));
styleMap.put("content", createCellContentStyle(workbook));
styleMap.put("integer", createCellContent4IntegerStyle(workbook));
styleMap.put("double", createCellContent4DoubleStyle(workbook));
return styleMap;
}
public static void main(String[] args) throws IOException {
String sheetName = "測試Excel格式";
String sheetTitle = "測試Excel格式";
List<String> columnNames = new LinkedList<>();
columnNames.add("日期-String");
columnNames.add("日期-Date");
columnNames.add("時間戳-Long");
columnNames.add("客戶編碼");
columnNames.add("整數");
columnNames.add("帶小數的正數");
ExportExcel2007 exportExcel2007 = new ExportExcel2007();
exportExcel2007.writeExcelTitle("D:\\export", "b", sheetName, columnNames, sheetTitle);
for (int j = 0; j < 2; j++) {
List<List<Object>> objects = new LinkedList<>();
for (int i = 0; i < 1000; i++) {
List<Object> dataA = new LinkedList<>();
dataA.add("2016-09-05 17:27:25");
dataA.add(new Date(1451036631012L));
dataA.add(1451036631012L);
dataA.add("000628");
dataA.add(i);
dataA.add(1.323 + i);
objects.add(dataA);
}
try {
exportExcel2007.writeExcelData("D:\\export", "b", sheetName, objects);
} catch (Exception e) {
e.printStackTrace();
}
objects.clear();
}
exportExcel2007.dispose();
}
}