前言
文章目录
demo代码:https://github.com/RwTo/excel-demo
JAVA解析Excel 一般有三种方式
JExcelAPI
POI
EasyExcel
JExcelAPI
官网:https://jexcelapi.sourceforge.net/
- 仅支持 2003 版本的Excel 也就是 后缀名为 xls 的文件
- 采用流式处理模型,逐行读取和写入 ------因此 可以处理大量数据,一般不会出现OOM
Demo
xml
<!--JExcelAPI-->
<dependency>
<groupId>net.sourceforge.jexcelapi</groupId>
<artifactId>jxl</artifactId>
<version>2.6.12</version>
</dependency>
读xls 文件
java
public class ReadExcelDemo {
public static void main(String[] args) {
try {
// 1. 打开 Excel 文件
String filePath = ExcelConstant.EXCEL_PATH_XLS;
Workbook workbook = Workbook.getWorkbook(new java.io.File(filePath));
// 2. 获取第一个工作表
Sheet sheet = workbook.getSheet(0);
/**
* -Xms64m -Xmx64m
* row = 4000 col = 50
* 正常读
*/
// 3. 遍历每一行,并读取数据
for (int row = 0; row < sheet.getRows(); row++) {
for (int col = 0; col < sheet.getColumns(); col++) {
Cell cell = sheet.getCell(col, row);
String content = cell.getContents();
content += cell.getCellFormat().getBackgroundColour().getDescription();
System.out.print(content+"\t");
}
System.out.println();
}
// 4. 关闭工作簿
workbook.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
写xls 文件
java
public class WriteExcelDemo {
public static void main(String[] args) {
try {
String filePath = ExcelConstant.EXCEL_PATH_XLS;
// 1. 创建工作簿
WritableWorkbook workbook = Workbook.createWorkbook(new File(filePath));
// 2. 创建工作表
WritableSheet sheet = workbook.createSheet("Sheet1", 0);
// 3. 定义单元格颜色
WritableCellFormat greenFormat = new WritableCellFormat();
greenFormat.setBackground(jxl.format.Colour.GREEN);
WritableCellFormat yellowFormat = new WritableCellFormat();
yellowFormat.setBackground(jxl.format.Colour.YELLOW);
/**
* -Xms64m -Xmx64m
* row = 4000 col = 50
* 正常写
*/
// 4. 写入数据
for (int row = 0; row < 4000; row++) {
for (int col = 0; col < 50; col++) {
if(col%2 == 0){
Label label = new Label(col, row, "Cell " + (row + 1) + "-" + (col + 1),yellowFormat);
sheet.addCell(label);
}else{
Label label = new Label(col, row, "Cell " + (row + 1) + "-" + (col + 1),greenFormat);
sheet.addCell(label);
}
}
}
// 5. 保存工作簿
workbook.write();
workbook.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
POI
功能比较丰富,使用较为广泛,问题也比较多(比如OOM)
四种API 操作Excel
官网介绍:https://poi.apache.org/components/spreadsheet/how-to.html
文档对象模型
HSSFWorkBook (功能丰富,但会OOM)
XSSFWorkBook (功能丰富,但易OOM)
事件处理模型(流式处理)
SXSSFWorkBook (只支持xlsx 的写入)
XSSFReader(仅提供模板,需要使用者自己编写)
POM 文件
xml
<!-- Apache POI -->
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi</artifactId>
<version>4.1.2</version>
</dependency>
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi-ooxml</artifactId>
<version>4.1.2</version>
</dependency>
HSSFWorkBook
- 支持 xls 文件的解析和写入
- 基于DOM ,将整个 Excel 文件加载到内存中,构建一个完整的 Excel 文档对象模型树,再进行解析和操作,当文件较大时,可能会出现内存溢出
但因为 xls 文件支持的样式和单元格数量较少,一般不会出现OOM
XSSFWorkBook
- 支持 xlsx 文件的解析和写入
- 基于DOM ,将整个 Excel 文件加载到内存中,构建一个完整的 Excel 文档对象模型树,再进行解析和操作,当文件较大时,可能会出现内存溢出
Demo
写入excel(xls,xlsx)
java
public class WriteExcelDemo {
public static void main(String[] args) {
try {
String filePath = ExcelConstant.EXCEL_PATH_XLS;
//String filePath = ExcelConstant.EXCEL_PATH_XLSX;
//Workbook workbook = new XSSFWorkbook(); //支持xlsx文件的写入
Workbook workbook = new HSSFWorkbook(); //支持xls文件的写入
Sheet sheet = workbook.createSheet("Sheet1");
/**
* -Xms64m -Xmx64m
* row = 4000 col = 50
* 出现OOM
*/
for (int row = 0; row < 4000; row++) {
Row excelRow = sheet.createRow(row);
for (int col = 0; col < 50; col++) {
Cell cell = excelRow.createCell(col);
cell.setCellValue("Cell " + (row + 1) + "-" + (col + 1));
}
}
FileOutputStream fileOutputStream = new FileOutputStream(filePath);
workbook.write(fileOutputStream);
fileOutputStream.close();
workbook.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
读excel(xls,xlsx)
java
public class ReadExcelDemo {
public static void main(String[] args) {
try {
String filePath = ExcelConstant.EXCEL_PATH_XLSX;
//String filePath = ExcelConstant.EXCEL_PATH_XLSX;
FileInputStream fileInputStream = new FileInputStream(filePath);
//WorkbookFactory会根据文件类型自动选择使用HSSFWorkBook 或 XSSFWorkBook
Workbook workbook = WorkbookFactory.create(fileInputStream);
Sheet sheet = workbook.getSheetAt(0);
/**
* -Xms64m -Xmx64m
* row = 4000 col = 50
* 出现OOM
*/
for (Row row : sheet) {
for (Cell cell : row) {
String cellValue = getCellValueAsString(cell);
System.out.print(cellValue + "\t");
}
System.out.println();
}
fileInputStream.close();
workbook.close();
} catch (Exception e) {
e.printStackTrace();
}
}
private static String getCellValueAsString(Cell cell) {
if (cell == null) {
return "";
}
switch (cell.getCellType()) {
case STRING:
return cell.getStringCellValue();
case NUMERIC:
return String.valueOf(cell.getNumericCellValue());
case BOOLEAN:
return String.valueOf(cell.getBooleanCellValue());
default:
return "";
}
}
}
SXSSFWorkBook
- 仅支持xlsx 的写入
- 基于流式处理,逐行对excel 处理,用磁盘空间换取内存,可以高效地写入数据到 Excel 文件中,同时减少内存占用。
- SXSSFWorkbook 采用了内存优化的设计,避免了将所有数据加载到内存的需求。它仅将有限数量的行缓冲在内存中,写入到输出流后即丢弃缓冲的数据,从而减少了内存占用。
- SXSSFWorkbook 支持设置在写入数据之前保留在内存中的行数。通过控制分页大小,可以灵活地控制内存使用,特别适合处理超大型的 Excel 文件。
Demo
写入xlsx
java
public class SXSSFWriteExcelDemo {
public static void main(String[] args) {
try {
// Set custom temporary directory
String customTempDirPath = "temp";
System.setProperty("java.io.tmpdir", customTempDirPath);
String filePath = ExcelConstant.EXCEL_PATH_XLSX_BIG;
SXSSFWorkbook workbook = new SXSSFWorkbook(500);//rowAccessWindowSize为内存中缓存的记录数,默认100
Sheet sheet = workbook.createSheet("Sheet1");
for (int row = 0; row < 100000; row++) {
Row excelRow = sheet.createRow(row);
for (int col = 0; col < 3; col++) {
Cell cell = excelRow.createCell(col);
cell.setCellValue("Cell " + (row + 1) + "-" + (col + 1));
}
}
FileOutputStream fileOutputStream = new FileOutputStream(filePath);
workbook.write(fileOutputStream);
fileOutputStream.close();
//使用 dispose() 方法释放(删除) SXSSFWorkbook 使用的临时资源,特别是在写入大量数据后,这一步骤很重要。
workbook.dispose();
/*如果不手动释放,默认等虚拟机停止也会删除临时文件
poi.keep.tmp.files 通过这个配置可以控制虚拟机停止时,不删除临时文件*/
//程序执行结束后,手动删除临时文件目录(看是否需要)
deleteTempFiles(new File(customTempDirPath));
} catch (Exception e) {
e.printStackTrace();
}
}
private static void deleteTempFiles(File directory) {
if (directory.isDirectory()) {
File[] files = directory.listFiles();
if (files != null) {
for (File file : files) {
deleteTempFiles(file);
}
}
}
if (!directory.delete()) {
System.err.println("Failed to delete temp file: " + directory.getAbsolutePath());
} else {
System.out.println("Deleted temp file: " + directory.getAbsolutePath());
}
}
}
XSSFReader
官网案例:https://poi.apache.org/components/spreadsheet/how-to.html#xssf_sax_api
- 仅支持 xlsx 的解析
- 基于流式处理,逐行读取单元格,不会将整个excel 存到内存,适合大型excel的处理
Demo
读xlsx
java
public class SAXWriteExcelDemo {
public static void main(String[] args) throws Exception {
String filePath = ExcelConstant.EXCEL_PATH_XLSX_BIG;
InputStream is = new FileInputStream(filePath);
OPCPackage opcPackage = OPCPackage.open(is);
try {
// 读取 Excel 文件
XSSFReader reader = new XSSFReader(opcPackage);
// 使用事件处理器处理 Sheet 数据
SAXSheetHandler sheetHandler = new SAXSheetHandler();
XSSFSheetXMLHandler xmlHandler = new XSSFSheetXMLHandler(reader.getStylesTable(), reader.getSharedStringsTable(), sheetHandler, false);
XMLReader sheetParser = XMLReaderFactory.createXMLReader();
sheetParser.setContentHandler(xmlHandler);
Iterator<InputStream> sheetsData = reader.getSheetsData();
while(sheetsData.hasNext()){
InputStream sheetIs = sheetsData.next();
InputSource sheet = new InputSource(sheetIs);
//开始解析sheet页
System.out.println("=====================================开始处理sheet页==============================================");
long start = System.currentTimeMillis();
sheetParser.parse(sheet);
System.out.println("=====================================处理sheet结束==============================================");
long end = System.currentTimeMillis();
List<List<SAXCell>> curSheet = sheetHandler.getCurSheet();
curSheet.forEach(System.out::println);
System.out.println("处理行数:"+sheetHandler.getRowCount());
System.out.println("处理单元格数:"+sheetHandler.getCellCount());
System.out.println("处理时间(ms):"+(end-start));
sheetHandler.clear();
}
} catch (IOException e) {
e.printStackTrace();
} catch (OpenXML4JException e) {
e.printStackTrace();
} catch (SAXException e) {
e.printStackTrace();
}finally {
// 关闭输入流和 OPCPackage
is.close();
opcPackage.close();
}
}
}
class SAXSheetHandler implements XSSFSheetXMLHandler.SheetContentsHandler {
//当前页
private List<List<SAXCell>> curSheet;
//当前行
private List<SAXCell> curRow;
//总单元格数
private int cellCount;
public SAXSheetHandler() {
this.curSheet = new LinkedList<>();
}
/**
* 一行处理开始时
*
* @param i 行号
*/
@Override
public void startRow(int i) {
//开始处理新的一行,初始化当前行
curRow = new LinkedList<>();
}
/**
* 一行处理结束时
*
* @param i 行号
*/
@Override
public void endRow(int i) {
//一行处理结束,将这一行数据存入sheet
curSheet.add(curRow);
}
/**
* 处理单元格(不会读取空单元格)
*
* @param cellReference 单元格名称
* @param formattedValue 单元格值
* @param xssfComment 批注
*/
@Override
public void cell(String cellReference, String formattedValue, XSSFComment xssfComment) {
SAXCell cell = new SAXCell(cellReference, formattedValue);
curRow.add(cell);
cellCount++;
}
@Override
public void headerFooter(String text, boolean isHeader, String tagName) {
// 头部和页脚
}
@Override
public void endSheet() {
//sheet处理结束
}
public List<List<SAXCell>> getCurSheet() {
return curSheet;
}
public int getCellCount() {
return cellCount;
}
public int getRowCount() {
return curSheet.size();
}
public void clear(){
curSheet = new LinkedList<>();
cellCount = 0;
}
}
@Data
class SAXCell {
private String cellName;
private String value;
public SAXCell(String cellName, String value) {
this.cellName = cellName;
this.value = value;
}
}
EasyExcel
官网:https://easyexcel.opensource.alibaba.com/
- 支持xlsx和xls 文件的解析和写入
- 流式处理,节省内存,可以处理大型excel
- 支持注解,简单易用
Demo
POM
xml
<!--easyExcel-->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>easyexcel</artifactId>
<version>2.2.0-beta2</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
</dependency>
实例
java
@Data
public class UserData {
private String name;
private int age;
private String email;
public UserData() {
}
public UserData(String name, int age, String email) {
this.name = name;
this.age = age;
this.email = email;
}
}
写入excel(xls,xlsx)
java
public class EasyWriteExcelDemo {
public static void main(String[] args) {
String filePath = ExcelConstant.EE_EXCEL_PATH_XLSX_BIG;
// 创建写入的数据列表
List<UserData> dataList = new ArrayList<>();
dataList.add(new UserData("Alice", 25, "alice@example.com"));
dataList.add(new UserData("Bob", 30, "bob@example.com"));
dataList.add(new UserData("Charlie", 28, "charlie@example.com"));
// 使用 EasyExcel 写入 Excel 文件
EasyExcel.write(filePath, UserData.class).sheet("Sheet1").doWrite(dataList);
}
}
读取excel(xls,xlsx)
java
public class EasyReadExcelDemo {
public static void main(String[] args) {
String filePath = ExcelConstant.EE_EXCEL_PATH_XLSX_BIG;
// 使用 EasyExcel 读取 Excel 文件
EasyExcel.read(filePath, UserData.class, new UserDataListener()).sheet().doRead();
}
public static class UserDataListener extends AnalysisEventListener<UserData> {
private List<UserData> dataList = new ArrayList<>();
@Override
public void invoke(UserData data, AnalysisContext context) {
dataList.add(data);
}
@Override
public void doAfterAllAnalysed(AnalysisContext context) {
// 在这里可以对 dataList 中的数据进行处理,比如保存到数据库或其他操作
for (UserData userData : dataList) {
System.out.println(userData.getName() + "\t" + userData.getAge() + "\t" + userData.getEmail());
}
}
}
}