Java操作Excel文件解析与读写方法详解

try (Workbook workbook = new XSSFWorkbook();
				FileOutputStream fos = new FileOutputStream("c:\\test\\temp.xlsx")) {
    workbook.write(fos);
} catch (IOException e) {
    e.printStackTrace();
}

// 输入流
FileInputStream fis = new FileInputStream("c:\\test\\1627356554991.xlsx");
// Excel文件对象
Workbook workbook = new XSSFWorkbook(fis);

// 按照默认名称创建工作簿
Sheet sheet1 = workbook.createSheet();
// 按照自定义名称创建工作簿
Sheet sheet2 = workbook.createSheet("自定义工作簿2");

// 按照工作簿下标获取Sheet
Sheet sheet01 = workbook.getSheetAt(0);
// 按照工作簿名称获取Sheet
Sheet sheet02 = workbook.getSheet("Sheet0");

int n = workbook.getNumberOfSheets();

Row row = sheet.createRow(0);

int first = sheet.getFirstRowNum();
int last = sheet.getLastRowNum();

Row row = sheet.getRow(0);

for(Row row : sheet) {
    System.out.println(row);
}

for (int i = 1; i <= sheet.getLastRowNum(); i++) {
    Row row = sheet.getRow(i);
    System.out.println(row);
}

Cell cell0 = row.createCell(0);

cell0.setCellValue(UUID.randomUUID().toString());

Cell cell = row.getCell(1);

for(Cell cell : row) {}

CellType type = cell.getCellType();

// 创建单元格样式
DataFormat dataFormat = workbook.createDataFormat();
Short formatCode = dataFormat.getFormat("yyyy-MM-dd HH:mm:ss");
CellStyle cellStyle = workbook.createCellStyle();
cellStyle.setDataFormat(formatCode);
// 为当前行创建单元格
Cell cell1 = row.createCell(1);
cell1.setCellStyle(cellStyle); // 设置单元格样式
cell1.setCellValue(new Date()); // 保存当前日期时间至本单元格

// 创建单元格样式
CellStyle cellStyle = workbook.createCellStyle();
//设置单元格的水平对齐类型。 此时水平居中
cellStyle.setAlignment(HorizontalAlignment.CENTER);
// 设置单元格的垂直对齐类型。 此时垂直靠底边
cellStyle.setVerticalAlignment(VerticalAlignment.BOTTOM);

try (Workbook workbook = new SXSSFWorkbook(100);
				FileOutputStream fos = new FileOutputStream("c:\\test\\temp.xlsx")) {
    Sheet sheet1 = workbook.createSheet();
    for (int i = 0; i <= 1000000; i++) {
        Row row = sheet1.createRow(i);
        Cell cell0 = row.createCell(0);
        cell0.setCellValue(UUID.randomUUID().toString());
        Cell cell1 = row.createCell(1);
        cell1.setCellValue(new Date());
    }
    workbook.write(fos);
} catch (IOException e) {
    e.printStackTrace();
}

//准备实体类
public class Order {
    @ExcelProperty("订单编号")
	private String orderId; // 订单编号
    @ExcelProperty("支付金额")
	@NumberFormat("￥#,###")
	private Double payment; // 支付金额
    @ExcelProperty(value = "创建日期",converter = LocalDateTimeConverter.class)
	private LocalDateTime creationTime; // 创建时间
	public Order() {
		this.orderId = LocalDateTime.now().format(DateTimeFormatter.ofPattern("yyyyMMddhhmmss"))
				+ UUID.randomUUID().toString().substring(0, 5);
		this.payment = Math.random() * 10000;
		this.creationTime = LocalDateTime.now();
	}
	public String getOrderId() {
		return orderId;
	}
	public void setOrderId(String orderId) {
		this.orderId = orderId;
	}
	public Double getPayment() {
		return payment;
	}
	public void setPayment(Double payment) {
		this.payment = payment;
	}
	public LocalDateTime getCreationTime() {
		return creationTime;
	}
	public void setCreationTime(LocalDateTime creationTime) {
		this.creationTime = creationTime;
	}
	@Override
	public String toString() {
		return "Order [orderId=" + orderId + ", payment=" + payment + ", creationTime=" + creationTime + "]";
	}
}

//准备Converter转换类
public class LocalDateTimeConverter implements Converter<LocalDateTime> {
	@Override
	public Class<LocalDateTime> supportJavaTypeKey() {
		return LocalDateTime.class;
	}
	@Override
	public CellDataTypeEnum supportExcelTypeKey() {
		return CellDataTypeEnum.STRING;
	}
	@Override
	public LocalDateTime convertToJavaData(CellData cellData, ExcelContentProperty contentProperty,
			GlobalConfiguration globalConfiguration) {
		return LocalDateTime.parse(cellData.getStringValue(), DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"));
	}
	@Override
	public CellData<String> convertToExcelData(LocalDateTime value, ExcelContentProperty contentProperty,
			GlobalConfiguration globalConfiguration) {
		return new CellData<>(value.format(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")));
	}
}

import java.util.ArrayList;
import java.util.List;
import com.alibaba.excel.EasyExcel;
public class Demo01 {
	public static void main(String[] args) {
		long begin = System.currentTimeMillis();
		// 写入100w
        EasyExcel.write("D:\\java.workspace\\1000W.xlsx", Order.class)
                 .sheet("订单列表")
                 .doWrite(data());
        long end = System.currentTimeMillis();
		System.out.println("共耗时"+(end-begin)+"毫秒");
    }
    // 创建100w条订单数据
    private static List<Order> data() {
        List<Order> list = new ArrayList<Order>();
        for (int i = 0; i < 1000000; i++) {
            list.add(new Order());
        }
        return list;
    }
}

import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import com.alibaba.excel.EasyExcel;
import com.alibaba.excel.context.AnalysisContext;
import com.alibaba.excel.event.AnalysisEventListener;
public class Demo02 {
	public static void main(String[] args) {
		//用于保存读取到的结果
		List<Order> orderList = new ArrayList<Order>();
		//读取
		EasyExcel.read("D:\\java.workspace\\1000W.xlsx", Order.class,new AnalysisEventListener<Order>() {
		    @Override
		    public void invoke(Order order, AnalysisContext arg1) {
		        // 读取每条数据
		        orderList.add(order);
		    }
		    @Override
		    public void invokeHeadMap(Map<Integer, String> headMap, AnalysisContext context) {
		        // 读取到列头
		        System.out.println(headMap);
		    }
		    @Override
		    public void doAfterAllAnalysed(AnalysisContext arg0) {
		        // 读取完毕
		        System.out.println("END");
		    }
		}).sheet().doRead();
		//遍历
		for(Order order : orderList) {
			System.out.println(order);
		}
	}
}