一：分多次将数据写入EXCEL

1：这种方式效率比较低，数据量越大越明显，4万条数据要2分钟左右

package com.test;import java.io.BufferedOutputStream;import java.io.File;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;import org.apache.poi.openxml4j.exceptions.InvalidFormatException;import org.apache.poi.xssf.usermodel.XSSFRow;import org.apache.poi.xssf.usermodel.XSSFSheet;import org.apache.poi.xssf.usermodel.XSSFWorkbook;public class POIController {	/**	 * 这种方式效率比较低，数据量越大越明显，4万条数据要2分钟左右	 * @param args	 * @throws FileNotFoundException	 * @throws InvalidFormatException	 */	public static void main(String[] args) throws FileNotFoundException, InvalidFormatException {		long startTime = System.currentTimeMillis();		BufferedOutputStream outPutStream = null;		XSSFWorkbook workbook = null;		FileInputStream inputStream = null;		String filePath = "E:\\txt\\111.xlsx";		try {			 workbook = getWorkBook(filePath);			 XSSFSheet sheet = workbook.getSheetAt(0);			 for (int i = 0; i < 40; i++) {				 for (int z = 0; z < 1000; z++) {					 XSSFRow row = sheet.createRow(i*1000+z);					 for (int j = 0; j < 10; j++) {						 row.createCell(j).setCellValue("你好："+j);					 }				 }				 //每次要获取新的文件流对象，避免将之前写入的数据覆盖掉				 outPutStream = new BufferedOutputStream(new FileOutputStream(filePath));				 workbook.write(outPutStream);			}		} catch (IOException e) {			e.printStackTrace();		}finally {			if(outPutStream!=null) {				try {					outPutStream.close();				} catch (IOException e) {					e.printStackTrace();				}			}			if(inputStream!=null) {				try {					inputStream.close();				} catch (IOException e) {					e.printStackTrace();				}			}			if(workbook!=null) {				try {					workbook.close();				} catch (IOException e) {					e.printStackTrace();				}			}		}		long endTime = System.currentTimeMillis();		System.out.println(endTime-startTime);	}	/**	 * 先创建一个XSSFWorkbook对象	 * @param filePath	 * @return	 */	public static XSSFWorkbook getWorkBook(String filePath) {		XSSFWorkbook workbook =  null;		try {			File fileXlsxPath = new File(filePath);			BufferedOutputStream outPutStream = new BufferedOutputStream(new FileOutputStream(fileXlsxPath));			workbook = new XSSFWorkbook();			workbook.createSheet("测试");			workbook.write(outPutStream);		} catch (Exception e) {			e.printStackTrace();		}		return workbook;	}	}

2：这种方式效率高一些，属于一次性写入，数据量越大越明显，4万条数据要17秒左右

package com.test;import java.io.BufferedOutputStream;import java.io.File;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;import org.apache.poi.openxml4j.exceptions.InvalidFormatException;import org.apache.poi.xssf.usermodel.XSSFRow;import org.apache.poi.xssf.usermodel.XSSFSheet;import org.apache.poi.xssf.usermodel.XSSFWorkbook;public class POIController {	/**	 * 这种方式效率高一些，属于一次性写入，数据量越大越明显，4万条数据要17秒左右	 * @param args	 * @throws FileNotFoundException	 * @throws InvalidFormatException	 */	public static void main(String[] args) throws FileNotFoundException, InvalidFormatException {		long startTime = System.currentTimeMillis();		BufferedOutputStream outPutStream = null;		XSSFWorkbook workbook = null;		FileInputStream inputStream = null;		String filePath = "E:\\txt\\111.xlsx";		try {			 workbook = getWorkBook(filePath);			 XSSFSheet sheet = workbook.getSheetAt(0);			 for (int i = 0; i < 40; i++) {				 for (int z = 0; z < 1000; z++) {					 XSSFRow row = sheet.createRow(i*1000+z);					 for (int j = 0; j < 10; j++) {						 row.createCell(j).setCellValue("你好："+j);					 }				 }			}			 //每次要获取新的文件流对象，避免将之前写入的数据覆盖掉			 outPutStream = new BufferedOutputStream(new FileOutputStream(filePath));			 workbook.write(outPutStream);		} catch (IOException e) {			e.printStackTrace();		}finally {			if(outPutStream!=null) {				try {					outPutStream.close();				} catch (IOException e) {					e.printStackTrace();				}			}			if(inputStream!=null) {				try {					inputStream.close();				} catch (IOException e) {					e.printStackTrace();				}			}			if(workbook!=null) {				try {					workbook.close();				} catch (IOException e) {					e.printStackTrace();				}			}		}		long endTime = System.currentTimeMillis();		System.out.println(endTime-startTime);	}	/**	 * 先创建一个XSSFWorkbook对象	 * @param filePath	 * @return	 */	public static XSSFWorkbook getWorkBook(String filePath) {		XSSFWorkbook workbook =  null;		try {			File fileXlsxPath = new File(filePath);			BufferedOutputStream outPutStream = new BufferedOutputStream(new FileOutputStream(fileXlsxPath));			workbook = new XSSFWorkbook();			workbook.createSheet("测试");			workbook.write(outPutStream);		} catch (Exception e) {			e.printStackTrace();		}		return workbook;	}	}

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