POI dealing with Excel learning

POI Study

​ Import dependencies first

<dependencies>
        <!--xls(03)-->
    <dependency>
        <groupId>org.apache.poi</groupId>
        <artifactId>poi</artifactId>
        <version>3.9</version>
    </dependency>

    <!--xlsx(07)-->
    <dependency>
        <groupId>org.apache.poi</groupId>
        <artifactId>poi-ooxml</artifactId>
        <version>3.9</version>
    </dependency>
    <!-- Date formatting tool -->
    <dependency>
        <groupId>joda-time</groupId>
        <artifactId>joda-time</artifactId>
        <version>2.10.1</version>
    </dependency>
    <!--test-->
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.12</version>
    </dependency>
</dependencies>

Excel2003 The version can only be put at most 65536 Row data (xls)

Excel2007 The version does not have this limitation (xlsx)

Excel form

• workbook
  • Worksheet
    • That's ok
    • Column
      • Cell

Big files write HSSF

shortcoming ： At most, it can only deal with 65536 That's ok , Otherwise, an exception will be thrown

advantage ： Write cache in process , Do not operate disk , The last one-time write to disk , Fast

Big files write XSSF

shortcoming ： Writing data is very slow , Very memory intensive , Memory overflow can also occur , Such as 100 Ten thousand

advantage ： Can write a large amount of data , Such as 20 Ten thousand

Big files write SXSSF

advantage ： Can write a large amount of data , Such as 20 Ten thousand

operation Excel

Create a Excel 07 Version of xlsx file

package com.muyu.main;

import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.xssf.streaming.SXSSFWorkbook;
import org.joda.time.DateTime;

import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

public class ExcelWriteTest {
    
	private static String path = "E:\\code\\IDEA code\\ControlExcel\\Excel-poi";
	public static void main(String[] args) throws IOException {
    
		//1.  Create Workbook 
		Workbook workbook = new SXSSFWorkbook();
		//2.  Create a worksheet 
		Sheet sheet = workbook.createSheet(" Fan Xu practice table ");
		//3.  Create a line 
		Row row1 = sheet.createRow(0);
		//4.  Create a cell 
		Cell cell11 = row1.createCell(0);
		cell11.setCellValue(" New learning today ：");
		Cell cell12 = row1.createCell(1);
		cell12.setCellValue("poi");
		// The second line 
		Row row2 = sheet.createRow(1);
		Cell cell21 = row2.createCell(0);
		Cell cell22 = row2.createCell(1);

		String time = new DateTime().toString("yyyy-MM-dd HH:mm:ss");
		cell21.setCellValue(" Count the time ：");
		cell22.setCellValue(time);

		FileOutputStream fileOutputStream = new FileOutputStream(path + "\\FanXu.xlsx");
		workbook.write(fileOutputStream);
		fileOutputStream.close();
		
	}
}

image xls Write large amount of data in

@Test
public void xls65536Test() throws IOException {
    
    // Fast execution 
    long begain = System.currentTimeMillis();
    Workbook workbook = new HSSFWorkbook();
    Sheet sheet = workbook.createSheet("66636");
    for (int i = 0; i <65536; i++) {
    
        Row row = sheet.createRow(i);
        for (int j = 0; j <10 ; j++) {
    
            Cell cell = row.createCell(j);
            cell.setCellValue(j);
        }
    }
    FileOutputStream fileOutputStream = new FileOutputStream(path + "\\xls65536Test.xls");
    workbook.write(fileOutputStream);
    fileOutputStream.close();
    System.out.println("over");
    long end = System.currentTimeMillis();
    double time = (double)(end-begain)/1000 ;
    System.out.println(time);

}
//over  Output 
//1.776

towards xlsx Write large amount of data in

@Test
public void xlsx65536Test() throws IOException {
    
    // Slow execution  1 Ten thousand have been implemented 2.682 second 
    long begain = System.currentTimeMillis();
    Workbook workbook = new XSSFWorkbook();
    Sheet sheet = workbook.createSheet("66636");
    for (int i = 0; i <10000; i++) {
    
        Row row = sheet.createRow(i);
        for (int j = 0; j <10 ; j++) {
    
            Cell cell = row.createCell(j);
            cell.setCellValue(j);
        }
    }
    FileOutputStream fileOutputStream = new FileOutputStream(path + "\\xlsx65536Test.xlsx");
    workbook.write(fileOutputStream);
    fileOutputStream.close();
    System.out.println("over");
    long end = System.currentTimeMillis();
    double time = (double)(end-begain)/1000 ;
    System.out.println(time);

}
//over  Output 
//2.682

Optimize ！ The second method is to xlsx Write large amount of data in

@Test
public void sxlsx65536Test() throws IOException {
    
    //20 Ten thousand have been implemented 4.205 second 
    long begain = System.currentTimeMillis();
    Workbook workbook = new SXSSFWorkbook();
    Sheet sheet = workbook.createSheet("66636");
    for (int i = 0; i <200000; i++) {
    
        Row row = sheet.createRow(i);
        for (int j = 0; j <10 ; j++) {
    
            Cell cell = row.createCell(j);
            cell.setCellValue(j);
        }
    }
    FileOutputStream fileOutputStream = new FileOutputStream(path + "\\xlsx65536Test.xlsx");
    workbook.write(fileOutputStream);
    fileOutputStream.close();
    ((SXSSFWorkbook)workbook).dispose();
    System.out.println("over");
    long end = System.currentTimeMillis();
    double time = (double)(end-begain)/1000 ;
    System.out.println(time);

}
//over  Output 
//4.205

read Excel The operation of

package com.muyu.main;

import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.xssf.streaming.SXSSFWorkbook;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import org.joda.time.DateTime;
import org.junit.Test;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

public class ExcelReadTest {
    
	private static String path = "E:\\code\\IDEA code\\ControlExcel\\Excel-poi";

	@Test
	public void getExcelValue() throws IOException {
    
		FileInputStream fileInputStream = new FileInputStream("FanXu.xlsx");
		Workbook workbook = new XSSFWorkbook(fileInputStream);
		Sheet sheet = workbook.getSheet(" Fan Xu practice table ");
		Row row = sheet.getRow(0);
		Cell cell = row.getCell(1);
		System.out.println(cell.getStringCellValue());
		fileInputStream.close();
	}
}