初识poi和easyExcel

1. 聊聊POI和EasyExcel

image-20211029204332167

2. Excel基本写操作

  • 导入依赖

    
    
    
        org.apache.poi
        poi
        3.10-FINAL
    

    
    
        org.apache.poi
        poi-ooxml
        3.10-FINAL
    
    
    
        junit
        junit
        4.12
    
    
    
        joda-time
        joda-time
        2.10.5

ExcelWriteTest.java

package top.gujiakai;

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.usermodel.XSSFWorkbook;
import org.joda.time.DateTime;
import org.junit.Test;

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

public class ExcelWriteTest {

    String PATH="D:\\project\\Java\\Excel\\Kai-poi";

    @Test
    public void testWrite03() throws IOException {
        //1.创建一个工作簿
        Workbook workbook = new HSSFWorkbook();
        //2.创建一个工作表
        Sheet sheet = workbook.createSheet("蔡伟粉丝统计表");
        //3.创建一个行
        Row row1 = sheet.createRow(0);
        //4.创建一个单元格
        Cell cell11 = row1.createCell(0);
        cell11.setCellValue("今日新增粉丝");
        Cell cell12 = row1.createCell(1);
        cell12.setCellValue("我爱你");

        //第二行
        Row row2 = sheet.createRow(1);
        Cell cell21 = row2.createCell(0);
        cell21.setCellValue("统计时间");

        Cell cell22 = row2.createCell(1);
        String time = new DateTime().toString("yyyy-MM-dd HH:mm:ss");
        cell22.setCellValue(time);

        //生成一张表(IOl流) 03版本就是使用xls结尾！
        FileOutputStream fileOutputStream = new FileOutputStream(PATH + "蔡伟粉丝统计03.xls");
        //输出
        workbook.write(fileOutputStream);
        //关闭流
        fileOutputStream.close();

        System.out.println("蔡伟粉丝统计表03 生成完毕！");
    }


    @Test
    public void testWrite07() throws IOException {
        //1.创建一个工作簿
        XSSFWorkbook workbook = new XSSFWorkbook();
        //2.创建一个工作表
        Sheet sheet = workbook.createSheet("蔡伟粉丝统计表");
        //3.创建一个行
        Row row1 = sheet.createRow(0);
        //4.创建一个单元格
        Cell cell11 = row1.createCell(0);
        cell11.setCellValue("今日新增粉丝");
        Cell cell12 = row1.createCell(1);
        cell12.setCellValue("我不爱你");

        //第二行
        Row row2 = sheet.createRow(1);
        Cell cell21 = row2.createCell(0);
        cell21.setCellValue("统计时间");

        Cell cell22 = row2.createCell(1);
        String time = new DateTime().toString("yyyy-MM-dd HH:mm:ss");
        cell22.setCellValue(time);

        //生成一张表(IOl流) 07版本就是使用xlsx结尾！
        FileOutputStream fileOutputStream = new FileOutputStream(PATH + "蔡伟粉丝统计07.xlsx");
        //输出
        workbook.write(fileOutputStream);
        //关闭流
        fileOutputStream.close();

        System.out.println("蔡伟粉丝统计表07 生成完毕！");
    }
}

3. 大数据量的写入

image-20211030150906946

ExcelWriteTest.java

package top.gujiakai;

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

public class ExcelWriteTest {

    String PATH="D:\\project\\Java\\Excel\\Kai-poi";

    @Test
    public void testWrite03() throws IOException {
        //1.创建一个工作簿
        Workbook workbook = new HSSFWorkbook();
        //2.创建一个工作表
        Sheet sheet = workbook.createSheet("蔡伟粉丝统计表");
        //3.创建一个行
        Row row1 = sheet.createRow(0);
        //4.创建一个单元格
        Cell cell11 = row1.createCell(0);
        cell11.setCellValue("今日新增粉丝");
        Cell cell12 = row1.createCell(1);
        cell12.setCellValue("我爱你");

        //第二行
        Row row2 = sheet.createRow(1);
        Cell cell21 = row2.createCell(0);
        cell21.setCellValue("统计时间");

        Cell cell22 = row2.createCell(1);
        String time = new DateTime().toString("yyyy-MM-dd HH:mm:ss");
        cell22.setCellValue(time);

        //生成一张表(IOl流) 03版本就是使用xls结尾！
        FileOutputStream fileOutputStream = new FileOutputStream(PATH + "蔡伟粉丝统计03.xls");
        //输出
        workbook.write(fileOutputStream);
        //关闭流
        fileOutputStream.close();

        System.out.println("蔡伟粉丝统计表03 生成完毕！");
    }


    @Test
    public void testWrite07() throws IOException {
        //1.创建一个工作簿
        XSSFWorkbook workbook = new XSSFWorkbook();
        //2.创建一个工作表
        Sheet sheet = workbook.createSheet("蔡伟粉丝统计表");
        //3.创建一个行
        Row row1 = sheet.createRow(0);
        //4.创建一个单元格
        Cell cell11 = row1.createCell(0);
        cell11.setCellValue("今日新增粉丝");
        Cell cell12 = row1.createCell(1);
        cell12.setCellValue("我不爱你");

        //第二行
        Row row2 = sheet.createRow(1);
        Cell cell21 = row2.createCell(0);
        cell21.setCellValue("统计时间");

        Cell cell22 = row2.createCell(1);
        String time = new DateTime().toString("yyyy-MM-dd HH:mm:ss");
        cell22.setCellValue(time);

        //生成一张表(IOl流) 07版本就是使用xlsx结尾！
        FileOutputStream fileOutputStream = new FileOutputStream(PATH + "蔡伟粉丝统计07.xlsx");
        //输出
        workbook.write(fileOutputStream);
        //关闭流
        fileOutputStream.close();

        System.out.println("蔡伟粉丝统计表07 生成完毕！");
    }

    @Test
    public void testWrite03BigData() throws IOException {
        //开始时间
        long begin=System.currentTimeMillis();
        //创建一个工作簿
        Workbook workbook = new HSSFWorkbook();
        //创建一个工作表
        Sheet sheet = workbook.createSheet();
        //写入数据
        for(int rowNum=0;rowNum<65536;rowNum++){
            Row row = sheet.createRow(rowNum);
            for(int cellNum=0;cellNum<10;cellNum++){
                Cell cell = row.createCell(cellNum);
                cell.setCellValue(cellNum);
            }
        }

        System.out.println("over");
        FileOutputStream fileOutputStream = new FileOutputStream(PATH + "testWrite03BigData.xls");
        workbook.write(fileOutputStream);
        fileOutputStream.close();
        //结束事件
        long end=System.currentTimeMillis();
        System.out.println((double)(end-begin)/1000);
    }

    //耗时较长，缓存
    @Test
    public void testWrite07BigData() throws IOException {
        //开始时间
        long begin=System.currentTimeMillis();
        //创建一个工作簿
        Workbook workbook = new XSSFWorkbook();
        //创建一个工作表
        Sheet sheet = workbook.createSheet();
        //写入数据
        for(int rowNum=0;rowNum<65537;rowNum++){
            Row row = sheet.createRow(rowNum);
            for(int cellNum=0;cellNum<10;cellNum++){
                Cell cell = row.createCell(cellNum);
                cell.setCellValue(cellNum);
            }
        }

        System.out.println("over");
        FileOutputStream fileOutputStream = new FileOutputStream(PATH + "testWrite07BigData.xlsx");
        workbook.write(fileOutputStream);
        fileOutputStream.close();
        //结束事件
        long end=System.currentTimeMillis();
        System.out.println((double)(end-begin)/1000);
    }


    @Test
    public void testWrite07BigDataS() throws IOException {
        //开始时间
        long begin=System.currentTimeMillis();
        //创建一个工作簿
        Workbook workbook = new SXSSFWorkbook();
        //创建一个工作表
        Sheet sheet = workbook.createSheet();
        //写入数据
        for(int rowNum=0;rowNum<65537;rowNum++){
            Row row = sheet.createRow(rowNum);
            for(int cellNum=0;cellNum<10;cellNum++){
                Cell cell = row.createCell(cellNum);
                cell.setCellValue(cellNum);
            }
        }

        System.out.println("over");
        FileOutputStream fileOutputStream = new FileOutputStream(PATH + "testWrite07BigDataS.xlsx");
        workbook.write(fileOutputStream);
        fileOutputStream.close();
        //清除临时文件
        ((SXSSFWorkbook) workbook).dispose();
        //结束事件
        long end=System.currentTimeMillis();
        System.out.println((double)(end-begin)/1000);
    }
}

4. Excel基本读取及注意

ExcelReadTest.java

package top.gujiakai;

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.usermodel.XSSFWorkbook;
import org.junit.Test;

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

public class ExcelReadTest{
    String PATH="D:\\project\\Java\\Excel\\";

    @Test
    public void testRead03() throws IOException {
        //1.获取文件流
        FileInputStream fileInputStream = new FileInputStream(PATH + "Kai-poi蔡伟粉丝统计03.xls");
        //2.获取工作簿
        Workbook workbook = new HSSFWorkbook(fileInputStream);
        //3.获取表
        Sheet sheet = workbook.getSheetAt(0);
        //4.得到行
        Row row = sheet.getRow(0);
        //5.得到列
        Cell cell = row.getCell(1);

        //读取值的时候，要注意类型！
        System.out.println(cell.getStringCellValue());
        fileInputStream.close();
    }

    @Test
    public void testRead07() throws IOException {
        //1.获取文件流
        FileInputStream fileInputStream = new FileInputStream(PATH + "Kai-poi蔡伟粉丝统计07.xlsx");
        //2.获取工作簿
        Workbook workbook = new XSSFWorkbook(fileInputStream);
        //3.获取表
        Sheet sheet = workbook.getSheetAt(0);
        //4.得到行
        Row row = sheet.getRow(0);
        //5.得到列
        Cell cell = row.getCell(1);

        //读取值的时候，要注意类型！
        System.out.println(cell.getStringCellValue());
        fileInputStream.close();

    }

}

5. 难点-读取不同类型的数据

ExcelReadTest.java

package top.gujiakai;

import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.*;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import org.junit.Test;

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

public class ExcelReadTest {
    String PATH = "D:\\project\\Java\\Excel\\";

    @Test
    public void testRead03() throws IOException {
        //1.获取文件流
        FileInputStream fileInputStream = new FileInputStream(PATH + "Kai-poi蔡伟粉丝统计03.xls");
        //2.获取工作簿
        Workbook workbook = new HSSFWorkbook(fileInputStream);
        //3.获取表
        Sheet sheet = workbook.getSheetAt(0);
        //4.得到行
        Row row = sheet.getRow(0);
        //5.得到列
        Cell cell = row.getCell(1);

        //读取值的时候，要注意类型！
        System.out.println(cell.getStringCellValue());
        fileInputStream.close();
    }

    @Test
    public void testRead07() throws IOException {
        //1.获取文件流
        FileInputStream fileInputStream = new FileInputStream(PATH + "Kai-poi蔡伟粉丝统计07.xlsx");
        //2.获取工作簿
        Workbook workbook = new XSSFWorkbook(fileInputStream);
        //3.获取表
        Sheet sheet = workbook.getSheetAt(0);
        //4.得到行
        Row row = sheet.getRow(0);
        //5.得到列
        Cell cell = row.getCell(1);

        //读取值的时候，要注意类型！
        System.out.println(cell.getStringCellValue());
        fileInputStream.close();

    }


    @Test
    public void testCellType() throws IOException {
        //获取文件流
        FileInputStream fileInputStream = new FileInputStream(PATH + "明细表.xls");
        //获取一个工作簿
        Workbook workbook = new HSSFWorkbook(fileInputStream);
        Sheet sheet = workbook.getSheetAt(0);
        //获取标题内容
        Row rowTitle = sheet.getRow(0);
        if (rowTitle != null) {
            int cellCount = rowTitle.getPhysicalNumberOfCells();
            for (int cellNum = 0; cellNum < cellCount; cellNum++) {
                Cell cell = rowTitle.getCell(cellNum);
                if (cell != null) {
                    CellType cellType = cell.getCellType();
                    String cellValue = cell.getStringCellValue();
                    System.out.print(cellValue + " | ");
                }
            }
            System.out.println();
        }

        //...读取值的时候，一定要注意类型。
    }
}

6. 了解-计算公式

@Test
public void testFormula() throws IOException {
    FileInputStream fileInputStream = new FileInputStream(PATH + "公式.xlsx");
    Workbook workbook = new XSSFWorkbook(fileInputStream);
    Sheet sheet = workbook.getSheetAt(0);

    Row row = sheet.getRow(4);
    Cell cell = row.getCell(0);

    //拿到计算公式
    XSSFFormulaEvaluator FormulaEvaluator = new XSSFFormulaEvaluator((XSSFWorkbook) workbook);

    //输出单元格的内容
    CellType cellType = cell.getCellType();
    //        switch(cellType){
    //            case Cell.CELL_:
    //        }
    String cellFormula = cell.getCellFormula();
    System.out.println(cellFormula);

    //计算
    CellValue evaluate = FormulaEvaluator.evaluate(cell);
    String s = evaluate.formatAsString();
    System.out.println(s);
}

7. EasyExcel使用

  • 导入依赖

    com.alibaba
    easyexcel
    3.0.1

image-20211030184626897

DemoData.java

package easy;

import com.alibaba.excel.annotation.ExcelIgnore;
import com.alibaba.excel.annotation.ExcelProperty;
import lombok.Data;

import java.util.Date;

@Data
public class DemoData {
    @ExcelProperty("字符串标题")
    private String string;
    @ExcelProperty("日期标题")
    private Date date;
    @ExcelProperty("数字标题")
    private Double doubleData;
    /**
     * 忽略这个字段
     */
    @ExcelIgnore
    private String ignore;
}

EasyTest.java

package easy;

import com.alibaba.excel.EasyExcel;
import org.junit.Test;

import java.util.ArrayList;
import java.util.Date;
import java.util.List;

public class EasyTest {
    String PATH="D:\\project\\Java\\Excel\\Kai-poi";

    private List data() {
        List list = new ArrayList();
        for (int i = 0; i < 10; i++) {
            DemoData data = new DemoData();
            data.setString("字符串" + i);
            data.setDate(new Date());
            data.setDoubleData(0.56);
            list.add(data);
        }
        return list;
    }

//根据list，写入Excel。
@Test
public void simpleWrite() {
    String fileName = PATH+"EasyTest.xlsx";
    // 这里 需要指定写用哪个class去读，然后写到第一个sheet，名字为模板 然后文件流会自动关闭
    // 如果这里想使用03 则 传入excelType参数即可
    //write(fileName,格式类)
    //sheet(声明)
    //doWrite(数据)
    EasyExcel.write(fileName, DemoData.class).sheet("模板").doWrite(data());
}

    /**
     * 最简单的读
     * 
1. 创建excel对应的实体对象 参照{@link DemoData}
     * 
2. 由于默认一行行的读取excel，所以需要创建excel一行一行的回调监听器，参照{@link DemoDataListener}
     * 
3. 直接读即可
     */
    @Test
    public void simpleRead() {
        String fileName = PATH+"EasyTest.xlsx";
        // 这里 需要指定读用哪个class去读，然后读取第一个sheet 文件流会自动关闭
        EasyExcel.read(fileName, DemoData.class, new DemoDataListener()).sheet().doRead();
    }

}

DemoDAO.java

package easy;

import java.util.List;

/**
 * 假设这个是你的DAO存储。当然还要这个类让spring管理，当然你不用需要存储，也不需要这个类。
 **/
public class DemoDAO {
    public void save(List list) {
        //持久化操作
        // 如果是mybatis,尽量别直接调用多次insert,自己写一个mapper里面新增一个方法batchInsert,所有数据一次性插入
    }
}

DemoDataListener.java

package easy;

import com.alibaba.excel.context.AnalysisContext;
import com.alibaba.excel.event.AnalysisEventListener;
import com.alibaba.fastjson.JSON;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.ArrayList;
import java.util.List;

// 有个很重要的点 DemoDataListener 不能被spring管理，要每次读取excel都要new,然后里面用到spring可以构造方法传进去
public class DemoDataListener extends AnalysisEventListener {
    private static final Logger LOGGER = LoggerFactory.getLogger(DemoDataListener.class);
    /**
     * 每隔5条存储数据库，实际使用中可以3000条，然后清理list ，方便内存回收
     */
    private static final int BATCH_COUNT = 3000;
    /**
     * 缓存的数据
     */
    private List list = new ArrayList<>(BATCH_COUNT);
    /**
     * 假设这个是一个DAO，当然有业务逻辑这个也可以是一个service。当然如果不用存储这个对象没用。
     */
    private DemoDAO demoDAO;

    public DemoDataListener() {
        // 这里是demo，所以随便new一个。实际使用如果到了spring,请使用下面的有参构造函数
        demoDAO = new DemoDAO();
    }

    /**
     * 如果使用了spring,请使用这个构造方法。每次创建Listener的时候需要把spring管理的类传进来
     *
     * @param demoDAO
     */
    public DemoDataListener(DemoDAO demoDAO) {
        this.demoDAO = demoDAO;
    }

    /**
     * 这个每一条数据解析都会来调用
     *
     * @param data    one row value. Is is same as {@link AnalysisContext#readRowHolder()}
     * @param context
     */
    //读取数据会执行invoke方法
    //DemoData类型
    //AnalysisContext分析器
    @Override
    public void invoke(DemoData data, AnalysisContext context) {
        LOGGER.info("解析到一条数据:{}", JSON.toJSONString(data));
        System.out.println(JSON.toJSONString(data));
        list.add(data);
        // 达到BATCH_COUNT了，需要去存储一次数据库，防止数据几万条数据在内存，容易OOM
        if (list.size() >= BATCH_COUNT) {
            saveData();
            // 存储完成清理 list
            list = new ArrayList<>(BATCH_COUNT);
        }
    }

    /**
     * 所有数据解析完成了 都会来调用
     *
     * @param context
     */
    @Override
    public void doAfterAllAnalysed(AnalysisContext context) {
        // 这里也要保存数据，确保最后遗留的数据也存储到数据库
        saveData();
        LOGGER.info("所有数据解析完成！");
    }

    /**
     * 加上存储数据库
     */
    private void saveData() {
        LOGGER.info("{}条数据，开始存储数据库！", list.size());
        demoDAO.save(list);
        LOGGER.info("存储数据库成功！");
    }
}
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