poi入门之读写excel

Apache POI 是用Java编写的免费开源的跨平台的 Java API，Apache POI提供API给Java程式对Microsoft Office格式档案读和写的功能。该篇是介绍poi基本的读写数据功能。

本文操作的是xls格式的Excel，使用的jar包是：

<dependency>
	<groupId>org.apache.poi</groupId>
	<artifactId>poi</artifactId>
	<version>3.16</version>
</dependency>

如果操作的是xlsx格式的Excel，引入该jar包：

<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi-ooxml</artifactId>
    <version>xxx</version>
</dependency>

• 数据写入Excel

package com.originexcel;

import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.xssf.usermodel.XSSFRow;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;

/**
 * Created by dell on 2017/9/29.
 */
public class CreateSheet {

    public static void main(String[] args) throws IOException {

        /**
         * 思路:
         * 1、创建工作簿
         * 2、创建sheet页(可设置sheet页名)
         * 3、创建行
         * 4、取数据：先取集合，再取对象，再取属性，并将数据写入到工作簿
         * 5、创建文件，将工作簿写入文件
         */
        XSSFWorkbook workbook = new XSSFWorkbook();  // 创建工作簿
        XSSFSheet sheet = workbook.createSheet("mysheet");// sheet页名称
        XSSFRow row ;  // 行
        Map<String,Object[]> object = new TreeMap<>();

        object.put("1",new Object[]{"name","age","sex"});
        object.put("2",new Object[]{"admin01","15","女"});
        object.put("3",new Object[]{"admin02","15","女"});
        object.put("4",new Object[]{"admin03","15","女"});
        object.put("5",new Object[]{"admin04","15","女"});
        object.put("6",new Object[]{"admin05","15","女"});

        Set<String> keys = object.keySet();
        int rowid = 0;
        for (String key:keys) {
            row = sheet.createRow(rowid++);
            Object[] objects = object.get(key);
            int cellid = 0;
            for (Object obj : objects) {
                Cell cell = row.createCell(cellid++);  // 单元格
                cell.setCellValue((String)obj);
            }

        }

        FileOutputStream outputStream = new FileOutputStream(new File("test.xls"));
        workbook.write(outputStream);
        outputStream.close();
        System.out.println("test.xlsx written successfully");

    }
}

输出的效果是：

• 读取excel数据

package com.originexcel;

import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.xssf.usermodel.XSSFRow;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

import java.io.FileInputStream;
import java.io.IOException;
import java.util.Iterator;

/**
 * 读取excel的数据
 *
 * Created by dell on 2017/9/29.
 */
public class ReadWorkBook {
    static XSSFRow row;
    public static void main(String[] args) throws IOException {
        FileInputStream inputStream = new FileInputStream("test.xls");

        XSSFWorkbook workbook = new XSSFWorkbook(inputStream);

        XSSFSheet sheet = workbook.getSheetAt(0);

        Iterator<Row> rows = sheet.iterator();

        while (rows.hasNext()){
            row = (XSSFRow) rows.next();
            Iterator <Cell> cellIterator = row.cellIterator();

            Cell cell = cellIterator.next();
            switch (cell.getCellType()){
                case Cell.CELL_TYPE_NUMERIC:
                    System.out.print(cell.getNumericCellValue() + " \t\t " );
                    break;
                case Cell.CELL_TYPE_STRING:
                    System.out.print(cell.getStringCellValue() + " \t\t " );
                    break;
            }

            System.out.println();
        }
        inputStream.close();
    }

}

本文只是作为poi一个入门的demo（也是博主的处女作）。欢迎大家多多指教。