使用java进行excel读取和写入

1：添加处理excel的依赖jar包

        <!-- 引入poi，解析workbook视图 -->
        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi</artifactId>
            <version>3.16</version>
        </dependency>
        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi-ooxml</artifactId>
            <version>3.14</version>
        </dependency>
        <!-- 处理excel和上面功能是一样的-->
        <dependency>
            <groupId>net.sourceforge.jexcelapi</groupId>
            <artifactId>jxl</artifactId>
            <version>2.6.10</version>
        </dependency>

2：向excel中写入内容的类

　　WriteExcel.java

package com.li.controller;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

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;

public class WriteExcel {
    private static final String EXCEL_XLS = "xls";
    private static final String EXCEL_XLSX = "xlsx";
    
    public static void main(String[] args) {
        
        Map<String, String> dataMap=new HashMap<String, String>();
        dataMap.put("BankName", "BankName");
        dataMap.put("Addr", "Addr");
        dataMap.put("Phone", "Phone");
        List<Map> list=new ArrayList<Map>();
        list.add(dataMap);
        writeExcel(list, 3, "D:/writeExcel.xlsx");
        
    }

    public static void writeExcel(List<Map> dataList, int cloumnCount,String finalXlsxPath){
        OutputStream out = null;
        try {
            // 获取总列数
            int columnNumCount = cloumnCount;
            // 读取Excel文档
            File finalXlsxFile = new File(finalXlsxPath);
            Workbook workBook = getWorkbok(finalXlsxFile);
            // sheet 对应一个工作页
            Sheet sheet = workBook.getSheetAt(0);
            /**
             * 删除原有数据，除了属性列
             */
            int rowNumber = sheet.getLastRowNum();    // 第一行从0开始算
            System.out.println("原始数据总行数，除属性列：" + rowNumber);
            for (int i = 1; i <= rowNumber; i++) {
                Row row = sheet.getRow(i);
                sheet.removeRow(row);
            }
            // 创建文件输出流，输出电子表格：这个必须有，否则你在sheet上做的任何操作都不会有效
            out =  new FileOutputStream(finalXlsxPath);
            workBook.write(out);
            /**
             * 往Excel中写新数据
             */
            for (int j = 0; j < dataList.size(); j++) {
                // 创建一行：从第二行开始，跳过属性列
                Row row = sheet.createRow(j + 1);
                // 得到要插入的每一条记录
                Map dataMap = dataList.get(j);
                String name = dataMap.get("BankName").toString();
                String address = dataMap.get("Addr").toString();
                String phone = dataMap.get("Phone").toString();
                for (int k = 0; k <= columnNumCount; k++) {
                // 在一行内循环
                Cell first = row.createCell(0);
                first.setCellValue(name);
        
                Cell second = row.createCell(1);
                second.setCellValue(address);
        
                Cell third = row.createCell(2);
                third.setCellValue(phone);
                }
            }
            // 创建文件输出流，准备输出电子表格：这个必须有，否则你在sheet上做的任何操作都不会有效
            out =  new FileOutputStream(finalXlsxPath);
            workBook.write(out);
        } catch (Exception e) {
            e.printStackTrace();
        } finally{
            try {
                if(out != null){
                    out.flush();
                    out.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        System.out.println("数据导出成功");
    }

    /**
     * 判断Excel的版本,获取Workbook
     * @param in
     * @param filename
     * @return
     * @throws IOException
     */
    public static Workbook getWorkbok(File file) throws IOException{
        Workbook wb = null;
        FileInputStream in = new FileInputStream(file);
        if(file.getName().endsWith(EXCEL_XLS)){     //Excel&nbsp;2003
            wb = new HSSFWorkbook(in);
        }else if(file.getName().endsWith(EXCEL_XLSX)){    // Excel 2007/2010
            wb = new XSSFWorkbook(in);
        }
        return wb;
    }
}

3:读取Excel中的数据，并写入list中

package com.li.controller;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

import jxl.Sheet;
import jxl.Workbook;
import jxl.read.biff.BiffException;
public class ReadExcel {
    public static void main(String[] args) {
        ReadExcel obj = new ReadExcel();
        // 此处为我创建Excel路径：E:/zhanhj/studysrc/jxl下
        File file = new File("D:/readExcel.xls");
        List excelList = obj.readExcel(file);
        System.out.println("list中的数据打印出来");
        for (int i = 0; i < excelList.size(); i++) {
            List list = (List) excelList.get(i);
            for (int j = 0; j < list.size(); j++) {
                System.out.print(list.get(j));
            }
            System.out.println();
        }

    }
    // 去读Excel的方法readExcel，该方法的入口参数为一个File对象
    public List readExcel(File file) {
        try {
            // 创建输入流，读取Excel
            InputStream is = new FileInputStream(file.getAbsolutePath());
            // jxl提供的Workbook类
            Workbook wb = Workbook.getWorkbook(is);
            // Excel的页签数量
            int sheet_size = wb.getNumberOfSheets();
            for (int index = 0; index < sheet_size; index++) {
                List<List> outerList=new ArrayList<List>();
                // 每个页签创建一个Sheet对象
                Sheet sheet = wb.getSheet(index);
                // sheet.getRows()返回该页的总行数
                for (int i = 0; i < sheet.getRows(); i++) {
                    List innerList=new ArrayList();
                    // sheet.getColumns()返回该页的总列数
                    for (int j = 0; j < sheet.getColumns(); j++) {
                        String cellinfo = sheet.getCell(j, i).getContents();
                        if(cellinfo.isEmpty()){
                            continue;
                        }
                        innerList.add(cellinfo);
                        System.out.print(cellinfo);
                    }
                    outerList.add(i, innerList);
                    System.out.println();
                }
                return outerList;
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (BiffException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }
}

4：在D盘下面创建readExcel.xls（有内容） 和writeExcel.xlsx即可