Java中使用POI导入导出工具类

依赖：

<dependency>
			<groupId>org.apache.poi</groupId>
			<artifactId>poi</artifactId>
			<version>3.17</version>
		</dependency>
		<dependency>
			<groupId>org.apache.poi</groupId>
			<artifactId>poi-ooxml</artifactId>
			<version>3.17</version>
		</dependency>

数据：

class Person {
    private String name;
    private String sex;
    private Integer age;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }


    @Override
    public String toString() {
        return "Person{" +
                "name='" + name + '\'' +
                ", sex='" + sex + '\'' +
                ", age=" + age +
                '}';
    }
}

 @RequestMapping("export")
    public void exportExcel(HttpServletRequest request, HttpServletResponse response) throws NoSuchMethodException, IOException, InvocationTargetException, IllegalAccessException {
        String filename = "人员信息";

        String[] columNames = {"name", "sex", "age"};
        Person p1 = new Person();
        p1.setName("张三");
        p1.setSex("男");
        p1.setAge(20);
        Person p2 = new Person();
        p2.setName("李四");
        p2.setSex("女");
        p2.setAge(22);

        List<Person> dataList = new ArrayList<>();
        dataList.add(p1);
        dataList.add(p2);

        exportExcel(request, response, filename, columNames, dataList);
    }

导出工具类：

/**
     * 
     * @param request 请求
     * @param response 响应
     * @param filename 文件名
     * @param headers 标题头
     * @param headerFields 标题字段
     * @param rowDatas 数据集合
     * @throws IOException
     * @throws NoSuchMethodException
     * @throws SecurityException
     * @throws IllegalAccessException
     * @throws IllegalArgumentException
     * @throws InvocationTargetException
     */
    public static void exportExcel(HttpServletRequest request, HttpServletResponse response, String filename,String[] headers, String[] headerFields, Collection<?> rowDatas) throws IOException, NoSuchMethodException, SecurityException, IllegalAccessException, IllegalArgumentException, InvocationTargetException {
        response.setHeader("Connection", "close");
        response.setHeader("Content-Type", "application/vnd.ms-excel;charset=UTF-8");
        filename = filename + System.currentTimeMillis() + ".xls";
        filename = encodeFileName(request, filename);
        response.setHeader("Content-Disposition", "attachment;filename=" + filename);

        // 第一步，创建一个webbook，对应一个Excel文件
        HSSFWorkbook wb = new HSSFWorkbook();
        // 第二步，在webbook中添加一个sheet,对应Excel文件中的sheet
        HSSFSheet sheet = wb.createSheet("sheet1");
        sheet.setDefaultRowHeightInPoints(13);//设置缺省列高
        sheet.setDefaultColumnWidth(15);//设置缺省列宽

        // 第三步，在sheet中添加表头第0行,注意老版本poi对Excel的行数列数有限制short
        HSSFRow row = sheet.createRow(0);
        // 第四步，创建单元格，并设置值表头 设置表头居中
        HSSFCellStyle style = wb.createCellStyle();
        //style.setAlignment(HSSFCellStyle.ALIGN_CENTER); // 创建一个居中格式 HSSFCellStyle.ALIGN_CENTER 3.15poi 版本问题
        style.setAlignment(HorizontalAlignment.CENTER); // 创建一个居中格式  HorizontalAlignment.CENTER 3.17poi

        HSSFFont font = wb.createFont();
        font.setColor(Font.COLOR_NORMAL); // 将字体设置为“正常”
        font.setBold(true);//粗体显示
        font.setFontName("微软雅黑");  // 将“微软雅黑”字体应用到当前单元格上
        font.setFontHeightInPoints((short) 10); // 将字体大小设置为10px

        style.setFont(font);


        //设置单元格表头
        for (int i = 0; i < headers.length; i++) {
            HSSFCell cell = row.createCell(i);
            cell.setCellValue(headers[i]);
            cell.setCellStyle(style);
        }

        // 第五步，写入实体数据 这些数据从数据库得到
        Iterator<?> it = rowDatas.iterator();
        int  i = 0;
        while (it.hasNext()) {
            row = sheet.createRow(i + 1);
            Object object =  it.next();
            // 第四步，创建单元格，并设置值
            for (int j = 0; j < headerFields .length; j++) {
                Method method = object.getClass().getDeclaredMethod("get" + headerFields [j].substring(0, 1).toUpperCase() + headerFields [j].substring(1));
                Object value = method.invoke(object);
                row.createCell(j).setCellValue(value == null ? "" : value.toString());
            }

        }

        // 第六步，导出文件
        OutputStream out = response.getOutputStream();
        wb.write(out);
        out.flush();
        out.close();
    }


    /**
     *
     * @Title: encodeFileName
     * @Description: 导出文件转换文件名称编码
     * @param @param fileNames
     * @param @param request
     * @param @return    设定文件
     * @return String    返回类型
     * @throws
     */
    public static String encodeFileName(HttpServletRequest request,String fileNames) {
        String codedFilename = null;
        try {
            String agent = request.getHeader("USER-AGENT");
            if (null != agent && -1 != agent.indexOf("MSIE") || null != agent
                    && -1 != agent.indexOf("Trident") || null != agent && -1 != agent.indexOf("Edge")) {// ie浏览器及Edge浏览器
                String name = java.net.URLEncoder.encode(fileNames, "UTF-8");
                codedFilename = name;
            } else if (null != agent && -1 != agent.indexOf("Mozilla")) {// 火狐,Chrome等浏览器
                codedFilename = new String(fileNames.getBytes("UTF-8"), "iso-8859-1");
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return codedFilename ;
    }

导入工具类：

import org.apache.poi.ss.usermodel.*;

import java.io.File;
import java.io.FileInputStream;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.List;


public class ImportExcelUtil {
    /**
     * 读取excel文件当中的数据，将其每行数据转换成javabean，将javabean存放到List集合中并返回。
     * @param c List集合中存储的每一个元素的类型
     * @param file excel文件路径
     * @param headerFields 需要获取值的字段，传入参数列需要和你的Excel字段列对应
     * @return dataList
     * @throws Exception
     */
    public static List getDataListFromExcel(Class c, File file,String[] headerFields) throws Exception {
        List dataList = new ArrayList();
        FileInputStream inStream = new FileInputStream(file);
        Workbook workBook = WorkbookFactory.create(inStream);
        Sheet sheet = workBook.getSheetAt(0);
//        Row firstRow = sheet.getRow(0);
        //如果sheet中一行数据都没有则返回-1，只有第一行有数据则返回0，最后有数据的行是第n行则返回 n-1
        int rowNum = sheet.getLastRowNum() + 1;
        //如果不是第一行开始遍历单元格
        for (int i = 1; i < rowNum; i++) {
            Row row = sheet.getRow(i);
            Object o = c.newInstance();
            //getLastCellNum  如果row中一列数据都没有则返回-1，只有第一列有数据则返回1，最后有数据的列是第n列则返回 n
            for (int j = 0; j < row.getLastCellNum(); j++) {
                //第一行，第几个单元格,如果列对应的就是标题头，使用这种方式可以，如果不是，则需要传入列的字段
//                Cell columnCell = firstRow.getCell(j);
//                String column = getCellValue(columnCell);
//                Field field = c.getDeclaredField(column);
                Field field = c.getDeclaredField(headerFields[j]);
                //第i行，第j个单元格
                Cell cell = row.getCell(j);
                String str = getCellValue(cell);
                Method setMethod = c.getDeclaredMethod(
                        "set" + headerFields[j].substring(0, 1).toUpperCase() + headerFields[j].substring(1), field.getType());
               //判断是否是字符类型
                String reg = "^[0-9]+(.[0-9]+)?$";
                if(!str.matches(reg)){
                    setMethod.invoke(o, str);
                }else {
                    Double cellValue = Double.parseDouble(str);
                    setMethod.invoke(o, cellValue);
                }
            }
            dataList.add(o);
        }
        return dataList;
    }

    private static String getCellValue(Cell cell) {
        String cellValue = "";
        DataFormatter formatter = new DataFormatter();
        if (cell != null) {
            switch (cell.getCellTypeEnum()) {
                case NUMERIC:
                    if (DateUtil.isCellDateFormatted(cell)) {
                        cellValue = formatter.formatCellValue(cell);
                    } else {
                        double value = cell.getNumericCellValue();
                        int intValue = (int) value;
                        cellValue = value - intValue == 0 ? String.valueOf(intValue) : String.valueOf(value);
                    }
                    break;
                case STRING:
                    cellValue = cell.getStringCellValue();
                    break;
                case BOOLEAN:
                    cellValue = String.valueOf(cell.getBooleanCellValue());
                    break;
                case FORMULA: {
                    try {
                        cellValue = String.valueOf(cell.getNumericCellValue());
                    } catch (IllegalStateException e) {
                        cellValue = String.valueOf(cell.getRichStringCellValue());
                    }
                }
                break;
                case BLANK:
                    cellValue = "";
                    break;
                case ERROR:
                    cellValue = "";
                    break;
                default:
                    cellValue = cell.toString().trim();
                    break;
            }
        }
        return cellValue.trim();
    }


    public static void main(String[] args) throws Exception {
        String[] headerFields={"name","sex","age"};
        File file=new File("C:\\Users\\Administrator\\Downloads\\人员信息1563273376269.xls");
        List dataListFromExcel = getDataListFromExcel(Person.class, file, headerFields);
        System.out.println(dataListFromExcel);


    }

}