本文不建议阅读。作者已有更好的解决方案:戳这里

前言

最近做公司项目，用到了POI实现Excel导入导出的功能。
整个功能做下来，发现很多大牛的文章都已经过时，会报类似The method setBorderBottom(short) from the type HSSFCellStyle is deprecated的警告，直接使用@SupressWarnings忽略警告显然是不负责任的。因此我直接去翻了Apache POI的官方文档，使用了目前官方推荐的新实现方法。
顺便发出来，方便没有翻阅英文官方文档习惯的大家。
过两天发实现导入Excel的示例文章。

项目结构简介

• Student.java:学生实体。
• StudentService.java:业务类。
• StudentController.java: web层。
  （具体每一步的介绍在代码中都有详细的解释，此处不再赘述。如果疑惑的地方欢迎留言讨论。）

Excel导出代码展示

Student.java

@Entity
@NoArgsConstructor
@Getter
@Setter
public class Student implements Serializable{

    /** 
     * @fields serialVersionUID 
     */ 
    
    private static final long serialVersionUID = 1L;
    @Id
    @GeneratedValue(generator = "idGenerator")
    @GenericGenerator(name = "idGenerator", strategy = "uuid")
    private String id;
    private String sName;
}

StudentService.java(仅贴出实现导出功能的方法)

public void exportExcel(String[] ids, OutputStream out) {
        // 根据传入的id将要导出的Student对象放入集合中
        List<Student> list = new ArrayList<>();
        for (int i = 0; i < ids.length; i++) {
            Student student = repository.findOne(ids[i]);
            
            list.add(student);
        }

        // 设置excel表头数据
        String[] headers = { "学生ID", "学生姓名"};
        // 创建excel工作薄
        HSSFWorkbook workbook = new HSSFWorkbook();
        // 创建sheet
        HSSFSheet sheet = workbook.createSheet("数据导出");
        // 设置默认列宽为15
        sheet.setDefaultColumnWidth(15);
        // 合并标题栏单元格
        sheet.addMergedRegion(new CellRangeAddress(0, 0, 0, headers.length - 1));
        // 定义标题栏样式
        HSSFCellStyle style = workbook.createCellStyle();
        style.setFillForegroundColor(HSSFColorPredefined.SKY_BLUE.getIndex());
        style.setFillPattern(FillPatternType.SOLID_FOREGROUND);
        style.setBorderBottom(BorderStyle.THIN);
        style.setBorderLeft(BorderStyle.THIN);
        style.setBorderRight(BorderStyle.THIN);
        style.setBorderTop(BorderStyle.THIN);
        style.setAlignment(HorizontalAlignment.CENTER);
        style.setVerticalAlignment(VerticalAlignment.CENTER);
        HSSFFont font = workbook.createFont(); 
        font.setColor(HSSFColorPredefined.VIOLET.getIndex());
        font.setFontHeightInPoints((short) 18);
        style.setFont(font);
        // 定义表头样式
        HSSFCellStyle style2 = workbook.createCellStyle();
        style2.setFillForegroundColor(HSSFColorPredefined.GREEN.getIndex());
        style2.setFillPattern(FillPatternType.SOLID_FOREGROUND);
        style2.setBorderBottom(BorderStyle.THIN);
        style2.setBorderLeft(BorderStyle.THIN);
        style2.setBorderRight(BorderStyle.THIN);
        style2.setBorderTop(BorderStyle.THIN);
        style2.setAlignment(HorizontalAlignment.CENTER);
        style2.setVerticalAlignment(VerticalAlignment.CENTER);
        HSSFFont font2 = workbook.createFont();
        font2.setFontHeightInPoints((short) 12);
        style2.setFont(font2);
        // 定义数据行样式
        HSSFCellStyle style3 = workbook.createCellStyle();
        style3.setFillForegroundColor(HSSFColorPredefined.LIGHT_YELLOW.getIndex());
        style3.setFillPattern(FillPatternType.SOLID_FOREGROUND);
        style3.setBorderBottom(BorderStyle.THIN);
        style3.setBorderLeft(BorderStyle.THIN);
        style3.setBorderRight(BorderStyle.THIN);
        style3.setBorderTop(BorderStyle.THIN);
        style3.setAlignment(HorizontalAlignment.CENTER);
        style3.setVerticalAlignment(VerticalAlignment.CENTER);
        // 创建行、单元格对象
        HSSFRow row = null;
        HSSFCell cell = null;
        // 写入标题行
        row = sheet.createRow(0);
        row.setHeightInPoints(25);
        cell = row.createCell(0);
        cell.setCellStyle(style);

        HSSFRichTextString textTitle = new HSSFRichTextString("数据导出");
        cell.setCellValue(textTitle);
        // 写入表头
        row = sheet.createRow(1);
        row.setHeightInPoints(17);
        for (int i = 0; i < headers.length; i++) {
            cell = row.createCell(i);
            cell.setCellStyle(style2);
            HSSFRichTextString text = new HSSFRichTextString(headers[i]);
            cell.setCellValue(text);
        }

        // 写入数据行
        Iterator<Student> it = list.iterator();
        int index = 2;
        while (it.hasNext()) {
            row = sheet.createRow(index++);
            Student student = (Student) it.next();
            cell = row.createCell(0);
            cell.setCellStyle(style3);
            cell.setCellValue(student.getId());
            cell = row.createCell(1);
            cell.setCellStyle(style3);
            cell.setCellValue(student.getSName());
            
        }
        // 获取输出流写文件。
        try {
            workbook.write(out);    
            out.flush();
            workbook.close();
            out.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
        
    }

StudentController.java(仅贴出实现导出功能的方法)

    @RequestMapping(value = "/student/export" , method = RequestMethod.GET)
    public void exporMemberFormExcel(@RequestParam(value = "ids", defaultValue = "", required = false) String[] ids, HttpServletResponse res) throws IOException {
        logger.info("---------------导出列表到Excel--------------------");
        res.setContentType("application/msexcel;charset=UTF-8");
        res.addHeader("Content-Disposition", "attachment;filename=members.xls");
        OutputStream out = res.getOutputStream();
        studentService.exportExcel(ids, out);       
    }