Java WorkBook对Excel的基本操作方法

<dependency>
     <groupId>org.apache.poi</groupId>
     <artifactId>poi</artifactId>
     <version>3.9</version>
</dependency>
<dependency>
     <groupId>org.apache.poi</groupId>
     <artifactId>poi-ooxml</artifactId>
     <version>3.9</version>
</dependency>

//上传Excel
@RequestMapping("/uploadExcel")
public boolean uploadExcel(@RequestParam MultipartFile file,httpservletRequest request) throws IOException {
    if(!file.isEmpty()){
        String filePath = file.getOriginalFilename();
        //windows
        String savePath = request.getSession().getServletContext().getRealPath(filePath);
        //linux
        //String savePath = "/home/odcuser/WEBapps/file";
        File targetFile = new File(savePath);
        if(!targetFile.exists()){
            targetFile.mkdirs();
        }
 
        file.transferTo(targetFile);
        return true;
    }
    return false;
}

public static void readExcel() throws Exception{
	InputStream is = new FileInputStream(new File(fileName));
	Workbook hssfWorkbook = null;
	if (fileName.endsWith("xlsx")){
		hssfWorkbook = new XSSFWorkbook(is);//Excel 2007
	}else if (fileName.endsWith("xls")){
		hssfWorkbook = new HSSFWorkbook(is);//Excel 2003
	}
	// HSSFWorkbook hssfWorkbook = new HSSFWorkbook(is);
	// XSSFWorkbook hssfWorkbook = new XSSFWorkbook(is);
	User student = null;
	List<User> list = new ArrayList<User>();
	// 循环工作表Sheet
	for (int numSheet = 0; numSheet <hssfWorkbook.getNumberOfSheets(); numSheet++) {
		//HSSFSheet hssfSheet = hssfWorkbook.getSheetAt(numSheet);
		Sheet hssfSheet = hssfWorkbook.getSheetAt(numSheet);
		if (hssfSheet == null) {
			continue;
		}
		// 循环行Row
		for (int rowNum = 1; rowNum <= hssfSheet.getLastRowNum(); rowNum++) {
			//HSSFRow hssfRow = hssfSheet.getRow(rowNum);
			Row hssfRow = hssfSheet.getRow(rowNum);
			if (hssfRow != null) {
				student = new User();
				//HSSFCell name = hssfRow.getCell(0);
				//HSSFCell pwd = hssfRow.getCell(1);
				Cell name = hssfRow.getCell(0);
				Cell pwd = hssfRow.getCell(1);
				//这里是自己的逻辑
				student.setUserName(name.toString());
				student.setPassword(pwd.toString());
				list.add(student);
			}
		}
	}
}

//创建Excel
@RequestMapping("/createExcel")
public String createExcel(HttpServletResponse response) throws IOException {
 
	//创建HSSFWorkbook对象(excel的文档对象)
	HSSFWorkbook wb = new HSSFWorkbook();
	//建立新的sheet对象（excel的表单）
	HSSFSheet sheet=wb.createSheet("成绩表");
	//在sheet里创建第一行，参数为行索引(excel的行)，可以是0～65535之间的任何一个
	HSSFRow row1=sheet.createRow(0);
	//创建单元格（excel的单元格，参数为列索引，可以是0～255之间的任何一个
	HSSFCell cell=row1.createCell(0);
	//设置单元格内容
	cell.setCellValue("学员考试成绩一览表");
	//合并单元格CellRangeAddress构造参数依次表示起始行，截至行，起始列， 截至列
	sheet.addMergedRegion(new CellRangeAddress(0,0,0,3));
	//在sheet里创建第二行
	HSSFRow row2=sheet.createRow(1);
	//创建单元格并设置单元格内容
	row2.createCell(0).setCellValue("姓名");
	row2.createCell(1).setCellValue("班级");
	row2.createCell(2).setCellValue("笔试成绩");
	row2.createCell(3).setCellValue("机试成绩");
	//在sheet里创建第三行
	HSSFRow row3=sheet.createRow(2);
	row3.createCell(0).setCellValue("李明");
	row3.createCell(1).setCellValue("As178");
	row3.createCell(2).setCellValue(87);
	row3.createCell(3).setCellValue(78);
	//.....省略部分代码
	//输出Excel文件
	OutputStream output=response.getOutputStream();
	response.reset();
	response.setHeader("Content-disposition", "attachment; filename=details.xls");
	response.setContentType("application/msexcel");
	wb.write(output);
	output.close();
	return null;
}

public static String toUtf8String(String s){ 
     StringBuffer sb = new StringBuffer(); 
       for (int i=0;i<s.length();i++){ 
          char c = s.charAt(i); 
          if (c >= 0 && c <= 255){sb.append(c);} 
        else{ 
        byte[] b; 
         try { b = Character.toString(c).getBytes("utf-8");} 
         catch (Exception ex) { 
             System.out.println(ex); 
                  b = new byte[0]; 
         } 
            for (int j = 0; j < b.length; j++) { 
             int k = b[j]; 
              if (k < 0) k += 256; 
              sb.append("%" + Integer.toHexString(k).toUpperCase()); 
              } 
     } 
  } 
  return sb.toString(); 
}