Java Web利用POI导出Excel简单例子

采用Spring mvc架构：

Controller层代码如下

@Controller  
public class StudentExportController{  
  
    @Autowired  
    private StudentExportService studentExportService;  
  
    @RequestMapping(value = "/excel/export")  
    public void exportExcel(HttpServletRequest request, HttpServletResponse response)   
    throws Exception {  
          
        List<Student> list = new ArrayList<Student>();  
        list.add(new Student(1000,"zhangsan","20"));  
        list.add(new Student(1001,"lisi","23"));  
        list.add(new Student(1002,"wangwu","25"));  
        HSSFWorkbook wb = studentExportService.export(list);  
        response.setContentType("application/vnd.ms-excel");  
        response.setHeader("Content-disposition", "attachment;filename=student.xls");  
        OutputStream ouputStream = response.getOutputStream();  
        wb.write(ouputStream);  
        ouputStream.flush();  
        ouputStream.close();  
   }  
}  

Service层代码如下：

@Service  
public class StudentExportService {  
  
    String[] excelHeader = { "Sno", "Name", "Age"};  
    public HSSFWorkbook export(List<Campaign> list) {  
        HSSFWorkbook wb = new HSSFWorkbook();  
        HSSFSheet sheet = wb.createSheet("Campaign");  
        HSSFRow row = sheet.createRow((int) 0);  
        HSSFCellStyle style = wb.createCellStyle();  
        style.setAlignment(HSSFCellStyle.ALIGN_CENTER);  
  
        for (int i = 0; i < excelHeader.length; i++) {  
            HSSFCell cell = row.createCell(i);  
            cell.setCellValue(excelHeader[i]);  
            cell.setCellStyle(style);  
            sheet.autoSizeColumn(i);  
        }  
  
        for (int i = 0; i < list.size(); i++) {  
            row = sheet.createRow(i + 1);  
            Student student = list.get(i);  
            row.createCell(0).setCellValue(student.getSno());  
            row.createCell(1).setCellValue(student.getName());  
            row.createCell(2).setCellValue(student.getAge());  
        }  
        return wb;  
    }  
}  

前台的js代码如下：

<script>  
function exportExcel(){  
     location.href="excel/export";  
     <!--这里不能用ajax请求，ajax请求无法弹出下载保存对话框-->  
 }  
</script>  

设置Excel样式以及注意点：

	String[] excelHeader = { "所属区域（地市）", "机房", "机架资源情况", "", "", "", "",
		"", "端口资源情况", "", "", "", "", "", "机位资源情况", "", "", "设备资源情况",
		"", "", "IP资源情况", "", "", "", "", "网络设备数" };
	String[] excelHeader1 = { "", "", "总量(个)", "空闲(个)", "预占(个)", "实占(个)",
		"自用(个)", "其它(个)", "总量(个) ", "在用(个)", "空闲(个)", "总带宽(M)",
		"在用带宽(M)", "空闲带宽(M)", "总量(个)", "在用(个)", "空闲(个)", "设备总量(个)",
		"客户设备(个)", "电信设备(个)", "总量(个)", "空闲(个)", "预占用(个)", "实占用(个)",
		"自用(个)", "" };
	// 单元格列宽
	int[] excelHeaderWidth = { 150, 120, 100, 100, 100, 100, 100, 100, 100,
		100, 100, 120, 120, 120, 120, 120, 120, 150, 150, 150, 120,
		120, 150, 150, 120, 150 };

	HSSFWorkbook wb = new HSSFWorkbook();
	HSSFSheet sheet = wb.createSheet("机房报表统计");
	HSSFRow row = sheet.createRow((int) 0);
	HSSFCellStyle style = wb.createCellStyle();
	// 设置居中样式
	style.setAlignment(HSSFCellStyle.ALIGN_CENTER); // 水平居中
	style.setVerticalAlignment(HSSFCellStyle.VERTICAL_CENTER); // 垂直居中

	// 设置合计样式
	HSSFCellStyle style1 = wb.createCellStyle();
	Font font = wb.createFont();
	font.setColor(HSSFColor.RED.index);
	font.setBoldweight(Font.BOLDWEIGHT_BOLD); // 粗体
	style1.setFont(font);
	style1.setAlignment(HSSFCellStyle.ALIGN_CENTER); // 水平居中
	style1.setVerticalAlignment(HSSFCellStyle.VERTICAL_CENTER); // 垂直居中

	// 合并单元格
	// first row (0-based) last row (0-based) first column (0-based) last
	// column (0-based)
	sheet.addMergedRegion(new CellRangeAddress(0, 1, 0, 0));
	sheet.addMergedRegion(new CellRangeAddress(0, 1, 1, 1));
	sheet.addMergedRegion(new CellRangeAddress(0, 0, 2, 7));
	sheet.addMergedRegion(new CellRangeAddress(0, 0, 8, 13));
	sheet.addMergedRegion(new CellRangeAddress(0, 0, 14, 16));
	sheet.addMergedRegion(new CellRangeAddress(0, 0, 17, 19));
	sheet.addMergedRegion(new CellRangeAddress(0, 0, 20, 24));
	sheet.addMergedRegion(new CellRangeAddress(0, 1, 25, 25));
	// 设置列宽度（像素）
	for (int i = 0; i < excelHeaderWidth.length; i++) {
	    sheet.setColumnWidth(i, 32 * excelHeaderWidth[i]);
	}

	// 添加表格头
	for (int i = 0; i < excelHeader.length; i++) {
	    HSSFCell cell = row.createCell(i);
	    cell.setCellValue(excelHeader[i]);
	    cell.setCellStyle(style);
	}
	row = sheet.createRow((int) 1);
	for (int i = 0; i < excelHeader1.length; i++) {
	    HSSFCell cell = row.createCell(i);
	    cell.setCellValue(excelHeader1[i]);
	    cell.setCellStyle(style);
	}

注意点1：合并单元格 new CellRangeAddress(int,int,int,int)

first row (0-based) ,last row (0-based), first column (0-based),last column (0-based)

注意点2：合并单元格

String[] excelHeader = { "所属区域（地市）", "机房", "机架资源情况", "", "", "", "","", "端口资源情况", "", "", "", "", "", "机位资源情况", "", "", "设备资源情况","", "", "IP资源情况", "", "", "", "", "网络设备数" };

合并以后的单元格虽然是一个，但是仍然要保留其单元格内容，此处用空字符串代替，否则后续表头显示不出

注意点3：填充单元格

正确写法：

HSSFCell cell = row.createCell(i);

cell.setCellValue(excelHeader1[i]);

cell.setCellStyle(style);

错误写法：

row.createCell(i).setCellValue(excelHeader1[i]);

row.createCell(i).setCellStyle(style);

本人为了省一个HSSFCell对象，使用了错误写法，导致HSSFCell对象创建了2次，最后只保留了样式，而内容无法显示