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