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