相信导出excel功能，是制作报表必不可少的功能之一，最近这几天，本人也是花了一番心思来编写这个功能，现在拿出来与大家分享一下，同时也是对自己的一个总结。
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1.首先需要写一个导出excel的工具类。
public class ExcelUtil{
public static String NO_DEFINE = "no_define";//未定义的字段
public static String DEFAULT_DATE_PATTERN="yyyy年MM月dd日";//默认日期格式
public static int DEFAULT_COLOUMN_WIDTH = 17;
/**
* 导出Excel 97(.xls)格式 ，少量数据
* @param title 标题行
* @param headMap 属性-列名
* @param jsonArray 数据集
* @param datePattern 日期格式，null则用默认日期格式
* @param colWidth 列宽 默认 至少17个字节
* @param out 输出流
*/
public static void exportExcel(String title,Map<String, String> headMap,JSONArray jsonArray,String datePattern,int colWidth, OutputStream out) {
if(datePattern==null) datePattern = DEFAULT_DATE_PATTERN;
// 声明一个工作薄
HSSFWorkbook workbook = new HSSFWorkbook();
//表头样式
HSSFCellStyle titleStyle = workbook.createCellStyle();
titleStyle.setAlignment(HSSFCellStyle.ALIGN_CENTER);
HSSFFont titleFont = workbook.createFont();
titleFont.setFontHeightInPoints((short) 20);
titleFont.setBoldweight((short) 700);
titleStyle.setFont(titleFont);
// 列头样式
HSSFCellStyle headerStyle = workbook.createCellStyle();
headerStyle.setFillBackgroundColor((short) 131);
headerStyle.setBorderBottom(HSSFCellStyle.BORDER_THIN);
headerStyle.setBorderLeft(HSSFCellStyle.BORDER_THIN);
headerStyle.setBorderRight(HSSFCellStyle.BORDER_THIN);
headerStyle.setBorderTop(HSSFCellStyle.BORDER_THIN);
headerStyle.setAlignment(HSSFCellStyle.ALIGN_CENTER);
HSSFFont headerFont = workbook.createFont();
headerFont.setFontHeightInPoints((short) 12);
headerFont.setBoldweight(HSSFFont.BOLDWEIGHT_BOLD);
headerStyle.setFont(headerFont);
// 单元格样式
HSSFCellStyle cellStyle = workbook.createCellStyle();
cellStyle.setBorderBottom(HSSFCellStyle.BORDER_THIN);
cellStyle.setBorderLeft(HSSFCellStyle.BORDER_THIN);
cellStyle.setBorderRight(HSSFCellStyle.BORDER_THIN);
cellStyle.setBorderTop(HSSFCellStyle.BORDER_THIN);
cellStyle.setAlignment(HSSFCellStyle.ALIGN_CENTER);
cellStyle.setVerticalAlignment(HSSFCellStyle.VERTICAL_CENTER);
HSSFFont cellFont = workbook.createFont();
cellFont.setBoldweight(HSSFFont.BOLDWEIGHT_NORMAL);
cellStyle.setFont(cellFont);
// 生成一个(带标题)表格
HSSFSheet sheet = workbook.createSheet();
// 声明一个画图的顶级管理器
HSSFPatriarch patriarch = sheet.createDrawingPatriarch();
// 定义注释的大小和位置,详见文档
HSSFComment comment = patriarch.createComment(new HSSFClientAnchor(0,
0, 0, 0, (short) 4, 2, (short) 6, 5));
// 设置注释内容
comment.setString(new HSSFRichTextString("可以在POI中添加注释！"));
// 设置注释作者，当鼠标移动到单元格上是可以在状态栏中看到该内容.
comment.setAuthor("JACK");
//设置列宽
int minBytes = colWidth<DEFAULT_COLOUMN_WIDTH?DEFAULT_COLOUMN_WIDTH:colWidth;//至少字节数
int[] arrColWidth = new int[headMap.size()];
// 产生表格标题行,以及设置列宽
String[] properties = new String[headMap.size()];
String[] headers = new String[headMap.size()];
int ii = 0;
for (Iterator<String> iter = headMap.keySet().iterator(); iter
.hasNext();) {
String fieldName = iter.next();
properties[ii] = fieldName;
headers[ii] = headMap.get(fieldName);
int bytes = fieldName.getBytes().length;
arrColWidth[ii] = bytes < minBytes ? minBytes : bytes;
sheet.setColumnWidth(ii,arrColWidth[ii]*256);
ii++;
}
// 遍历集合数据，产生数据行
int rowIndex = 0;
for (int m=0;m<jsonArray.size();m++) {
JSONObject jo = jsonArray.getJSONObject(m);
if(rowIndex == 65535 || rowIndex == 0){
if ( rowIndex != 0 ) sheet = workbook.createSheet();//如果数据超过了，则在第二页显示
if(title!=null&&!"".equals(title)&&!"null".equals(title)){
HSSFRow titleRow = sheet.createRow(0);//表头 rowIndex=0
titleRow.createCell(0).setCellValue(title);
titleRow.getCell(0).setCellStyle(titleStyle);
sheet.addMergedRegion(new CellRangeAddress(0, 0, 0, headMap.size() - 1));
}
HSSFRow headerRow = sheet.createRow(1); //列头 rowIndex =1
for(int i=0;i<headers.length;i++)
{
headerRow.createCell(i).setCellValue(headers[i]);
headerRow.getCell(i).setCellStyle(headerStyle);
}
rowIndex = 2;//数据内容从 rowIndex=2开始
}
HSSFRow dataRow = sheet.createRow(rowIndex);
for (int i = 0; i < properties.length; i++)
{
HSSFCell newCell = dataRow.createCell(i);
Object o = jo.get(properties[i]);
String cellValue = "";
if(o==null) cellValue = "";
else if(o instanceof Date) cellValue = new SimpleDateFormat(datePattern).format(o);
else cellValue = o.toString();
newCell.setCellValue(cellValue);
newCell.setCellStyle(cellStyle);
}
rowIndex++;
}
// 自动调整宽度
/*for (int i = 0; i < headers.length; i++) {
sheet.autoSizeColumn(i);
}*/
try {
workbook.write(out);
workbook = null;
} catch (IOException e) {
e.printStackTrace();
}
}
//Web 导出excel
/**
* title
* - Excel的表头标题
* fileName
* - 文件名
*/
public static void downloadExcelFile(String title,String fileName,Map<String,String> headMap,JSONArray ja,HttpServletResponse response){
try {
ByteArrayOutputStream os = new ByteArrayOutputStream();
ExcelUtil.exportExcel(title,headMap,ja,null,0,os);
byte[] content = os.toByteArray();
InputStream is = new ByteArrayInputStream(content);
// 设置response参数，可以打开下载页面
response.reset();
response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet;charset=utf-8");
response.setHeader("Content-Disposition", "attachment;filename="+ new String((fileName + ".xls").getBytes(), "iso-8859-1"));
response.setContentLength(content.length);
ServletOutputStream outputStream = response.getOutputStream();
BufferedInputStream bis = new BufferedInputStream(is);
BufferedOutputStream bos = new BufferedOutputStream(outputStream);
byte[] buff = new byte[8192];
int bytesRead;
while (-1 != (bytesRead = bis.read(buff, 0, buff.length))) {
bos.write(buff, 0, bytesRead);
}
bis.close();
bos.close();
outputStream.flush();
outputStream.close();
}catch (Exception e) {
e.printStackTrace();
}
}
}——————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————
2.工具类写好以后便是使用这个工具类的方法。
可以看出，这个工具类导出excel的方法叫做downloadExcelFile(String title,String fileName,Map<String,String> headMap,JSONArray ja,HttpServletResponse response)；
它需要传入的参数分别是String，string，map，jsonarray和一个response；
第一个string标题，可以不写直接写null。
第二个string是下载的文件名。
第三个map是你要传入的excel的表头设置和字段设置。
第四个jsonarr是你传入的数据json化。
第五个是response。
本人暂时使用的框架是ssh，所以里面为acton，方法如下。
public String exportWorkExcel() throws Exception {
//
String dateformat = "yyyy-MM-dd HH:mm:ss";
//生成一个按时间格式的文件名
String fileformat = "yyyyMMddHHmmss";
SimpleDateFormat sf = new SimpleDateFormat(fileformat);
Calendar cal = Calendar.getInstance();
String filename = (String)getRequest().getParameter("exportfilename");
if(filename==null){
filename = "";
}
filename += "_" + sf.format(cal.getTime());
//·······································································
//得到你想要打印的表格的list集合。
//例如list<Work> list;
//········································································
Map<String, String> headMap = new LinkedHashMap<String, String>();
headMap.put("workname", "文号");
//```````````````````````````````````````````````````````````````````````
//设计你的excel的表头和对应的字段
//·······································································
JSONArray arr = new JSONArray();
if(list!=null&&list.size()>0){
for(Work hw:list){
//把属性以键值对的形式放到map中
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
LinkedHashMap<String, String> ss = new LinkedHashMap<String, String>();
ss.put("workname", hw.getWorkName());
//······································································································
//把map转换成json对象，并且添加到jsonarr中
//·······································································································
JSONObject jsonObj = JSONObject.fromObject(ss);
arr.add(jsonObj);
}
/***********如果找到list装有一个完整的实体类，可以直接调用下面这个方法，便可以直接得到对应的jsonarr*******************/
/*arr = JsonBeanUtil.beanListToJsonArray(renotList,dateformat);*/
}
ExcelUtil.downloadExcelFile(null,filename, headMap, arr, getResponse());
return null;
}
3.前端调用此方法，大功告成！！！！
注意：本人使用的jar包为poi1，如果使用高版本的poi一些工具类中的字段可能不一样，只需要更改里面的字段便可以了。
