第一步,添加依赖:
<!--poi-excel-->
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi</artifactId>
<version>3.6</version>
</dependency>
引入ExcelUtil 工具类:
public class ExcelUtil {
    /**
     * 导出Excel
     * @param sheetName sheet名称
     * @param title 标题
     * @param values 内容
     * @param wb HSSFWorkbook对象
     * @return
     */
    public static HSSFWorkbook getHSSFWorkbook(String sheetName,String []title,String [][]values, HSSFWorkbook wb){
        // 第一步,创建一个HSSFWorkbook,对应一个Excel文件
        if(wb == null){
            wb = new HSSFWorkbook();
        }
        // 第二步,在workbook中添加一个sheet,对应Excel文件中的sheet
        HSSFSheet sheet = wb.createSheet(sheetName);
        // 第三步,在sheet中添加表头第0行,注意老版本poi对Excel的行数列数有限制
        HSSFRow row = sheet.createRow(0);
        // 第四步,创建单元格,并设置值表头 设置表头居中
        HSSFCellStyle style = wb.createCellStyle();
        style.setAlignment(HSSFCellStyle.ALIGN_CENTER); // 创建一个居中格式
        //声明列对象
        HSSFCell cell = null;
        //创建标题
        for(int i=0;i<title.length;i++){
            cell = row.createCell(i);
            cell.setCellValue(title[i]);
            cell.setCellStyle(style);
        }
        //创建内容
        for(int i=0;i<values.length;i++){
            row = sheet.createRow(i + 1);
            for(int j=0;j<values[i].length;j++){
                //将内容按顺序赋给对应的列对象
                row.createCell(j).setCellValue(values[i][j]);
            }
        }
        return wb;
    }
}
在controller实现:
 
@RequestMapping("/export")
@ResponseBody
public void export(HttpServletRequest request, HttpServletResponse response) throws Exception {
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
    //获取数据
    List<BsAuthUser> list = bsAuthUserService.queryAllBsAuthUser();//查询到了所有的用户
    //excel标题
    String[] title = {"用户Id", "用户密码", "用户名", "创建日期", "状态"};
    //excel文件名
    String fileName = "用户表" + System.currentTimeMillis() + ".xls";
    //sheet名
    String sheetName = "用户信息表";
    String content[][] = new String[list.size()][title.length];
    for (int i = 0; i < list.size(); i++) {
        BsAuthUser obj = list.get(i);
        content[i][0] = obj.getAuthUserId().toString();
        content[i][1] = obj.getAuthPassword();
        content[i][2] = obj.getAuthUsername();
        content[i][3] = sdf.format(obj.getCreateDate());
        content[i][4] = obj.getState().toString();
    }
    //创建HSSFWorkbook
    HSSFWorkbook wb = ExcelUtil.getHSSFWorkbook(sheetName, title, content, null);
    //响应到客户端
    try {
        this.setResponseHeader(response, fileName);
        OutputStream os = response.getOutputStream();
        wb.write(os);
        os.flush();
        os.close();
    } catch (Exception e) {
        e.printStackTrace();
    }
}
//发送响应流方法
public void setResponseHeader(HttpServletResponse response, String fileName) {
    try {
        try {
            fileName = new String(fileName.getBytes(), "ISO8859-1");
        } catch (UnsupportedEncodingException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        response.setContentType("application/octet-stream;charset=ISO8859-1");
        response.setHeader("Content-Disposition", "attachment;filename=" + fileName);
        response.addHeader("Pargam", "no-cache");
        response.addHeader("Cache-Control", "no-cache");
    } catch (Exception ex) {
        ex.printStackTrace();
    }
}
下载地址是浏览器的默认下载地址。 
