网页导出excel

工具，以输出流的形式导出excel文件

package com.zhiyou.usermanage.util;

import java.io.OutputStream;
import java.util.Date;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;

import javax.servlet.http.HttpServletResponse;

import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.joda.time.DateTime;


public class ExportExcel {
      public static void exportXls(List<Map<String,Object>> list,HttpServletResponse response) throws Exception {
           OutputStream os=response.getOutputStream();//取得输出流
           response.reset();//清空输出流
           response.setHeader("Content-disposition", "attachment; filename=test.xls");// 设定输出文件头
           response.setContentType("application/msexcel");// 定义输出类型
            HSSFWorkbook workbook = new HSSFWorkbook();
         // 创建Excel的sheet
            HSSFSheet sheet = workbook.createSheet("用户");
            sheet.setForceFormulaRecalculation(true);
            // 根据模板中表达式位置， 修改对应单元格的值
            //创建表格头
            Map<String, Object> first=list.get(0);
            HSSFRow header=sheet.createRow(0);
            int headerColNum=0;
            for(Entry<String, Object> e:first.entrySet()) {
                header.createCell(headerColNum).setCellValue(e.getKey());
                headerColNum++;
            }
            int rowNum = 1;
            for (Map<String, Object> map : list) {
                    HSSFRow row = sheet.createRow(rowNum);
                    int colNum=0;
                    for (String key : map.keySet()) {
                            if(map.get(key) instanceof Date) {
                                    row.createCell(colNum).setCellValue(new DateTime(map.get(key)).toString(Constants.DATE_TIME));
                            }else {
                                row.createCell(colNum).setCellValue(map.get(key).toString());
                            }
                            colNum++;
                                    }
                    rowNum++;
            }
            workbook.write(os);
            os.close();
        }
}

其中的Constants类

package com.zhiyou.usermanage.util;

public interface Constants {

    public String DATE = "yyyy-MM-dd";

    public String DATE_TIME = "yyyy-MM-dd hh:mm:ss";

}

映射文件，按顺序存放了字段头信息，在导出过程中只需选取第一行的key值写出表格头

<select id="selectExport" resultType="java.util.LinkedHashMap">
      select <include refid="Base_Column_List"/> from tb_user
  </select>