Java poi导出Excel下载到客户端

<dependency>
      <groupid>org.apache.poi</groupid>
      <artifactid>poi-excelant</artifactid>
      <version>3.12</version>
    </dependency>
    <dependency>
      <groupid>org.apache.poi</groupid>
      <artifactid>poi-scratchpad</artifactid>
      <version>3.12</version>
    </dependency>
    <dependency>
      <groupid>org.apache.poi</groupid>
      <artifactid>poi-ooxml</artifactid>
      <version>3.8</version>
    </dependency>
    <dependency>
      <groupid>org.apache.poi</groupid>
      <artifactid>poi-ooxml-schemas</artifactid>
      <version>3.8</version>
    </dependency>

@override
  public void export(long sblsh, string excelname, outputstream out) {
    try {
      // 第一步，创建一个webbook，对应一个excel文件 
      hssfworkbook wb = new hssfworkbook();
      //生成一个表格 
      hssfsheet sheet = wb.createsheet(excelname); 
      // 第三步，在sheet中添加表头第0行
      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
      hssfcell cell = row.createcell(0);
      cell.setcellstyle(style);
      
      byte kjzz = qyjbxxmapper.getkjzz(sblsh);
      list<a> record = this.selectbysblsh(sblsh);
        this.insertdata(wb, sheet, row, record, out);
      }
    } catch (exception e) {
      logger.info(e.getmessage());
    }
  }
  
  /**
   * 导入数据到表格中
   * @param wb execl文件
   * @param sheet 表格
   * @param row 表格行
   * @param record 要导出的数据
   * @param out 输出流
   */
  private void insertdata(hssfworkbook wb,hssfsheet sheet,hssfrow row,list<a> record,
      outputstream out){
    try {
      row = sheet.createrow(1);
      for(int i=0;i<title.length;i++){
        row.createcell(i).setcellvalue(title[i]);
      }
      for(int i=0;i<record.size();i++){
        row = sheet.createrow(i+2);
        a data = record.get(i);
        row.createcell(0).setcellvalue(data.gethc());
        row.createcell(1).setcellvalue(data.getxm());
        bigdecimal je = data.getje();
        if(je!=null){
          row.createcell(2).setcellvalue(je.doublevalue());
        }
      }
      //合并单元格，前面2位代表开头结尾行，后面2位代表开头结尾列
      cellrangeaddress region = new cellrangeaddress(0,0,0,title.length-1);
      sheet.addmergedregion(region);
      wb.write(out);
      out.flush();
      out.close();
      wb.close();
    } catch (exception e) {
      logger.info(e.getmessage());
    }
  }

@requestmapping("/export")
  public void export(long sblsh, httpservletrequest request, httpservletresponse response){
    response.setcontenttype("octets/stream");
    string excelname = "文件名";
    try {
      response.addheader("content-disposition", "attachment;filename="+new string(excelname.getbytes("gb2312"), "iso8859-1" )+".xls");
      outputstream out = response.getoutputstream();
      aservice.export(sblsh,excelname ,out);
    } catch (exception e) {
      e.printstacktrace();
    }
  }