java - java中写入excel时出现错误

Question

我不知道问题出在哪里。我尝试过，但错误仍然存​​在。

我的程序是导出到 Excel，我使用的是 apache poi api。

下面是我的代码。编辑:

public void exportToExcel(ValueObjectList columnBody, String pageDef, ValueObject vo){
    try {
    HttpServletResponse response = vo.getResponse();

     SimpleDateFormat sd = new SimpleDateFormat("ddMMyy");
     Date dt = new Date();
    response.setContentType("application/vnd.ms-excel");
    if(pageDef == "promo" || pageDef.equals("promo"))
        response.setHeader("Content-Disposition", "attachment; filename=PROMO-" + sd.format(dt) + ".xls");
    else if(pageDef == "incomplete" || pageDef.equals("incomplete"))
        response.setHeader("Content-Disposition", "attachment; filename=INCOM-" + sd.format(dt) + ".xls");
    else
         response.setHeader("Content-Disposition", "attachment; filename=ST-" + sd.format(dt) + ".xls");


    // create a small spreadsheet
     HSSFWorkbook wb = new HSSFWorkbook();
     HSSFSheet sheet = wb.createSheet();

     HSSFRow row = null;
     HSSFCell cell = null;

     //set default font properties
     //font family: Arial
     //font weight: bold
     Font headerFont = wb.createFont();
     headerFont.setBoldweight(Font.BOLDWEIGHT_BOLD);

     headerFont.setFontHeightInPoints((short)14);

     //Cell Style for header
     CellStyle csHeader = wb.createCellStyle();
     csHeader.setFont(headerFont);
     csHeader.setBorderBottom(csHeader.BORDER_THICK);
     csHeader.setFillForegroundColor(HSSFColor.GREY_25_PERCENT.index);
     csHeader.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);
     csHeader.setWrapText(true);

     //Cell Style for body
     CellStyle csBody = wb.createCellStyle();
     csBody.setWrapText(true);
     csBody.setAlignment(HSSFCellStyle.ALIGN_CENTER);


     String[] columnHeader = ((ValueObject)columnBody.get(0)).toKeyArray();
     //System.out.println("Header Length: " + columnHeader.length);

     row = sheet.createRow(0);
     cell = row.createCell(0);
     cell.setCellValue("No");
     cell.setCellStyle(csHeader);

     for(int h = 0; h < columnHeader.length; h++){
         cell = row.createCell(h+1);
         cell.setCellValue(columnHeader[h]);
         cell.setCellStyle(csHeader);
         sheet.autoSizeColumn(h+1);
         //sheet.setColumnWidth(h, 2000);
     }

     //System.out.println("header key : " + columnHeader[2]);
    //System.out.println("header value : " + testobj.get(testobj.toKeyArray()[2]));

     for(int i = 0; i < columnBody.size(); i++){
         row = sheet.createRow(i+1);
         cell = row.createCell(0);
         cell.setCellValue(i+1);
         cell.setCellStyle(csBody);
         ValueObject column = (ValueObject)columnBody.get(i);
         for(int j = 0; j < column.size(); j++){
             cell = row.createCell(j+1);
             cell.setCellValue(column.get(column.toKeyArray()[j]));
             cell.setCellStyle(csBody);
             sheet.autoSizeColumn(j+1);
         }
     }


     /*
     // write it as an excel attachment
     ByteArrayOutputStream outByteStream = new ByteArrayOutputStream();
     wb.write(outByteStream);
     byte [] outArray = outByteStream.toByteArray();
     response.setContentType("application/ms-excel");
     response.setContentLength(outArray.length);
     response.setHeader("Expires:", "0"); // eliminates browser caching
     if(pageDef == "promo" || pageDef.equals("promo"))
        response.setHeader("Content-Disposition", "attachment; filename=PROMO-" + sd.format(dt) + ".xls");
     else if(pageDef == "incomplete" || pageDef.equals("incomplete"))
        response.setHeader("Content-Disposition", "attachment; filename=INCOM-" + sd.format(dt) + ".xls");
     else
         response.setHeader("Content-Disposition", "attachment; filename=ST-" + sd.format(dt) + ".xls");

     OutputStream outStream = response.getOutputStream();
     outStream.write(outArray);
     outStream.flush();
     */


     ByteArrayOutputStream outByteStream = new ByteArrayOutputStream(wb.getBytes().length);
     wb.write(outByteStream);


    } catch (Exception e) {
        log.error(e);
        e.printStackTrace();
    }
}

我尝试在谷歌上冲浪并尝试解决但不行。

首先，我在jsp中编写了这些代码。

当我在 google 上冲浪时，人们说我必须在 servlet 中使用，所以我转向 servlet，但仍然出现错误。

英语不是我的母语。抱歉，如果我输入错误。

提前致谢。

Answer 1

我猜你的错误与这段代码有关(不是 apache poi api):

OutputStream outStream = response.getOutputStream();
outStream.write(outArray);
outStream.flush();
outStream.close();

因为您要刷新并关闭 Servlet 中的输出流，所以在响应返回到客户端之前尝试写入输出流的任何操作都将导致抛出 IllegalStateException。 通常最好将flush()和close()留给servlet容器，除非你真的知道你在做什么。
尝试删除flush()和close()，并检查您拥有的其他servlet是否也在做同样的事情。