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java.lang.IllegalStateException：已经使用输出流[关闭]

jsp

当用户单击按钮时，客户端浏览器上的windchill GUI应该在其系统上下载特定的pdf文件。我通过使用以下代码实现了这一点。

   <body>
    <%
    String pdfname=   session.getAttribute("pdfname").toString();
    String Pdfpath=   session.getAttribute("pdfpath").toString();
    File f =new File(Pdfpath);
     Boolean flag=false;
      if(f.exists())
      {
     BufferedInputStream filein = null;
     BufferedOutputStream out2=null;
    try {
    File file = new File(Pdfpath);//specify the file path
    byte b[] = new byte[1048576];
    int len = 0;
    filein = new BufferedInputStream(new FileInputStream(file));
    out2=new BufferedOutputStream(response.getOutputStream());
    response.setHeader("Content-Length", ""+file.length());
    response.setContentType("application/pdf");
    response.setHeader("Content-Disposition","attachment;filename="+pdfname);
    response.setHeader("Content-Transfer-Encoding", "binary");
    while ((len = filein.read(b)) > 0) {
    out2.write(b, 0, len);
    out.println("Your Pdf Document Is Generated Please close it");
    }
    filein.close();
    out2.flush();
    out2.close();
  }
    catch(Exception e)
{
    out.println(e);
    }

      }else{

        String error ="File Not Found Or File Has Bean Deleted Already";
        request.setAttribute("error", error);
        RequestDispatcher s = request.getRequestDispatcher("NoFile.jsp");
                s.forward(request, response);
    }
     %>
    </body>

这段代码可以正常工作并且正在下载文件，但是之后它会引发异常。以下是我的方法服务器日志

ERROR : org.apache.catalina.core.ContainerBase.[Catalina].[localhost].[/Windchill].[jsp]  - Servlet.service() for servlet jsp threw exception
Thu 3/28/13 12:29:07: TP-Processor7: java.lang.IllegalStateException: Already using output stream
Thu 3/28/13 12:29:07: TP-Processor7:    at wt.servlet.CompressionFilter$GzippingResponse.getWriter(CompressionFilter.java:860)
Thu 3/28/13 12:29:07: TP-Processor7:    at org.apache.jasper.runtime.JspWriterImpl.initOut(JspWriterImpl.java:125)
Thu 3/28/13 12:29:07: TP-Processor7:    at org.apache.jasper.runtime.JspWriterImpl.flushBuffer(JspWriterImpl.java:118)
Thu 3/28/13 12:29:07: TP-Processor7:    at org.apache.jasper.runtime.JspWriterImpl.flush(JspWriterImpl.java:173)
Thu 3/28/13 12:29:07: TP-Processor7:    at org.apache.jasper.runtime.JspWriterImpl.close(JspWriterImpl.java:187)
Thu 3/28/13 12:29:07: TP-Processor7:    at org.apache.jsp.netmarkets.jsp.gt.get_jsp._jspService(get_jsp.java:105)
Thu 3/28/13 12:29:07: TP-Processor7:    at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
Thu 3/28/13 12:29:07: TP-Processor7:    at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
Thu 3/28/13 12:29:07: TP-Processor7:    at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:388)
Thu 3/28/13 12:29:07: TP-Processor7:    at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
Thu 3/28/13 12:29:07: TP-Processor7:    at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
Thu 3/28/13 12:29:07: TP-Processor7:    at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
Thu 3/28/13 12:29:07: TP-Processor7:    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
Thu 3/28/13 12:29:07: TP-Processor7:    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
Thu 3/28/13 12:29:07: TP-Processor7:    at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:646)
Thu 3/28/13 12:29:07: TP-Processor7:    at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:436)
Thu 3/28/13 12:29:07: TP-Processor7:    at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:374)
Thu 3/28/13 12:29:07: TP-Processor7:    at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:302)
Thu 3/28/13 12:29:07: TP-Processor7: ......

......

谷歌上有很多关于此异常的帖子，但我无法清除我的错误。我也尝试将其添加到servlet中而不是jsp中。这也显示了相同的异常。这种方式是否适合下载文件，或者我的方式错误？我需要帮助

谢谢


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2020-06-08

共1个答案

小编典典

您不能同时使用getServletOutputStream()和getWriter()在同一响应中使用。

来解决你的问题。避免在JSP中编写脚本。无论您在JSP中做什么，都可以在Servlet中实现它。

您正在使用response.getOutputStream();非法的JSP
进行调用。您应该使用ServletResponse.getOutputStream()或ServletResponse.getWriter()。由于JSP默认使用ServletResponse.getWriter（）。您应该写到ServletResponse.getWriter（）而不是ServletResponse.getOutputStream（）

这就是Java Doc所说的：

getOutputStream …

ServletOutputStream getOutputStream（）引发IOException

返回适合于在响应中写入二进制数据的ServletOutputStream。Servlet容器不对二进制数据进行编码。

在ServletOutputStream上调用flush（）会提交响应。可以调用此方法或getWriter（）来编写正文，而不能同时调用两者。

返回：用于写入二进制数据的ServletOutputStream 抛出：IllegalStateException-
如果已在此响应上调用getWriter方法。

2020-06-08