java - 使用 JSP 上传 Word 文档

Question

我目前正在开发的程序允许用户浏览服务器上的文件，然后下载它们。对于下载，我编写了一个 JSP 将内容上传到客户端。它传递文件的名称，然后发回其内容。我下面的代码目前非常适合文本文件，但是当我尝试下载并打开一个 Word 文档(据我所知是一个二进制文件)时，我收到一些文本、一些奇怪的方 block 和来自 MS Word 的错误消息。我不确定为什么它错误地读取二进制数据。任何帮助将不胜感激。

    <%@ page import="java.io.*" %>

<%
    final File APP_ROOT = new File(com.mdi.core.config.ProcessConfiguration.getInstance().getStringValue("APP_ROOT"));
    File f = new File(request.getParameter("path"));

    File parent = f;
    boolean valid = false;
    while(!valid && (parent = parent.getParentFile()) != null)
    {
        valid = parent.equals(APP_ROOT);
    }
    if(!valid)
    {
        response.sendError(403, "You can not download this file!");
        return;
    }

    response.addHeader("Content-Disposition","attachment; filename="+f.getName());

    response.setContentLength((int)f.length());
    OutputStream os = response.getOutputStream();
    response.setContentType(java.net.URLConnection.guessContentTypeFromName(f.getName()));
    InputStream fin = null;
    try
    {
        fin = new FileInputStream(f);
        byte[] buff = new byte[512];
        int read;
        while((read = fin.read(buff)) != -1)
            os.write(buff, 0, read);
    }
    catch(Exception ex)
    {
        ex.printStackTrace();
    }
    finally
    {
        if(fin != null) fin.close();
    }       
%>

我还在标准输出中收到此错误。

java.net.ProtocolException: Exceeded stated content-length of: '40220' bytes
    at weblogic.servlet.internal.ServletOutputStreamImpl.checkCL(ServletOutputStreamImpl.java:200)
    at weblogic.servlet.internal.ServletOutputStreamImpl.write(ServletOutputStreamImpl.java:146)
    at jsp_servlet._mdi._html._file_upload.__default_file_upload._jspService(__default_file_upload.java:101)
    at weblogic.servlet.jsp.JspBase.service(JspBase.java:34)
    at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:227)
    at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:125)
    at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:300)
    at weblogic.servlet.internal.TailFilter.doFilter(TailFilter.java:26)
    at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
    at com.mdi.core.utils.http.SecurityFilter.doFilter(SecurityFilter.java:154)
    at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
    at com.mdi.core.utils.http.ResponseHeaderFilter.doFilter(ResponseHeaderFilter.java:69)
    at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
    at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.wrapRun(WebAppServletContext.java:3715)
    at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.run(WebAppServletContext.java:3681)
    at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:321)
    at weblogic.security.service.SecurityManager.runAs(SecurityManager.java:120)
    at weblogic.servlet.internal.WebAppServletContext.securedExecute(WebAppServletContext.java:2277)
    at weblogic.servlet.internal.WebAppServletContext.execute(WebAppServletContext.java:2183)
    at weblogic.servlet.internal.ServletRequestImpl.run(ServletRequestImpl.java:1454)
    at weblogic.work.ExecuteThread.execute(ExecuteThread.java:209)
    at weblogic.work.ExecuteThread.run(ExecuteThread.java:178)
<Jun 27, 2014 10:46:07 AM EDT> <Error> <HTTP> <BEA-101083> <Connection failure.
java.net.ProtocolException: Didn't meet stated Content-Length, wrote: '39942' bytes instead of stated: '40220' bytes.
    at weblogic.servlet.internal.ServletOutputStreamImpl.ensureContentLength(ServletOutputStreamImpl.java:446)
    at weblogic.servlet.internal.ServletResponseImpl.ensureContentLength(ServletResponseImpl.java:1432)
    at weblogic.servlet.internal.ServletResponseImpl.send(ServletResponseImpl.java:1511)
    at weblogic.servlet.internal.ServletRequestImpl.run(ServletRequestImpl.java:1462)
    at weblogic.work.ExecuteThread.execute(ExecuteThread.java:209)
    Truncated. see log file for complete stacktrace
> 
<Jun 27, 2014 10:46:07 AM EDT> <Error> <HTTP> <BEA-101104> <Servlet execution in servlet context "ServletContext@1188950474[app:Trade module:TA15 path:/TA15 spec-version:null]" failed, java.net.ProtocolException: Didn't meet stated Content-Length, wrote: '39942' bytes instead of stated: '40220' bytes..
java.net.ProtocolException: Didn't meet stated Content-Length, wrote: '39942' bytes instead of stated: '40220' bytes.
    at weblogic.servlet.internal.ServletOutputStreamImpl.ensureContentLength(ServletOutputStreamImpl.java:446)
    at weblogic.servlet.internal.ServletResponseImpl.ensureContentLength(ServletResponseImpl.java:1432)
    at weblogic.servlet.internal.ServletResponseImpl.send(ServletResponseImpl.java:1511)
    at weblogic.servlet.internal.ServletRequestImpl.run(ServletRequestImpl.java:1462)
    at weblogic.work.ExecuteThread.execute(ExecuteThread.java:209)
    Truncated. see log file for complete stacktrace

Answer 1

非常重要的是去掉JSP自己的空白输出:

<%@ page contentType="application/octet" import="java.io.*" %><%
%>

最后一行没有空格，也没有换行符。提示:使用 servlet。

不知何故，仍然需要完成os.flush()。

来自@BoristheSpide 的评论:忘记冲洗。我认为空格引起了一些问题，将内容类型添加为二进制数据。