运行上传文件代码时出现HTTP状态404错误

Question

单击提交按钮时出现错误“ HTTP状态404-找不到”。 给出的路径似乎是正确的。 关于此代码，是否有任何会导致该错误发生的事情？

<form name="uploadForm" action="index.jsp" method="POST" enctype="multipart/form-data">
        <%
            String saveFile="";
            String contentType = request.getContentType();

            if((contentType != null)&&(contentType.indexOf("multipart/form-data") >= 0)){

                DataInputStream in = new DataInputStream(request.getInputStream());
                int formDataLength = request.getContentLength();
                byte dataBytes[] = new byte[formDataLength];
                int byteRead = 0;
                int totalBytesRead = 0;

                while(totalBytesRead < formDataLength){
                    byteRead = in.read(dataBytes, totalBytesRead,formDataLength);
                    totalBytesRead += byteRead;
                }

                String file = new String(dataBytes);
                saveFile = file.substring(file.indexOf("filename=\"") + 10);
                saveFile = saveFile.substring(0, saveFile.indexOf("\n"));
                saveFile = saveFile.substring(saveFile.lastIndexOf("\\") + 1,saveFile.indexOf("\""));
                int lastIndex = contentType.lastIndexOf("=");
                String boundary = contentType.substring(lastIndex + 1,contentType.length());
                int pos;
                pos = file.indexOf("filename=\"");
                pos = file.indexOf("\n", pos) + 1;
                pos = file.indexOf("\n", pos) + 1;
                pos = file.indexOf("\n", pos) + 1;
                int boundaryLocation = file.indexOf(boundary, pos) - 4;
                int startPos = ((file.substring(0, pos)).getBytes()).length;
                int endPos = ((file.substring(0, boundaryLocation)).getBytes()).length;

                File ff = new File("C:/Users/JBG/Desktop/SampleFile2.docx"+saveFile);

                try{
                    FileOutputStream fileOut = new FileOutputStream(ff);
                    fileOut.write(dataBytes, startPos, (endPos - startPos));
                    fileOut.flush();
                    fileOut.close();}catch(Exception e){out.println(e);}
            }
        %>

        <input type="file" name="file" value="" />
        <input type="submit" value="Submit" name="submit" />
    </form>

Answer 1

当您收到404错误消息时。 此错误消息表明

The 404 or Not Found error message is a HTTP standard response code indicating that the client was able to communicate with a given server, but the server could not find what was requested.

The web site hosting server will typically generate a "404 Not Found" web page when a user attempts to follow a broken or dead link; hence the 404 error is one of the most recognizable errors users can find on the web.[1]

因此，在文件操作纠正以下行时会出现一些错误。

在你的代码中

File ff = new File("C:/Users/JBG/Desktop/SampleFile2.docx"+saveFile);

替换下面的语法。

File ff = new File("C:/Users/JBG/Desktop/directory_name/"+saveFile);

要么

File ff = new File("C:/Users/JBG/Desktop/"+saveFile);

Answer 2

您的操作标记应指向有效的端点servlet / webservice。 看来您将其指向一个jsp文件。 也就是说，在2000年代初就完成了将表示逻辑和服务器端逻辑混合在一起的工作。 在过去的十年中，情况有了很大的改善。 我的建议是看Jersey + Twitter Bootstrap甚至Play来实现您正在做的事情。