neh*_*oni 1 java jsp file-upload
我想通过使用下面给出的代码上传pdf文件.它提供浏览设施,但不上传文件.当我点击sendfile按钮时,显示uploadfile.html代码页.我怎样才能做到这一点？？？给定代码中的错误在哪里???
文件名,upload.html
<%@ page language="java" %>
<HTml>
<HEAD><TITLE>Display file upload form to the user</TITLE></HEAD>
<% // for uploading the file we used Encrypt type of multipart/
form-data and input of file type to browse and submit the file %>
<BODY> <FORM ENCTYPE="multipart/form-data" ACTION=
"uploadfile.html" METHOD=POST>
<br><br><br>
<center><table border="2" >
<tr><center><td colspan="2"><p align=
"center"><B>PROGRAM FOR UPLOADING THE FILE</B><center></td></tr>
<tr><td><b>Choose the file To Upload:</b>
</td>
<td><INPUT NAME="F1" TYPE="file"></td></tr>
<tr><td colspan="2">
<p align="right"><INPUT TYPE="submit" VALUE="Send File" ></p></td></tr>
<table>
</center>
</FORM>
</BODY>
</HTML>
文件名 - uploadfile.html
<%@ page import="java.io.*" %>
<%
//to get the content type information from JSP Request Header
String contentType = request.getContentType();
//here we are checking the content type is not equal to Null and
as well as the passed data from mulitpart/form-data is greater than or
equal to 0
if ((contentType != null) && (contentType.indexOf("multipart/
form-data") >= 0)) {
DataInputStream in = new DataInputStream(request.
getInputStream());
//we are taking the length of Content type data
int formDataLength = request.getContentLength();
byte dataBytes[] = new byte[formDataLength];
int byteRead = 0;
int totalBytesRead = 0;
//this loop converting the uploaded file into byte code
while (totalBytesRead < formDataLength) {
byteRead = in.read(dataBytes, totalBytesRead,
formDataLength);
totalBytesRead += byteRead;
}
String file = new String(dataBytes);
//for saving the file name
String 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;
//extracting the index of file
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;
// creating a new file with the same name and writing the
content in new file
FileOutputStream fileOut = new FileOutputStream(saveFile);
fileOut.write(dataBytes, startPos, (endPos - startPos));
fileOut.flush();
fileOut.close();
%><Br><table border="2"><tr><td><b>You have successfully
upload the file by the name of:</b>
<% out.println(saveFile); %></td></tr></table> <%
}
%>
Bal*_*usC 38
这显然是Roseindia的代码片段.首先,它是有史以来最糟糕的学习资源.不要使用它.它只教导不良做法.将该网站添加到您的黑名单.事实上,任何充满广告横幅和绝望过时的低质量代码片段的"教程"网站都由业余爱好者清楚地保留,主要关注广告收入而不是严肃的教学.这种废话"教程"网站的其他例子是javabeat,tutorialspoint,journaldev,javatpoint等.这些网站的常见之处在于它们起源于印度.
除了您错误地使用.html文件扩展名而不是.jsp(尽管他们使用.jsp扩展名正确地展示了他们的示例)之外,代码片段还存在以下几个主要问题:
<font>,并<center>自1998年以来,其已被弃用的标签.Content-Length请求标头,该标头本身并不总是存在.如果没有此标头,则代码会中断.String使用服务器平台默认字符编码而不是多部分头中指定的编码来创建基于字节数组的字节数.这可能会导致结果字节错误/损坏.DataInputStream包装是不必要的,代码没有服用任何好处.这太可怕了.
从JSP上传文件的正确方法是将表单提交给带@MultipartConfig注释的servlet类,然后使用它request.getPart()来获取文件.您可以在这个答案中找到一个片段:如何使用JSP/Servlet将文件上传到服务器？
在这个答案中详细阐述了学习Java EE的正确方法:Java EE Web开发,我从哪里开始,我需要什么技能？
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