使用Servlet實現上傳檔案功能

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1.servlet只需加上一個注釋和用request.getPart來擷取檔案的值，這是servlet3.0的API

2.表單需要加上一個屬性enctype="multipart/form-data"

 

現在附上代碼

表單：

 <form method="POST" action="upload" enctype="multipart/form-data" >            File:            <input type="file" name="file" id="file" /> <br/>            Destination:            <input type="text" value="f:" name="destination"/>            <br/>            <input type="submit" value="Upload" name="upload" id="upload" />
</form>

 

servlet：

在類的聲名上加上這兩個注釋

@WebServlet(name = "FileUploadServlet", urlPatterns = {"/upload"})
@MultipartConfig

自訂的方法：

processRequest方法是擷取檔案的值的

protected void processRequest(HttpServletRequest request,            HttpServletResponse response)            throws ServletException, IOException {        response.setContentType("text/html;charset=UTF-8");
　　　　　　request.setCharacterEncoding("utf-8");
　　　　　　
　　　　　//擷取路徑        final String path = request.getParameter("destination");
　　　　　//擷取檔案的值        final Part filePart = request.getPart("file");        System.out.println(filePart);        final String fileName = getFileName(filePart);　　　　　//使用IO流對檔案進行操作        OutputStream out = null;        InputStream filecontent = null;        final PrintWriter writer = response.getWriter();        try {            out = new FileOutputStream(new File(path + File.separator                    + fileName));            filecontent = filePart.getInputStream();            int read;            final byte[] bytes = new byte[1024];            while ((read = filecontent.read(bytes)) != -1) {                out.write(bytes, 0, read);            }            writer.println("New file " + fileName + " created at " + path);            LOGGER.log(Level.INFO, "File {0} being uploaded to {1}",                    new Object[]{fileName, path});        } catch (FileNotFoundException fne) {            writer.println("You either did not specify a file to upload or are "                    + "trying to upload a file to a protected or nonexistent "                    + "location.");            writer.println("<br/> ERROR: " + fne.getMessage());            LOGGER.log(Level.SEVERE, "Problems during file upload. Error: {0}",                    new Object[]{fne.getMessage()});        } finally {            if (out != null) {                out.close();            }            if (filecontent != null) {                filecontent.close();            }            if (writer != null) {                writer.close();            }        }    }

 

getFileName方法是擷取檔案名稱的

private String getFileName(final Part part) {final String partHeader = part.getHeader("content-disposition");LOGGER.log(Level.INFO, "Part Header = {0}", partHeader);for (String content : part.getHeader("content-disposition").split(";")) {if (content.trim().startsWith("filename")) {return content.substring(content.indexOf(‘=‘) + 1).trim().replace("\"", "");}}return null;}

 

最後在doPost方法裡寫

protected void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {processRequest(request, response);}

到這裡就全部完成了，長傳成功的效果，

 

使用Servlet實現上傳檔案功能