<form action="file?file=upload" method="post" enctype="multipart/form-data">
    請(qǐng)選擇你要上傳的文件：<input type="file" name="upload" siez="16"><br>
    <input type="submit" value="提交">
  </form>

//接收上傳文件內(nèi)容中臨時(shí)文件的文件名
        String tempFileName = new String("tempFileName");
        //tempfile 對(duì)象指向臨時(shí)文件
        File tempFile = new File("D:/"+tempFileName);
        //outputfile 文件輸出流指向這個(gè)臨時(shí)文件
        FileOutputStream outputStream = new FileOutputStream(tempFile);
        //得到客服端提交的所有數(shù)據(jù)
        InputStream fileSourcel = request.getInputStream();
        //將得到的客服端數(shù)據(jù)寫入臨時(shí)文件
        byte b[] = new byte[1000];
        int n ;
        while ((n=fileSourcel.read(b))!=-1){
            outputStream.write(b,0,n);
        }

        //關(guān)閉輸出流和輸入流
        outputStream.close();
        fileSourcel.close();

        //randomFile對(duì)象指向臨時(shí)文件
        RandomAccessFile randomFile = new RandomAccessFile(tempFile,"r");
        //讀取臨時(shí)文件的第一行數(shù)據(jù)
        randomFile.readLine();
        //讀取臨時(shí)文件的第二行數(shù)據(jù)，這行數(shù)據(jù)中包含了文件的路徑和文件名
        String filePath = randomFile.readLine();
        //得到文件名
        int position = filePath.lastIndexOf('\\');
        CodeToString codeToString = new CodeToString();
        String filename = codeToString.codeString(filePath.substring(position,filePath.length()-1));
        //重新定位讀取文件指針到文件頭
        randomFile.seek(0);
        //得到第四行回車符的位置，這是上傳文件數(shù)據(jù)的開始位置
        long  forthEnterPosition = 0;
        int forth = 1;
        while((n=randomFile.readByte())!=-1&&(forth<=4)){
            if(n=='\n'){
                forthEnterPosition = randomFile.getFilePointer();
                forth++;
            }
        }

        //生成上傳文件的目錄
        File fileupLoad = new File("D:/work space/JSP workspace/jsp_servlet_upAndLoad/file","upLoad");
        fileupLoad.mkdir();
        //saveFile 對(duì)象指向要保存的文件
        File saveFile = new File("D:/work space/JSP workspace/jsp_servlet_upAndLoad/file/upLoad",filename);
        RandomAccessFile randomAccessFile = new RandomAccessFile(saveFile,"rw");
        //找到上傳文件數(shù)據(jù)的結(jié)束位置，即倒數(shù)第四行
        randomFile.seek(randomFile.length());
        long endPosition = randomFile.getFilePointer();
        int j = 1;
        while((endPosition>=0)&&(j<=4)){
            endPosition--;
            randomFile.seek(endPosition);
            if(randomFile.readByte()=='\n'){
                j++;
            }
        }

        //從上傳文件數(shù)據(jù)的開始位置到結(jié)束位置，把數(shù)據(jù)寫入到要保存的文件中
        randomFile.seek(forthEnterPosition);
        long startPoint = randomFile.getFilePointer();
        while(startPoint<endPosition){
            randomAccessFile.write(randomFile.readByte());
            startPoint = randomFile.getFilePointer();
        }
        //關(guān)閉文件輸入、輸出
        randomAccessFile.close();
        randomFile.close();
        tempFile.delete();

//處理中文字符串的函數(shù)
    public String codeString(String str){
        String s = str;
        try {
            byte[] temp = s.getBytes("utf-8");
            s = new String(temp);
            return s ;
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
            return s;
        }
    }

//獲取要下載的文件名
        String filename = request.getParameter("name");
        //得到想客服端輸出的輸出流
        OutputStream outputStream = response.getOutputStream();
        //輸出文件用的字節(jié)數(shù)組，每次向輸出流發(fā)送600個(gè)字節(jié)
        byte b[] = new byte[600];
        //要下載的文件
        File fileload = new File("D:/work space/JSP workspace/jsp_servlet_upAndLoad/file/upLoad",filename);       
        //客服端使用保存文件的對(duì)話框
        response.setHeader("Content-disposition", "attachment;filename="+filename);
        //通知客服文件的MIME類型
        response.setContentType("application/msword");
        //通知客服文件的長(zhǎng)度
        long fileLength = fileload.length();
        String length = String.valueOf(fileLength);
        response.setHeader("Content_length", length);
        //讀取文件，并發(fā)送給客服端下載
        FileInputStream inputStream = new FileInputStream(fileload);
        int n = 0;
        while((n=inputStream.read(b))!=-1){
            outputStream.write(b,0,n);
        }