servlet實現從oracle數據庫的blob字段中讀出文件並顯示

　　/*
* ReadFilejava
*
* Created on 年月日下午:
*/

　　package jgwlapp;

　　import javaio*;
import *;

　　import javaxservlet*;
import javaxservlethttp*;
import javasql*;
import jgwlbaseDataBaseConnection;
import javaio*;
import oraclesql*;

　　/**
*
* @author Roy Chen
* @version
*/
public class ReadFile extends HttpServlet {

    /** Initializes the servlet
     */
    public void init(ServletConfig config) throws ServletException {
        superinit(config);

    }

    /** Destroys the servlet
     */
    public void destroy() {

    }

    /** Processes requests for both HTTP <code>GET</code> and <code>POST</code> methods
     * @param request servlet request
     * @param response servlet response
     */
    protected void processRequest(HttpServletRequest request HttpServletResponse response)
    throws ServletException IOException {

        byte[] buf=new byte[];
        try{
            Statement stmt=new DataBaseConnection()getStatement();
            ResultSet rs=stmtexecuteQuery(select * from demo where id=);
            responsereset();
            //responsesetHeader(ContentDisposition attachement;filename=ssdoc;);
            //**如要浏覽器直接另存為就不屏蔽上行filename 為文件名
            responsesetContentType(application/msword;charset=GBK);
            //**此處為文件的mime類型可以在網上搜到本例為word
            //application/vndmsexcel;charset=GBK 表示excel文件類型
           //application/vndpdf;charset=GBK           表示pdf文件類型

　　ServletOutputStream out=responsegetOutputStream();
           InputStream in;
           if(rsnext())
             in = blobgetBinaryStream();
            while(inread(buf)!=){
                outwrite(buf);
            }

            outflush();
            outclose();
           //**以下為網上看到的寫如文件的樣例
           //==================
            // while(rsnext()) {
            //ServletOutputStream sout = responsegetOutputStream();
            //InputStream in = rsgetBinaryStream();
            //byte b[] = new byte[xa];
            //for(int i = inread(b); i != ;){
            // soutwrite(b);
            // inread(b);
            // }
            // soutflush();
            // soutclose();
            //}

            //====================
            //FileOutputStream file_out=new FileOutputStream(f:\filename);

            //InputStream blob_in=blobgetBinaryStream();
            //int temp;
            // while((temp=blob_inread())!=){
            // file_outwrite(temp);}
            // blob_inclose();
            // file_outclose();
            //outwrite(blobgetBinaryStream());
            //outflush();
            stmtclose();
        }catch (SQLException e){
            eprintStackTrace();
        }
        //PrintWriter out = responsegetWriter();
        /* TODO output your page here
        outprintln(<html>);
        outprintln(<head>);
        outprintln(<title>Servlet</title>);
        outprintln(</head>);
        outprintln(<body>);

        outprintln(</body>);
        outprintln(</html>);
         */
        //outclose();
    }

    /** Handles the HTTP <code>GET</code> method
     * @param request servlet request
     * @param response servlet response
     */
    protected void doGet(HttpServletRequest request HttpServletResponse response)
    throws ServletException IOException {
        processRequest(request response);
    }

    /** Handles the HTTP <code>POST</code> method
     * @param request servlet request
     * @param response servlet response
     */
    protected void doPost(HttpServletRequest request HttpServletResponse response)
    throws ServletException IOException {
        processRequest(request response);
    }

    /** Returns a short description of the servlet
     */
    public String getServletInfo() {
        return Short description;
    }

}

From:http://tw.wingwit.com/Article/program/Oracle/201311/17924.html