showimage.java

介绍了j2ee开发常用的学习知识,如servlet,javamail,EJB等知识,并有项目源码.

/*
 * ShowImage.java
 *
 * Created on 2007年10月25日, 上午10:49
 */

package com.data;

import java.io.*;
import javax.annotation.Resource;
import javax.naming.NamingException;

import javax.servlet.*;
import javax.servlet.http.*;
import javax.sql.DataSource;

/**
 *
 * @author hyl
 * @version
 */
public class ShowImage extends HttpServlet {
    
    @Resource(name = "sample")
    private DataSource sample;
    
    /** 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 {
        java.sql.Connection conn;
        java.lang.String strConn;
        java.sql.Statement Stmt; //语句对象
        java.sql.ResultSet sqlRst; //结果集对象
        ServletOutputStream op = response.getOutputStream();
        //PrintWriter out = response.getWriter();
        //在数据库中的照片的ID
        String photoid ="";
        photoid = request.getParameter("photoid");
        String SQLString = "select * from album where id =" + photoid;
        try{
            
            conn = sample.getConnection();
            Stmt = conn.createStatement(java.sql.ResultSet.TYPE_SCROLL_INSENSITIVE,java.sql.ResultSet.CONCUR_READ_ONLY);
//	执行Sql语句
            sqlRst=Stmt.executeQuery( SQLString);
            while(sqlRst.next()){
                java.sql.Blob blob=sqlRst.getBlob( "data" );
                byte[] ab = blob.getBytes(1, (int)blob.length());
                response.setContentType("image/gif");
                response.reset();
                op.write(ab);
                op.flush();
                op.close();
            }
            Stmt.close();
            conn.close();
        } catch (java.sql.SQLException e){
            e.printStackTrace();
        }catch (Exception e){
            e.printStackTrace();
        }
        
    }
    
    // <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
    /** 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";
    }
    // </editor-fold>
}