checknum.java

openblog是一个博客管理系统

package org.openblog.utils;

import java.io.IOException;


import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;


import javax.servlet.*;
import javax.servlet.http.*;
import java.awt.*;
import java.awt.image.*;
import java.util.*;
import javax.imageio.*;

public class CheckNum extends HttpServlet {

    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        response.setContentType("image/jpeg");
        response.setHeader("Pragma","No-cache");
        response.setHeader("Cache-Control","no-cache");
        response.setDateHeader("Expires", 0);       
        HttpSession session=request.getSession();
        
        int width=60, height=20;
        char[] c ={  '2', '3', '4', '5', '6', '7', '8', '9', 'q',
            'w', 'e', 'r', 't', 'y', 'u', 'i', 'p', 'a', 's', 'd',
            'f', 'g', 'h', 'j', 'k',  'z', 'x', 'c', 'v', 'b', 'n', 'm' };

        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);

       
        Graphics g = image.getGraphics();

       
        Random random = new Random();

        
        g.setColor(getRandColor(200,250));
        g.fillRect(0, 0, width, height);

       
        g.setFont(new Font("Broadway",Font.PLAIN,18));

       
        //g.setColor(new Color());
        //g.drawRect(0,0,width-1,height-1);


        
        g.setColor(getRandColor(160,200));
        for (int i=0;i<155;i++) {
            int x = random.nextInt(width);
            int y = random.nextInt(height);
            int xl = random.nextInt(12);
            int yl = random.nextInt(12);
            g.drawLine(x,y,x+xl,y+yl);
        }

       
        String sRand="";
        for (int i=0;i<4;i++){
            String rand=String.valueOf(c[Math.abs(random.nextInt()) % c.length]);
            sRand+=rand;
            
            g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));//锟斤拷锟矫猴拷锟斤拷锟?4锟斤拷锟斤拷色锟斤拷同锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷为锟斤拷锟斤拷太锟接斤拷锟斤拷锟斤拷只锟斤拷直锟斤拷锟斤拷锟?
            g.drawString(rand,13*i+6,16);
        }

        
        session.setAttribute("checkNum",sRand);
        
        g.dispose();
        ServletOutputStream responseOutputStream =response.getOutputStream();
       
        ImageIO.write(image, "JPEG", responseOutputStream);

        
        responseOutputStream.flush();
        responseOutputStream.close();
    }
    Color getRandColor(int fc,int bc){
        Random random = new Random();
        if(fc>255) fc=255;
        if(bc>255) bc=255;
        int r=fc+random.nextInt(bc-fc);
        int g=fc+random.nextInt(bc-fc);
        int b=fc+random.nextInt(bc-fc);
        return new Color(r,g,b);
    }
    // <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>
}