validatecode.java

网上商城代码

package com.fendou.servlet;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;

import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;


public class ValidateCode extends HttpServlet {
	
	private int width=60;
	private int height=20;
	private static Random rand=new Random();
	
	public ValidateCode() {
		super();
	}
	
	public void destroy() {
		super.destroy(); 
	}
	
	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		
        BufferedImage buffer=new BufferedImage(width,height,BufferedImage.TYPE_INT_BGR);
        Graphics2D g=buffer.createGraphics();
		g.setColor(Color.WHITE);
		g.fillRect(0, 0, width-1, height-1);
		g.setColor(Color.GRAY);
		for(int i=0;i<160;i++){
			int x=rand.nextInt(width);
			int y=rand.nextInt(height);
			int x1=rand.nextInt(12);
			int y1=rand.nextInt(12);
			g.drawLine(x, y, x+x1, y+y1);
		}
		StringBuffer randCode=new StringBuffer();
		Font font=new Font("Times New Roman",Font.BOLD,16);
		for(int i=0;i<4;i++){
			String str=String.valueOf(this.getChar());
			g.setColor(new Color(rand.nextInt(110),rand.nextInt(50),rand.nextInt(50)));
			g.setFont(font);
			g.drawString(str, 13*i+6, 16);
			randCode.append(str);
		}
		HttpSession session=request.getSession();
		session.setAttribute("validCode", randCode.toString());
		response.setHeader("Cache-Contorl", "no-cache");
		response.setDateHeader("Expires", 0);
		response.setContentType("image/jpeg");
		ServletOutputStream out=response.getOutputStream();
		ImageIO.write(buffer,"jpeg",out);
		out.close();
	}

	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		doGet(request,response);
	}

	public void init() throws ServletException {
		
	}
	public  char getChar(){
        return (char)(65+rand.nextInt(26)); 
    }
	
}