package servlet;

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

import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
@WebServlet("/servletImage")
public class servletImage extends HttpServlet {

    public servletImage() {
        super();
    }
    public void destroy() {
        super.destroy();
    }
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
    	response.setHeader("Expires", "-1");
		response.setHeader("Cache-Control", "no-cache");
		response.setHeader("Pragma", "no-cache");
		
 
		int width = 120;
		int height = 25;
		//创建一副内存图像：BufferedImage
		BufferedImage image = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);
		//得到属于该图片的画笔：Graphics
		Graphics g = image.getGraphics();
			//画边框
		g.setColor(Color.BLUE);
		g.drawRect(0, 0, width, height);
			//填充背景色
		g.setColor(Color.YELLOW);
		g.fillRect(1, 1, width-2, height-2);
			//画干扰线
		g.setColor(Color.GRAY);
		
		Random r = new Random();
		for(int i=0;i<10;i++)
			g.drawLine(r.nextInt(width), r.nextInt(height), r.nextInt(width), r.nextInt(height));
		
			//随机数字
		g.setColor(Color.RED);
		g.setFont(new Font("宋体", Font.BOLD|Font.ITALIC, 20));
		int x = 23;
		StringBuffer sb = new StringBuffer();
		for(int i=0;i<4;i++){
			String checkcode = r.nextInt(10)+"";
			sb.append(checkcode);
			
			g.drawString(checkcode, x, 20);
			x+=20;
		}
		System.out.println(sb.toString());
		//把验证码放到HttpSession中
		request.getSession().setAttribute("checkcode", sb.toString());
		ImageIO.write(image, "jpg", response.getOutputStream());
    }

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

    }


}