登录图片验证码

加用java实现图片验证码

response.setHeader("Pragma", "No-cache");
		response.setHeader("Cache-Control", "No-cache");
		response.setDateHeader("Expires", 0);
		//注意这里输出的是图片
		response.setContentType("image/gif");

		int width = 100;
		int height = 40;
		
		BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
		Graphics g = image.getGraphics();
		Font font = new Font("宋体",Font.BOLD,25);
		g.setFont(font);

		String imagePath = request.getServletContext().getRealPath("/img/11942.jpg"); 
		Image image1 = ImageIO.read(new File(imagePath));
		g.drawImage(image1, 0, 0, 100, 40, null);

		//g.fillRect(0, 0, width, height);
		String source = "0123456789qwertyuiopASDFGHJKL";
		String infor  = "";
		for (int i = 0; i < 4; i++) {

			int index =  new Random().nextInt(source.length()-1);
			char myCode = source.charAt(index);
			Random random = new Random();
			g.setColor(new Color(20+random.nextInt(120),20+random.nextInt(120),20+random.nextInt(120)));
			g.drawString(myCode+"", 15+i*20, 20+new Random().nextInt(10));
			g.drawLine(random.nextInt(100), random.nextInt(40), random.nextInt(100), random.nextInt(40));
			infor += myCode;//记录到后台，以备将来匹配s

		}
		request.getSession().setAttribute("infor", infor);
		
		System.out.println(infor);
		
		
		g.dispose();
		OutputStream out  = response.getOutputStream();
		ImageIO.write(image,"gif", out);
		out.flush();
		out.close();
	}