public class AuthImg extends HttpServlet {
/**
*
*/
private static final long serialVersionUID = 4975974534946437434L;
// 设置图形验证码字符串的字体和大小
private Font mFont = new Font("微软雅黑", Font.ITALIC, 18);
private Random random = new Random();
public void init() throws ServletException {
super.init();
}
// 生成服务器响应的Service方法
public void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// 阻止生成的页面被缓存，保证每次都生成新的验证码
response.setHeader("Pragma", "No-cache");
response.setHeader("Cache-Control", "no-cache");
response.setDateHeader("Expires", 0);
response.setContentType("image/jpeg");
// 指定验证码图片的大小
int width = 80, height = 24;
// 生成一张新的图片
BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_3BYTE_BGR);
// 在图片中绘制内容
Graphics g = image.getGraphics();
g.setColor(new Color(252, 252, 252));
g.fillRect(1, 1, width, height);
g.setColor(new Color(252, 252, 252));
g.drawRect(0, 0, width, height);
g.setFont(mFont);
g.setColor(new Color(252, 252, 252));
// 该变量用于保存系统生成的随机变量字符串
String sRand = "";
int colorR = random.nextInt(200);
int colorG = random.nextInt(200);
int colorB = random.nextInt(200);
for (int i = 0; i < 4; i++) {
// 取得一个随机字符串
String tmp = getRandomChar();
sRand += tmp;
// 将系统生成的随机字符串添加到图片上
g.setColor(new Color(colorR, colorG, colorB));
g.drawString(tmp, 15 * i + 10, 20);
}
// 取得用户的Session
HttpSession session = request.getSession(true);
// 将系统生成的随机验证码添加到用户Session中
session.setAttribute("rand", sRand);
g.dispose();
// 输出验证码图片
ImageIO.write(image, "JPEG", response.getOutputStream());
}
// 生成随机字符串的方法
private String getRandomChar() {
int itmp = random.nextInt(10);
return String.valueOf(itmp);
}
}
java生成验证码图片,布布扣,bubuko.com
java生成验证码图片
原文：http://blog.csdn.net/wuyongde_0922/article/details/38562557
