登录验证码
Servlet
/*
- 从请求中获取数据,获取验证码的session的值转为String类型,
- 销毁,防止返回后验证码不刷新,重新验证成功
- 判断验证码是否相同(忽略大小写)
- 相同:创建user对象调用service层的方法验证返回结果是否为空
* 为空:创建session:储存错误信息,转发,登录页面显示登录名或密码错误
* 不为空:创建session:储存用户名,转发,到登录成功页面 - 不相同:创建session:储存错误信息,登录页面显示验证码错误(判断如果session为null不显示)
public class Servlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
Login login = new service.impl.Login();
String username =request.getParameter("username");
String password = request.getParameter("password");
String code = request.getParameter("code");
Object checkcode1 = request.getSession().getAttribute("checkcode");
String checkcode = (String) checkcode1;
request.getSession().removeAttribute("checkcode");
if (checkcode!=null&&code.equalsIgnoreCase(checkcode)){
User u=new User();
u.setUsername(username);
u.setPassword(password);
User user = login.Login(u);
if (user!=null){ request.getSession().setAttribute("username",username)
request.getRequestDispatcher("Success.jsp").forward(request,response);
}else{ request.getSession().setAttribute("userfail","用户名或密码错误");
request.getRequestDispatcher("index.jsp").forward(request,response);
} }else{ request.getSession().setAttribute("codefail","验证码错误");
request.getRequestDispatcher("index.jsp").forward(request,response);
}
}
CheckcodeServlet
public class CheckcodeServlet extends HttpServlet { protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//定义验证码框的长宽
int width = 100;
int height = 50;
//创建image对象
BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
//创建画笔对象
Graphics graphics = image.getGraphics();
//设置画笔颜色
graphics.setColor(Color.white);
//填充背景
graphics.fillRect(0, 0, width, height);
//重新设定画笔颜色 graphics.setColor(Color.BLUE);
//画验证码的边框
graphics.drawRect(0, 0, width - 1, height - 1);
//将验证码所要显示的内容组成字符串
String s = "QWERTYUIOPASDFGHJKLZXCVBNMqwertyuiopasdfghjklzxcvbnm1234567890";
//创建随机数对象
Random random = new Random();
//创建颜色数组
Color[] colors = {Color.red, Color.BLACK, Color.magenta, Color.YELLOW, Color.GREEN};
//创建builder对象用于组合验证码
StringBuilder builder = new StringBuilder();
//for循环画验证码
for (int i = 1; i <= 4; i++) {
//每个字母换一个颜色 graphics.setColor(colors[new Random().nextInt(colors.length)]);
//随机生成字符串下标
int index = random.nextInt(s.length());
//通过字符串下标拿到字符
char c = s.charAt(index);
//组合字符串
builder.append(c);
//设置验证码的字体
graphics.setFont(new Font("Comic Sans MS", Font.BOLD, 20));
//验证码所要摆放的位置
graphics.drawString(c + "", width / 5 * i, height / 2);
}
//将验证码转为String类型
String s1 = builder.toString();
//存放在session中 request.getSession().setAttribute("checkcode", s1); //for循环画干扰线
for (int i = 0; i < 30; i++) {
//设置干扰线颜色
graphics.setColor(colors[new Random().nextInt(colors.length)]);
//设置干扰线坐标
int x = random.nextInt(width);
int y = random.nextInt(height);
int x1 = random.nextInt(30);
int y1 = random.nextInt(30);
int sin = random.nextBoolean() ? 1 : -1;
int cos = random.nextBoolean() ? 1 : -1; graphics.drawLine(x, y, x + x1 * sin, y + y1 * cos); }
//输出验证码框
ImageIO.write(image, "jpg", response.getOutputStream());
}