用javaweb随机验证码登录的程序
时间: 2024-05-11 18:14:43 浏览: 5
以下是一个用JavaWeb实现随机验证码登录的示例程序:
1. 在JSP页面中添加验证码输入框和验证码图片
```jsp
<form action="loginServlet" method="post">
<label>用户名:</label>
<input type="text" name="username" /><br />
<label>密码:</label>
<input type="password" name="password" /><br />
<label>验证码:</label>
<input type="text" name="verifyCode" /><br />
<img src="verifyCodeServlet" alt="验证码" />
<input type="submit" value="登录" />
</form>
```
2. 创建生成验证码的Servlet
```java
public class VerifyCodeServlet extends HttpServlet {
private static final String VERIFY_CODES = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
private static Random random = new Random();
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// 设置响应头信息
response.setContentType("image/jpeg");
response.setHeader("Pragma", "No-cache");
response.setHeader("Cache-Control", "no-cache");
response.setDateHeader("Expires", 0);
// 生成验证码图片
int width = 100, height = 30;
BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
Graphics g = image.getGraphics();
g.setColor(Color.WHITE);
g.fillRect(0, 0, width, height);
StringBuilder verifyCode = new StringBuilder();
for (int i = 0; i < 4; i++) {
verifyCode.append(VERIFY_CODES.charAt(random.nextInt(VERIFY_CODES.length())));
}
g.setColor(Color.BLACK);
Font font = new Font("Arial", Font.BOLD, 20);
g.setFont(font);
g.drawString(verifyCode.toString(), 5, 20);
g.dispose();
// 将验证码保存到Session中
HttpSession session = request.getSession();
session.setAttribute("verifyCode", verifyCode.toString());
// 将验证码图片输出到客户端
ImageIO.write(image, "JPEG", response.getOutputStream());
}
}
```
3. 创建登录验证的Servlet
```java
public class LoginServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// 获取用户输入的信息和验证码
String username = request.getParameter("username");
String password = request.getParameter("password");
String verifyCode = request.getParameter("verifyCode");
// 获取Session中保存的验证码
HttpSession session = request.getSession();
String sessionVerifyCode = (String) session.getAttribute("verifyCode");
// 验证验证码是否正确
if (!verifyCode.equalsIgnoreCase(sessionVerifyCode)) {
request.setAttribute("message", "验证码错误");
request.getRequestDispatcher("/login.jsp").forward(request, response);
} else {
// 验证用户名和密码是否正确
if (username.equals("admin") && password.equals("123456")) {
request.setAttribute("message", "登录成功");
request.getRequestDispatcher("/success.jsp").forward(request, response);
} else {
request.setAttribute("message", "用户名或密码错误");
request.getRequestDispatcher("/login.jsp").forward(request, response);
}
}
}
}
```
4. 创建登录成功页面和登录页面
```jsp
<!-- success.jsp -->
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>登录成功</title>
</head>
<body>
<h1>${message}</h1>
</body>
</html>
```
```jsp
<!-- login.jsp -->
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>登录页面</title>
</head>
<body>
<h1>${message}</h1>
<form action="loginServlet" method="post">
<label>用户名:</label>
<input type="text" name="username" /><br />
<label>密码:</label>
<input type="password" name="password" /><br />
<label>验证码:</label>
<input type="text" name="verifyCode" /><br />
<img src="verifyCodeServlet" alt="验证码" />
<input type="submit" value="登录" />
</form>
</body>
</html>
```
5. 配置Web.xml文件
```xml
<servlet>
<servlet-name>loginServlet</servlet-name>
<servlet-class>com.example.LoginServlet</servlet-class>
</servlet>
<servlet>
<servlet-name>verifyCodeServlet</servlet-name>
<servlet-class>com.example.VerifyCodeServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>loginServlet</servlet-name>
<url-pattern>/loginServlet</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>verifyCodeServlet</servlet-name>
<url-pattern>/verifyCodeServlet</url-pattern>
</servlet-mapping>
```
以上就是一个用JavaWeb实现随机验证码登录的示例程序。