Java 验证码-oracle sql是什么-程序博客网

[html] view plaincopy

<%@ page language="java" contentType="text/html; charset=utf-8"
pageEncoding="utf-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>验证码</title>
</head>
<body>
<form action="${pageContext.request.contextPath }/servlet/LoginServlet">
<table border="0" cellspacing="0" cellpadding="0" width="50%">
<tr>
<td width="20%" align="right">用户名：</td><td colspan="2"><input type="text" name="username" value="" size="34"/></td>
</tr>
<tr>
<td width="20%" align="right">密码：</td><td colspan="2"><input type="password" name="password" value="" size="35"/></td>
</tr>
<tr>
<td width="20%" align="right">验证码：</td><td width="21%"><input type="text" name="code" value="" size="15"/></td><td align="left"><img src="${pageContext.request.contextPath }/servlet/ImageCodeMakerServlet" width="100px" height="30" /></td>
</tr>
</table>
</form>
</body>
</html>

[html] view plaincopy

<servlet>
<servlet-name>login</servlet-name>
<servlet-class>com.web.LoginServlet</servlet-class>
</servlet>
<servlet>
<servlet-name>imageCodeMakerServlet</servlet-name>
<servlet-class>com.web.ImageCodeMakerServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>login</servlet-name>
<url-pattern>/servlet/LoginServlet</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>imageCodeMakerServlet</servlet-name>
<url-pattern>/servlet/ImageCodeMakerServlet</url-pattern>
</servlet-mapping>

[java] view plaincopy

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
public class LoginServlet extends HttpServlet{
@Override
protected void service(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String username = request.getParameter("username");
String password = request.getParameter("password");
String code = request.getParameter("code");// 页面，用户输入的验证码
HttpSession session = request.getSession();
String randCode = (String)session.getAttribute("randCode");// 得到系统生成的验证码
if(randCode.equals(code)){// 验证码输入正确
System.out.println("验证码输入正确");
}else{
System.out.println("验证码不正确");
}
}
}

[java] view plaincopy

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class ImageCodeMakerServlet extends HttpServlet {
public ImageCodeMakerServlet() {
super();
}
public void destroy() {
super.destroy();
}
public void service(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// 首先设置页面不缓存
response.setHeader("Pragma", "No-cache");
response.setHeader("Cache-Control", "no-cache");
response.setDateHeader("Expires", 0);
// 定义图片的宽度和高度
int width = 90, height = 40;
// 创建一个图像对象
BufferedImage image = new BufferedImage(width, height,
BufferedImage.TYPE_INT_RGB);
// 得到图像的环境对象
Graphics g = image.createGraphics();
Random random = new Random();
// 用随机颜色填充图像背景
g.setColor(getRandColor(180, 250));
g.fillRect(0, 0, width, height);
for (int i = 0; i < 5; i++) {
g.setColor(getRandColor(50, 100));
int x = random.nextInt(width);
int y = random.nextInt(height);
g.drawOval(x, y, 4, 4);
}
// 设置字体，下面准备画随机数
g.setFont(new Font("", Font.PLAIN, 40));
// 随机数字符串
String sRand = "";
for (int i = 0; i < 4; i++) {
// 生成四个数字字符
String rand = String.valueOf(random.nextInt(10));
sRand += rand;
// 生成随机颜色
g.setColor(new Color(20 + random.nextInt(80), 20 + random
.nextInt(100), 20 + random.nextInt(90)));
// 将随机数字画在图像上
g.drawString(rand, (17 + random.nextInt(3)) * i + 8, 34);
// 生成干扰线
for (int k = 0; k < 12; k++) {
int x = random.nextInt(width);
int y = random.nextInt(height);
int xl = random.nextInt(9);
int yl = random.nextInt(9);
g.drawLine(x, y, x + xl, y + yl);
}
}
// 将生成的随机数字字符串写入Session
request.getSession(false).setAttribute("randcode", sRand);
// 使图像生效
g.dispose();
// 输出图像到页面
ImageIO.write(image, "JPEG", response.getOutputStream());
}
/**
* Initialization of the servlet. <br>
*
* @throws ServletException
* if an error occurs
*/
public void init() throws ServletException {
// Put your code here
}
/**
* 产生一个随机的颜色
*
* @param fc
* 颜色分量最小值
* @param bc
* 颜色分量最大值
* @return
*/
public Color getRandColor(int fc, int bc) {
Random random = new Random();
if (fc > 255){
fc = 255;
}
if (bc > 255){
bc = 255;
}
int r = fc + random.nextInt(bc - fc);
int g = fc + random.nextInt(bc - fc);
int b = fc + random.nextInt(bc - fc);
return new Color(r, g, b);
}
}