servlet注册码

来源：互联网发布：兄弟加工中心编程编辑：程序博客网时间：2024/05/23 12:25

index.jsp

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
    <base href="<%=basePath%>">

    <title>My JSP 'index.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">

<script type="text/javascript">
  function show(obj)
  {
   //alert(obj.src);
   obj.src = "tt?a="+Math.random();
   //alert(obj.src);
  }
</script>
</head>

<body>
    <form name="form1" method="post" action="bb">
    验证码：
      <input name="randCode" type="text"/>
      <img alt="sss" src="tt" height="25" width="60" onclick="show(this);"/>
     <input name="submit" type="submit" value="submit" />
</form>
</body>
</html>

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4"
xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">

<servlet>
  <servlet-name>tt</servlet-name>
  <servlet-class>com.test.Test</servlet-class>
</servlet>
<servlet-mapping>
  <servlet-name>tt</servlet-name>
  <url-pattern>/tt</url-pattern>
</servlet-mapping>

<servlet>
  <servlet-name>bb</servlet-name>
  <servlet-class>com.test.Ceshi</servlet-class>
</servlet>
<servlet-mapping>
  <servlet-name>bb</servlet-name>
  <url-pattern>/bb</url-pattern>
</servlet-mapping>

<welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>

Ceshi .java

package com.test;

import java.io.IOException;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class Ceshi extends HttpServlet{
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
   throws ServletException, IOException {
   doPost(req, resp);
}

@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp)
   throws ServletException, IOException {
  System.out.println("bbbb");
        ServletContext context = getServletContext();

        //获得当前session中的验证码
        Object codeCurrent = context.getAttribute("randomNum");

        //获得用户输入的验证码
        String codeInput = req.getParameter("randCode");

        if (codeInput.equals(codeCurrent)) {
        resp.sendRedirect("same.jsp");
        } else {
        resp.sendRedirect("different.jsp");
        }
}
}

Test.java

package com.test;

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.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class Test extends HttpServlet{
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
   throws ServletException, IOException {
   doPost(req, resp);
}

@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp)
   throws ServletException, IOException {
   //首先设置页面不缓存
        resp.setHeader("Pragma", "No-cache");
        resp.setHeader("Cache-Control", "no-cache");
        resp.setDateHeader("Expires", 0);

        //定义图片的宽度和高度
        int width = 90, height = 40;

        //创建一个图形对象
        BufferedImage image = new BufferedImage(width, height,
                                                BufferedImage.TYPE_INT_BGR);

        //得到图像的环境对象
        Graphics g = image.createGraphics();

        //用随机颜色填充图形背景
        Random random = new Random();
        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 Font(String name, int style, int size)
        g.setFont(new Font("", Font.PLAIN,40));

        String sRand = ""; //随机字符串
        //生成四个随机字符
        for (int i = 0; i < 4; i++) {
            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 j = 0; j < 12; j++) {
                int x = random.nextInt(width);
                int y = random.nextInt(height);
                int x1 = random.nextInt(9);
                int y1 = random.nextInt(9);
                g.drawLine(x, y, x + x1, y + y1);
            }
        }

        ServletContext context = getServletContext();
        context.setAttribute("randomNum", sRand);

        //将生成的随机字符串写入session
        req.getSession().setAttribute("randCode", sRand);

        //使图像生效
        g.dispose();

        //输出图像到页面
        ImageIO.write(image, "jpeg", resp.getOutputStream());
    }

public Color getRandColor (int fc, int bc){
    Random random = new Random();

    if (fc > 255) {
        fc = 255;
    }
    if (bc > 255) {
        bc = 255;
    }

    int red = fc + random.nextInt(bc - fc);
    int green = fc + random.nextInt(bc - fc);
    int blue = fc + random.nextInt(bc - fc);
    return new Color(red, green, blue);
}
}