以前积攒的一个验证码

一个Java类：

package com.abc.ufo.util;



import java.awt.Color;

import java.awt.Font;

import java.awt.Graphics;

import java.awt.image.BufferedImage;

import java.io.OutputStream;

import java.util.Random;



import javax.imageio.ImageIO;







public class ImageMaker{

    private char map[]={'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','1','2','3','4','5','6','7','8','9'};



    public String getImage(int width,int height,OutputStream os){

        BufferedImage image=new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);

        

        Graphics g=image.getGraphics();

        g.setColor(new Color(0xDCDCDC));

        g.fillRect(0, 0, width, height);

        

        

        

        StringBuilder sb=new StringBuilder();

        for(int i=0;i<4;i++){

            sb.append(map[(int)(map.length*Math.random())]);

        }

        String text=sb.toString();

        

        g.setColor(Color.black);

        g.setFont(new Font("Arial",Font.PLAIN,36));

        

        g.setColor(Color.red);

        String str=text.substring(0,1);

        g.drawString(str, 18, 32);

        

        g.setColor(Color.blue);

        str=text.substring(1,2);

        g.drawString(str, 60, 32);

        

        g.setColor(Color.red);

        str=text.substring(2,3);

        g.drawString(str, 95, 32);

        

        g.setColor(Color.blue);

        str=text.substring(3,4);

        g.drawString(str, 125, 32);

        

        g.setColor(Color.gray);

        Random rand=new Random();

        for(int i=0;i<20;i++){

            int x=rand.nextInt(width);

            int y=rand.nextInt(height);

            g.drawOval(x, y, width, height);

        }

        

        g.setColor(Color.black);

        g.drawRect(0, 0, width-1, height-1);

        //g.drawLine(width-2, 0, width-2, height);

        

        g.dispose();

        

        try{

            ImageIO.write(image, "JPEG", os);

        }catch(Exception e){

            //e.printStackTrace();

        }

        

        return text;

    }

}

JSP：

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>

<%@ page contentType="image/jpeg" %>

<jsp:useBean id="image" scope="page" class="com.abc.ufo.util.ImageMaker"/>



<%

    String str=image.getImage(160,40,response.getOutputStream());

    session.setAttribute("verifyCode",str);

    out.clear();  

    out = pageContext.pushBody(); 

%>

页面使用：

<div class="page-container">

            <logic:present name="error">

                 <h2><bean:write name="error"/></h2>

            </logic:present>

                        

            <h1>Login</h1>

            <form action="login.html" method="post">

                <input type="text" id="usernameTxt" name="username" class="username" placeholder="Username">

                <input type="password" id="passwordTxt" name="password" class="password" placeholder="Password">

                <input type="text" id="verifyCodeTxt" name="verifyCode" class="verifyCode" placeholder="Verification code">

                <p><br/>No Zero in the verification code</p>

                <img src="pages/user/login/image.jsp"/> <!-- 这个路径就是前面jsp的路径 -->

                <button id="submitBtn">Sign me in</button>

                <div class="error"><span>+</span></div>

            </form>

            <div class="connect" style="display:none">

                <p>Or connect with:</p>

                <p>

                    <a class="facebook" href=""></a>

                    <a class="twitter" href=""></a>

                </p>

            </div>

        </div>

页面效果：