在JSP+JAVA+XML+HTML下写的WEB图片验证码

核心代码:以下代码使用时请自行调配好路径。

HTML|：<form method="POST" action="LoginCheck">
                  <input type="text" name="random" maxlength="4">
                     <img src="ImageCheckCode">
                 <input type="submit" value="提交"></td>
               </form>

XML|: <servlet-class>fengyan.efly.CreateImageCheckCode</servlet-class>
    </servlet>
    <servlet>
        <servlet-name>LoginCheckServlet</servlet-name>
        <servlet-class>fengyan.efly.LoginCheckServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>CreateImageCheckCode</servlet-name>
        <url-pattern>/ImageCheckCode</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>LoginCheckServlet</servlet-name>
        <url-pattern>/LoginCheck</url-pattern>
    </servlet-mapping>
    <session-config>
        <session-timeout>
            30
        </session-timeout>
    </session-config>
    <welcome-file-list>
        <welcome-file>index.html</welcome-file>
        </welcome-file-list>

JAVA|:

//LoginCheckServlet.java

package fengyan.efly;

import java.io.*;
import java.net.*;

import javax.servlet.*;
import javax.servlet.http.*;

public class LoginCheckServlet extends HttpServlet {

    protected void processRequest(HttpServletRequest req, HttpServletResponse resp)
    throws ServletException, IOException {
     
        HttpSession session=req.getSession();
        String randomCode=(String)session.getAttribute("randomCode");
        if(null==randomCode)
        {
            resp.sendRedirect("login.html");
            return;
        }       
        String reqRandom=req.getParameter("random");       
        req.setCharacterEncoding("GBK");
        resp.setContentType("text/html;charset=GBK");
        PrintWriter out=resp.getWriter();       
        if(randomCode.equals(reqRandom))
        {           
            out.println("验证码匹配！");
        }
        else
        {
            out.println("验证码校验失败，请单击浏览器上的后退!");
        }
        out.close();
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        processRequest(request, response);
    }

    protected void doPost(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        processRequest(request, response);
    }

    public String getServletInfo() {
        return "Short description";
    }
}

//CreateImageCheckCode.java

package fengyan.efly;
import java.io.*;
import java.net.*;

import javax.servlet.*;
import javax.servlet.http.*;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.util.Random;
import javax.imageio.ImageIO;

public class CreateImageCheckCode extends HttpServlet {   
    //验证码图片的宽度。
    private int width=60;
    //验证码图片的高度。
    private int height=20;
   
    protected void processRequest(HttpServletRequest req, HttpServletResponse resp)
    throws ServletException, IOException {
        resp.setContentType("text/html;charset=UTF-8");
        BufferedImage buffImg=new BufferedImage(width,height,
                                                BufferedImage.TYPE_INT_RGB);
        Graphics2D g=buffImg.createGraphics();
       
        //创建一个随机数生成器类。
        Random random=new Random();
       
        g.setColor(Color.WHITE);
        g.fillRect(0,0,width,height);
       
        //创建字体，字体的大小应该根据图片的高度来定。
        Font font=new Font("Times New Roman",Font.PLAIN,18);
        //设置字体。
        g.setFont(font);
       
        //画边框。
        g.setColor(Color.BLACK);
        g.drawRect(0,0,width-1,height-1);
       
        //随机产生160条干扰线，使图象中的认证码不易被其它程序探测到。
        g.setColor(Color.GRAY);
        for (int i=0;i<160;i++)
        {
            int x = random.nextInt(width);
            int y = random.nextInt(height);
            int xl = random.nextInt(12);
            int yl = random.nextInt(12);
            g.drawLine(x,y,x+xl,y+yl);
        }       
        //randomCode用于保存随机产生的验证码，以便用户登录后进行验证。
        StringBuffer randomCode=new StringBuffer();
        int red=0,green=0,blue=0;
       
        //随机产生4位数字的验证码。
        for (int i=0;i<4;i++)
        {
            //得到随机产生的验证码数字。
            String strRand=String.valueOf(random.nextInt(10));
           
            //产生随机的颜色分量来构造颜色值，这样输出的每位数字的颜色值都将不同。
            red=random.nextInt(110);
            green=random.nextInt(50);
            blue=random.nextInt(50);
           
            //用随机产生的颜色将验证码绘制到图像中。
            g.setColor(new Color(red,green,blue));
            g.drawString(strRand,13*i+6,16);
           
            //将产生的四个随机数组合在一起。
            randomCode.append(strRand);
        }
        //将四位数字的验证码保存到Session中。
        HttpSession session=req.getSession();
        session.setAttribute("randomCode",randomCode.toString());
       
        //禁止图像缓存。
        resp.setHeader("Pragma","no-cache");
        resp.setHeader("Cache-Control","no-cache");
        resp.setDateHeader("Expires", 0);       
        resp.setContentType("image/jpeg");
       
        //将图像输出到Servlet输出流中。
        ServletOutputStream sos=resp.getOutputStream();
        ImageIO.write(buffImg, "jpeg",sos);
        sos.close();
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        processRequest(request, response);
    }

    protected void doPost(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        processRequest(request, response);
    }

    public String getServletInfo() {
        return "Short description";
    }
}