第一个jsp的验证码

最新推荐文章于 2025-08-12 02:34:52 发布

原创最新推荐文章于 2025-08-12 02:34:52 发布 · 822 阅读

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CC 4.0 BY-SA版权

文章标签：

#jsp #string #random #image #input #list

1，首先创建RandImgCreate类，用于产生验证码。

package com.vogoal.util.img;

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.http.HttpServletResponse;

/**
* @author SinNeR
* http://bbs.blueidea.com
* image check creater
*/
public class RandImgCreater {
    private static final String CODE_LIST = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890";
    private HttpServletResponse response = null;
    private static final int HEIGHT = 20;
    private static final int FONT_NUM = 4;
    private int width = 0;
    private int iNum = 0;
    private String codeList = "";
    private boolean drawBgFlag = false;

    private int rBg = 0;
    private int gBg = 0;
    private int bBg = 0;
    public RandImgCreater(HttpServletResponse response) {
        this.response = response;
        this.width = 13 * FONT_NUM + 12;
        this.iNum = FONT_NUM;
        this.codeList = CODE_LIST;
    }

    public RandImgCreater(HttpServletResponse response,int iNum,String codeList) {
        this.response = response;
        this.width = 13 * iNum + 12;
        this.iNum = iNum;
        this.codeList = codeList;
    }

    public String createRandImage(){
        BufferedImage image = new BufferedImage(width, HEIGHT,
                BufferedImage.TYPE_INT_RGB);

        Graphics g = image.getGraphics();

        Random random = new Random();

        if ( drawBgFlag ){
            g.setColor(new Color(rBg,gBg,bBg));
            g.fillRect(0, 0, width, HEIGHT);
        }else{
            g.setColor(getRandColor(200, 250));
            g.fillRect(0, 0, width, HEIGHT);

            for (int i = 0; i < 155; i++) {
                g.setColor(getRandColor(140, 200));
                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);
            }
        }

        g.setFont(new Font("Times New Roman", Font.PLAIN, 18));

        String sRand="";
        for (int i=0;i<iNum;i++){
            int rand=random.nextInt(codeList.length());
            String strRand=codeList.substring(rand,rand+1);
            sRand+=strRand;
            g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));
            g.drawString(strRand,13*i+6,16);
        }

        g.dispose();

        try{
            ImageIO.write(image, "JPEG", response.getOutputStream());
        }catch(IOException e){

        }

        return sRand;
    }

    public void setBgColor(int r,int g,int b){
        drawBgFlag = true;
        this.rBg = r;
        this.gBg = g;
        this.bBg = b;
    }

    private 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);
    }
}

2，建立一个img.jsp文件，用来建立RandImgCreate对象，产生随机码，并将随机码放入session中。

<%@ page contentType="image/jpeg" import="com.vogoal.util.img.*" %>

<%
response.setHeader("Pragma","No-cache");
response.setHeader("Cache-Control","no-cache");
response.setDateHeader("Expires", 0);

RandImgCreater rc = new RandImgCreater(response);
//RandImgCreater rc = new RandImgCreater(response,8,"abcdef");
//rc.setBgColor(100,100,100);
String rand = rc.createRandImage();
session.setAttribute("rand",rand);
%>

3，建立显示验证码页面，并通过提交到另一页面来验证是否正确！

<form name="frm" method="post" action="chkImg.jsp">
Hello Image Test<br/>
checkCode:<img src="img.jsp"><br/>
please input the checkCode:<input type="text" name="code" value=""><br/>
<input type="submit" name="btn1" value="check">
</form>

在网上找到了一个比较方便的方法来实现验证码的刷新，在img标签中添加“onclick="this.src=this.src+'?'"”.

4，建立chkImg.jsp页面来验证。

<%
String inputCode = request.getParameter("code");
String code = (String)session.getAttribute("rand");
if ( inputCode.equals(code) ){
%>
check SUCCESS!!!!!
<%}else{%>
wrong code!!!!!!!
<%}%>