生成验证码的几种方式

⽣成验证码的⼏种⽅式

⽣成验证码的⼏种⽅式

1，在jsp页⾯中直接⽣成验证码

image.jsp源码：

//image.jsp

<%@ page contentType="image/jpeg"

import="java.awt.*,java.awt.image.*,java.util.*,javax.imageio.*"

pageEncoding="GBK"%>

<%!Color getRandColor(int fc, int bc) {//给定范围获得随机颜⾊

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);

}%>

<%

//设置页⾯不缓存

response.setHeader("Pragma", "No-cache");

response.setHeader("Cache-Control", "no-cache");

response.setDateHeader("Expires", 0);

// 在内存中创建图象

// 通过这⾥可以修改图⽚⼤⼩

int width = 85, height = 23;

BufferedImage image = new BufferedImage(width, height,

BufferedImage.TYPE_INT_RGB);

// 获取图形上下⽂

// g相当于笔

Graphics g = image.getGraphics();

//⽣成随机类

Random random = new Random();

// 设定背景⾊

g.setColor(getRandColor(200, 250));

// 画⼀个实⼼的长⽅，作为北京

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

//设定字体

g.setFont(new Font("⿊体", Font.PLAIN, 18));

//画边框

g.setColor(Color.BLUE);

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

// 随机产⽣155条⼲扰线，使图象中的认证码不易被其它程序探测到

g.setColor(getRandColor(160, 200));

for (int i = 0; i < 155; 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);

}

// 取随机产⽣的认证码(4位数字)

//String rand = request.getParameter("rand");

//rand = rand.substring(0,rand.indexOf("."));

String sRand = "";

// 如果要使⽤中⽂，必须定义字库，可以使⽤数组进⾏定义

// 这⾥直接写中⽂会出乱码，必须将中⽂转换为unicode编码

String[] str = { "A", "B", "C", "D", "E", "F", "G", "H", "J", "K",

"L", "M", "N", "P", "Q", "R", "S", "T", "U", "V", "W", "X",

"Y", "Z", "a", "b", "c", "d", "e", "f", "g", "h", "i", "j",

"k", "m", "n", "p", "s", "t", "u", "v", "w", "x", "y", "z",

"1", "2", "3", "4", "5", "6", "7", "8", "9" };

for (int i = 0; i < 5; i++) {

String rand = str[random.nextInt(str.length)];

sRand += rand;

// 将认证码显⽰到图象中

g.setColor(new Color(20 + random.nextInt(110), 20 + random

.nextInt(110), 20 + random.nextInt(110)));//调⽤函数出来的颜⾊相同，可能是因为种⼦太接近，所以只能直接⽣成

g.drawString(rand, 16 * i + 6, 19);

}

// 将认证码存⼊SESSION

session.setAttribute("rand", sRand);

// 图象⽣效

g.dispose(); // 输出图象到页⾯

ImageIO.write(image, "JPEG", response.getOutputStream());

out.clear();

out = pageContext.pushBody();

%>

login.jsp源码（使⽤验证码的页⾯）：

//使⽤验证码的页⾯login.jsp

<%@ page contentType="text/html" pageEncoding="GBK"%>

登陆页⾯

<%

// 乱码解决

request.setCharacterEncoding("GBK");

%>

登陆程序

<%=request.getAttribute("info") != null ? request

.getAttribute("info") : ""%>

⽤户ID：

密 码：

验证码：

效果如下：

2，使⽤Servlet⽣成验证码

IdentityServlet.java源码：

//IdentityServlet.java代码如下：

package com.helloweenvsfei.servlet;

import java.awt.Color;

import java.awt.Font;

import java.awt.Graphics2D;

import java.awt.image.BufferedImage;

import java.io.IOException;

import java.util.Random;

import javax.servlet.ServletException;

import javax.servlet.ServletOutputStream;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import com.sun.image.codec.jpeg.JPEGCodec;

import com.sun.image.codec.jpeg.JPEGImageEncoder;

public class IdentityServlet extends HttpServlet {

/**

*

*/

private static final long serialVersionUID = -479885884254942306L;

public static final char[] CHARS = { '2', '3', '4', '5', '6', '7', '8',

'9', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J', 'K', 'L', 'M',

'N', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z' };

public static Random random = new Random();