图片验证码

选择字号： 超大 标准 发布时间：2013-3-29 14:51:30 | 作者：admin | 0个评论 | 人浏览

 package net.lisoft.service.servlet;

 

import java.awt.Color;

import java.awt.Font;

import java.awt.Graphics2D;

import java.awt.image.BufferedImage;

import java.io.IOException;//这行好像不要也行？

import java.util.Random;

import javax.imageio.ImageIO;

import javax.servlet.ServletException;

import javax.servlet.ServletOutputStream;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.http.HttpSession;

 

public class CInentityServlet extends HttpServlet {

// 高度

private int width = 90;

// 宽度

private int height = 20;

 

protected void service(HttpServletRequest req, HttpServletResponse resp)

throws ServletException, java.io.IOException {

BufferedImage buffImg = new BufferedImage(width, height,

BufferedImage.TYPE_INT_RGB);

Graphics2D g = buffImg.createGraphics();

Random random = new Random();

g.setColor(Color.WHITE);

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

// 设置字体

Font font = new Font("Times New Roman", Font.BOLD, 20);

g.setFont(font);

// 画边框

g.setColor(Color.GRAY);

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

g.setColor(Color.GRAY);

// 随机产生干扰线

for (int i = 0; i < 50; i++) {

int x = random.nextInt(width);

int y = random.nextInt(height);

int x1 = random.nextInt(2);

int y1 = random.nextInt(2);

g.drawLine(x, y, x + x1, y + y1);

}

// 数字字母集合(为方便辨认只有小写字母)

char[] numbersAndLettersStore = ("ABCDEFGHIJKLMNOPQRSTUVWXYZ")

.toCharArray();

String randomCode = "";// 这个地方不能为null,如果为null那么session中也会出现null，不知道什么原因

int red = 0, green = 0, blue = 0;

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

red = random.nextInt(255);

green = random.nextInt(255);

blue = random.nextInt(255);

g.setColor(new Color(red, green, blue));

String tem = String.valueOf(numbersAndLettersStore[random

.nextInt(numbersAndLettersStore.length)]);

randomCode += tem;

g.drawString(tem, 15 * i + 16, 17);

}

// 验证码保存到Session范围

HttpSession session = req.getSession();

session.setAttribute("logincode", randomCode.toString());

// 禁止缓存

resp.setHeader("Prama", "no-cache");

resp.setHeader("Coche-Control", "no-cache");

resp.setDateHeader("Expires", 0);

resp.setContentType("image/jpeg");

// 将图像输出到

ServletOutputStream sos = resp.getOutputStream();

ImageIO.write(buffImg, "jpeg", sos);

sos.close();

}

}

 

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