java生成验证码工具类

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生成后返回验证码字符

import java.awt.Color;import java.awt.Font;import java.awt.Graphics;import java.awt.Graphics2D;import java.awt.image.BufferedImage;import java.io.IOException;import java.util.Random;import javax.imageio.ImageIO;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;/** * 生成验证码工具类 * @author nikolas511 * */public class VerificationUtils{private static int WIDTH=100;//图片宽private static int HEIGHT=40;//图片长public static String getVerification(HttpServletRequest request, HttpServletResponse response) throws IOException{//构造一幅图片,并得到图行BufferedImage image = new BufferedImage(WIDTH, HEIGHT,BufferedImage.TYPE_INT_RGB); Graphics g = image.getGraphics();//设置图片的背景,并设置图片的边框setBackGround(g);//增加线条干扰setLine(g);//画出图片中的文字String text = setText((Graphics2D)g);//控制浏览器不要缓存,实际测试中浏览器不缓存response.addDateHeader("expries", -1);response.setHeader("Cache-Control", "no-cache");response.setHeader("Pragma","no-cache");//将图片用输出流输出到浏览器中ImageIO.write(image, "jpg", response.getOutputStream());return text;}private static String setText(Graphics2D g) {int x=6,y=32;String s ="0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";Color[] color ={Color.BLACK,Color.RED,Color.DARK_GRAY,Color.MAGENTA,Color.ORANGE,Color.YELLOW,Color.CYAN,Color.BLUE,Color.ORANGE,Color.GREEN,Color.PINK,Color.GRAY};String text = "";for(int i=0;i<4;i++){int num = new Random().nextInt(color.length);String ch =s.charAt(new Random().nextInt(s.length()))+"";text =text+ch;double degree = (new Random().nextInt(30))*Math.PI/180;if(!new Random().nextBoolean())degree=-degree;Color c = color[num];g.setColor(c);g.setFont(new Font(ch,Font.BOLD,30));g.rotate(degree,x,y);g.drawString(ch,x,y);g.rotate(-degree,x,y);x+=25;//此处设置字符间距}return text;}private static void setLine(Graphics g) {Color[] color ={Color.YELLOW,Color.CYAN,Color.BLUE,Color.ORANGE,Color.GREEN,Color.PINK};for(int i=0; i<=10; i++){int num = new Random().nextInt(color.length);Color c = color[num];g.setColor(c);int x1 = new Random().nextInt(150);int y1 = new Random().nextInt(40);int x2 = new Random().nextInt(150);int y2 = new Random().nextInt(40);g.drawLine(x1, y1, x2, y2);}}private static void setBackGround(Graphics g) {g.setColor(Color.LIGHT_GRAY);g.fillRect(0,0, WIDTH, HEIGHT);g.setColor(Color.BLACK);g.drawRect(1, 1, WIDTH-2, HEIGHT-2);}}

此处测试以servlet实例

import java.io.IOException;import java.io.PrintWriter;import javax.servlet.ServletException;import javax.servlet.annotation.WebServlet;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import cn.pjj.utils.VerificationUtils;@WebServlet("/VerificationServlet")public class VerificationServlet extends HttpServlet {private static final long serialVersionUID = 1L;protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {String text = VerificationUtils.getVerification(request, response);request.getSession().setAttribute("text", text);System.out.println(text);}protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {request.setCharacterEncoding("utf-8");response.setContentType("text/html;charset=utf-8");PrintWriter pw = response.getWriter();String checknum = request.getParameter("checknum");String text = (String) request.getSession().getAttribute("text");if(text.equalsIgnoreCase(checknum)){pw.write("images/MsgSent.gif");}else{pw.write("images/MsgError.gif");}pw.flush();pw.close();}}

下面为jsp页面,当输入4个字符后发送ajax请求,此处需要导入jquery的js文件

图片例子

<%@ page language="java" contentType="text/html; charset=UTF-8"    pageEncoding="UTF-8"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>Insert title here</title><script type="text/javascript" src="js/jquery-1.8.2.min.js"></script></head><body><table><tr><td>输入验证码:<input id="checknum" size="3" type="text" height="40" maxlength="4"name="checknum" onkeyup="check()" /></td><td><span id="res"></span> </td><td><img id="image"  onclick="changeImage(this)"src="${pageContext.request.contextPath}/VerificationServlet"></td></tr></table><script type="text/javascript">function changeImage(img) {img.src = img.src + "?" + new Date().getTime();$("#res").html("");$("#checknum").val("");}//去掉两边的空格function trim(str){str = str.replace(/^\s*/,"");str = str.replace(/\s*$/,"");return str;}</script><script type="text/javascript">function check(){var $checknum = $("#checknum");var $str = trim($checknum.val());if($str.length==4){$.ajax({type:"POST",url:"VerificationServlet?time=" + new Date().getTime(),data:{"checknum":$str},success:function(backData){var $res = $("#res").html("");$("<img src='"+backData+"' style='width:14px;height:14px' />").appendTo($res);}});}else{$("#res").html("");}}</script></body></html>

以上源码及其资料图片下载链接：http://pan.baidu.com/s/1bURheu 密码：5evt

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