寒假快结束了吧
假期撸多了吧
红包还有吧
-好了吧
入正题
前几天，进了一个清远的政府网站，我无法接受的不是页面好不好看，而是验证码一直卡住
还是 用JSP的-嗯慢慢的想了下我会不会写呢.....嗯我水平真菜
好了上代码
1.先把生成验证码的图片封装为一个JavaBean,这个JavaBean的源代码：
package com.bean;
import java.awt.Color;
import java.awt.Font;
import java.awt.GradientPaint;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Random;
import javax.imageio.ImageIO;
/**
* @author Administrator
* 生成验证码
*/
public class MakeCertPic {
//根据以下字母数字生成,已经把一些容易混淆的删除如：i,l,1,0,o
private char mapTable[]={
'a','b','c','d','e','f',
'g','h','j','k',
'm','n','q','p','r',
's','t','u','v','w','x',
'y','z','2','3','4','5',
'6','7','8','9'};
/*
* 功能：生成彩色验证图片
* 参数width为生成图片的宽度,height为图片高度,os为页面输出流
*/
public String getCertpic(int width,int height,OutputStream os){
if(width<=0){
width=60;
}
if(height<=0){
height=20;
}
BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_BGR);
//获取图像上下文
Graphics g =image.getGraphics();
//设置背景颜色
g.setColor(new Color(0xDCDCDC));
g.fillRect(0, 0, width, height);
//边框
g.setColor(Color.black);
g.drawRect(0, 0, width-1, height-1);
//取随机验证码
String strEnsure = "";
//4代表4为验证码，如需要可做修改
for(int i =0;i<4;++i){
strEnsure +=mapTable[(int)(mapTable.length*Math.random())];
}
g.setColor(Color.black);
g.setFont(new Font("Atlantic Inline",Font.PLAIN,18));
String str =strEnsure.substring(0,1);
g.drawString(str,8,17);
str = strEnsure.substring(1, 2);
g.drawString(str,20,15);
str = strEnsure.substring(2, 3);
g.drawString(str,35,18);
str = strEnsure.substring(3, 4);
g.drawString(str,45,15);
//产生10个干扰点
Random rand = new Random();
for(int i=0;i<10;i++){
int x =rand.nextInt(width);
int y =rand.nextInt(height);
g.drawOval(x, y, 1, 1);
}
//释放图形上下文
g.dispose();
try{
ImageIO.write(image, "JPEG", os);
}catch (IOException e) {
// TODO: handle exception
return "";
}
return strEnsure;
}
}
为了造成一些干扰，我随机花了10个干扰点，如果想多点，可以在for循环那个自己加大。
2.在编写一个servlet输出生成的验证码，代码如下:
package com.bean;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class ShowCertPic extends HttpServlet {
public void service(HttpServletRequest request,HttpServletResponse response)throws ServletException,IOException{
MakeCertPic image =new MakeCertPic();
String str = image.getCertpic(0, 0, response.getOutputStream());
request.getSession().setAttribute("certCode2", str);
}
/**
* Destruction of the servlet. <br>
*/
public void destroy() {
super.destroy(); // Just puts "destroy" string in log
// Put your code here
}
/**
* Initialization of the servlet. <br>
*
* @throws ServletException if an error occurs
*/
public void init() throws ServletException {
// Put your code here
}
}
3.在web.xml部署应该会了吧，但是我为了方便是直接把url-pattern为/ShowCertPic
最后就是登录的JSP代码，这个你们随便测试就好了
<%@ page language="java" import="java.util.*" contentType="text/html; charset=utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>登录页面</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
<script type="text/JavaScript" language="javascript">
function change(){
var o = document.getElementById("random");
var timenow = new Date().getTime();
o.src = "<%=path%>/ShowCertPic?d=" + timenow;
}
</script>
</head>
<body>
<form action="index.jsp" method="post">
<h1>系统登录测试</h1>
<p>
用户名：
<input type="text" name="username" />
</p>
<p>
密码：
<input type="password" name="password" />
</p>
<p>
验证码：
<input type="password" name="certCode" />
<img alt="code" id="random" src="ShowCertPic">
<input type="button" value="换一张图片" id="label" onclick="change()"></input>
</p>
<input type="submit" value="登录">
</form>
</body>
</html>
随机生成的代码为：
<img alt="code" src="ShowCertPic">
点击更新验证码代码为：
<script type="text/JavaScript" language="javascript">
function change(){
var o = document.getElementById("random");
var timenow = new Date().getTime();
o.src = "<%=path%>/ShowCertPic?d=" + timenow;
}
</script>
运行结果图：
我知道你会说，随便打上去也可以吧
那么你可以去做一个验证是否正确，代码我自己瞧这个的
? <%
String certCode = request.getParameter("certCode");
String certCode2 = (String)session.getAttribute("certCode2");
if(certCode != null && certCode2 != null){
if(certCode.equals(certCode2)){
out.println("验证码输入正确！");
}else{
out.println("验证码输入不正确，请重新输入！");
}
}
%>