①servlet代码绘画验证码图片
package com.util.servlet;
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.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
public class AuthImageServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
//设置字母的大小,大小
private Font mFont = new Font("Times New Roman", Font.PLAIN, 22);
public void init() throws ServletException
{
super.init();
}
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);
}
public void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
response.setHeader("Pragma","No-cache");
response.setHeader("Cache-Control","no-cache");
response.setDateHeader("Expires", 0);
//表明生成的响应是图片
response.setContentType("image/jpeg");
int width=80, height=35;/*设置画布宽度和高度*/
BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
Graphics g = image.getGraphics();
Random random = new Random();
g.setColor(getRandColor(200,250));
g.fillRect(1, 1, width-1, height-1);
g.setColor(new Color(102,102,102));
g.drawRect(0, 0, width-1, height-1);
g.setFont(mFont);
g.setColor(getRandColor(160,200));
//画随机线
for (int i=0;i<155;i++)
{
int x = random.nextInt(width - 1);
int y = random.nextInt(height - 1);
int xl = random.nextInt(6) + 1;
int yl = random.nextInt(12) + 1;
g.drawLine(x,y,x + xl,y + yl);
}
//从另一方向画随机线
for (int i = 0;i < 70;i++)
{
int x = random.nextInt(width - 1);
int y = random.nextInt(height - 1);
int xl = random.nextInt(12) + 1;
int yl = random.nextInt(6) + 1;
g.drawLine(x,y,x - xl,y - yl);
}
//生成随机数,并将随机数字转换为字母
String sRand="";
char ctmp = 0 ;
for (int i=0;i<4;i++)
{
//ASCII码:65～90为26个大写英文字母,97～122号为26个小写英文字母,48～57为0到9十个阿拉伯数字
int itmp = 0;
int codeNum = random.nextInt(9);//产生随机数,决定产生数字还是字母
if(codeNum % 2 == 0){//绘画大写字母
codeNum = random.nextInt(9);//产生随机数,决定产生大写字母还是小写字母
if(codeNum % 2 == 0){//产生小写字母
itmp = random.nextInt(26) + 97;
ctmp = (char)itmp;
}else{//产生大写字母
itmp = random.nextInt(26) + 65;
ctmp = (char)itmp;
}
sRand += String.valueOf(ctmp);//将产生的字母字符拼接成字符串,存放到session中
}else{//产生数字
ctmp = (char)(random.nextInt(10)+48);
sRand += String.valueOf(ctmp);//将产生的数字拼接成字符串,存放到session中
}
g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));
int intY = random.nextInt(8);//产生随机数控制纵坐标
g.drawString(String.valueOf(ctmp),15*i+10,16+intY);//控制每个字符的绘画位置
}
HttpSession session = request.getSession(true);
session.setAttribute("rand",sRand);/*将验证码放入session中进行验证*/
g.dispose();
ImageIO.write(image, "JPEG", response.getOutputStream());
}
}
③web.xml的修改
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" version="2.5">
<servlet>
<servlet-name>AuthImageServlet</servlet-name>
<servlet-class>com.util.servlet.AuthImageServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>AuthImageServlet</servlet-name>
<url-pattern>/servlet/AuthImageServlet</url-pattern>
</servlet-mapping>
<servlet>
<servlet-name>CheckCodeIsRight</servlet-name>
<servlet-class>com.util.servlet.CheckCodeIsRightServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>CheckCodeIsRight</servlet-name>
<url-pattern>/servlet/CheckCodeIsRight</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>
④JSP页面的编写
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>验证码</title>
<script type="text/javascript" src="./comm/js/jquery.js"></script>
<script type="text/javascript">
$(function() {
$("#submit").click(function() {
var code = $("#code").val();
$.ajax({
url : "servlet/CheckCodeIsRight",
type : "POST",
data : {"code" : code},
dataType : "text",
async : false,//同步执行
erro : function(data){alert("erro");},
success : function(data) {
if(data == "1"){
alert("验证码输入正确");
}else{
alert("验证码输入有误!");
changeCode();s
}
}
});
});
})
function changeCode() {
var imgNode = document.getElementById("vimg");
imgNode.src = "servlet/AuthImageServlet?t=" + Math.random(); // 防止浏览器缓存的问题
}
</script>
</head>
<body>
<form action="checkServlet" method="post">
<label>输入验证码</label><br /> <input type="text" name="randomCode"
id="code" /> <img style="cursor: pointer;" id="vimg"
title="看不清?点击换一个" onclick="changeCode();"
src="servlet/AuthImageServlet"> <br /> <input type="button"
value="submit" id="submit">
</form>
</body>
</html>