java验证码/servlet

 

项目结构如图一：

 第一步，新建PictureCode.java：

 

 

package com.servlet;import java.awt.BasicStroke;import java.awt.Color;import java.awt.Font;import java.awt.Graphics;import java.awt.Graphics2D;import java.awt.geom.AffineTransform;import java.awt.geom.Line2D;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 PictureCode extends HttpServlet{    @Override    protected void service(HttpServletRequest req, HttpServletResponse resp)            throws ServletException, IOException    {        //设置不缓存        resp.setHeader("pragma", "no-cache");        resp.setHeader("cache-control", "no-cache");        resp.setDateHeader("expires", 0);        //指定生成的图片的格式        resp.setContentType("image/jpeg");        //验证码的张宽        int width=80,height=30;        //图片流        BufferedImage image=new BufferedImage(width, height, BufferedImage.TYPE_INT_BGR);        Graphics g=image.getGraphics();     //创建Graphics对象,其作用相当于画笔         Graphics2D g2d=(Graphics2D)g;       //创建Grapchics2D对象         Font mfont=new Font("楷体",Font.BOLD,16); //定义字体样式         g.setColor(getRandColor(200,250));         g.fillRect(0, 0, width, height);    //绘制背景         g.setFont(mfont);                   //设置字体         g.setColor(getRandColor(180,200));       //绘制100条颜色和位置全部为随机产生的线条,该线条为2f         Random random=new Random();        for (int i = 0; i < 100; i++)        {            int x=random.nextInt(width-1);            int y=random.nextInt(height-1);            int x1=random.nextInt(6)+1;            int y1=random.nextInt(12)+1;            BasicStroke bs=new BasicStroke(2f, BasicStroke.CAP_BUTT, BasicStroke.JOIN_BEVEL);            Line2D line2d=new Line2D.Double(x,y,x+x1,y+y1);            g2d.setStroke(bs);            g2d.draw(line2d);        }        //输出由英文，数字，和中文随机组成的验证文字，具体的组合方式根据生成随机数确定。         String sRand="";         String ctmp="";         int itmp=0;         //制定输出的验证码为四位         for(int i=0;i<4;i++){             //random.nextInt(2)在0-2中间去随机，不包含2，这样是为了下面不去生成中文验证码，验证出现中文时，不好判断            switch(random.nextInt(2)){                 case 1:     //生成A-Z的字母                      itmp=random.nextInt(26)+65;                      ctmp=String.valueOf((char)itmp);                      break;                 default:                      itmp=random.nextInt(10)+48;                      ctmp=String.valueOf((char)itmp);                      break;             }             sRand+=ctmp;            Color color=new Color(20+random.nextInt(110),20+random.nextInt(110),random.nextInt(110));             g.setColor(color);             //将生成的随机数进行随机缩放并旋转制定角度 PS.建议不要对文字进行缩放与旋转,因为这样图片可能不正常显示             /*将文字旋转制定角度*/             Graphics2D g2d_word=(Graphics2D)g;             AffineTransform trans=new AffineTransform();             trans.rotate((45)*3.14/180,15*i+8,7);             /*缩放文字*/             float scaleSize=random.nextFloat()+0.8f;             if(scaleSize>1f) scaleSize=1f;             trans.scale(scaleSize, scaleSize);             g2d_word.setTransform(trans);             g.drawString(ctmp, 15*i+18, 14);         }         //打开session，并放入验证图片        HttpSession session=req.getSession(true);        session.setAttribute("randCheckCode", sRand);         g.dispose();    //释放g所占用的系统资源         ImageIO.write(image,"JPEG",resp.getOutputStream()); //输出图片     }    public PictureCode()    {        super();    }    public void destroy()    {        super.destroy(); // Just puts "destroy" string in log        // Put your code here    }    public void init() throws ServletException    {        super.init();    }    /*该方法主要作用是获得随机生成的颜色*/      public Color getRandColor(int s,int e){         Random random=new Random ();         if(s>255) s=255;         if(e>255) e=255;         int r,g,b;         r=s+random.nextInt(e-s);    //随机生成RGB颜色中的r值         g=s+random.nextInt(e-s);    //随机生成RGB颜色中的g值         b=s+random.nextInt(e-s);    //随机生成RGB颜色中的b值         return new Color(r,g,b);     } }

 

 

 

第二步，新建index.jsp和Check.jsp

 

index.jsp:

 

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html>  <head>    <title>My JSP 'index.jsp' starting page</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">function myReload() {     document.getElementById("PictureCode").src = document             .getElementById("PictureCode").src             + "?nocache=" + new Date().getTime(); } </script>  </head>  <body>    <form action="Check.jsp" method="post">            <input name="checkCode" type="text" id="checkCode"                  size="8" ,maxlength="4" />             <img src="PictureCode" id="PictureCode" align="middle">             <a href="" onclick="myReload()">&nbsp;看不清,换一个</a>             <input type="submit" value="提交" />     </form>  </body></html>

 

 

Check.jsp:

 

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html>  <head>    <base href="<%=basePath%>">    <title>My JSP 'index.jsp' starting page</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">-->  </head>  <body>     <%         String checkcode=request.getParameter("checkCode");         if(checkcode.equals("")||checkcode==null){             out.print("<script>alert('请输入验证码');window.location.href('index.jsp')</script>");         }else{             if(!checkcode.equalsIgnoreCase((String)session.getAttribute("randCheckCode"))){                 out.print("<script>alert('验证码不正确,请重新输入');history.back(-1);</script>");             }else{                 out.print("登录成功;<script>window.location.href('http://www.google.com')</script>");             }         }      %>   </body></html>

 

 

 

第四步：配置web.xml中的servlet，部署运行：

web.xml:

<?xml version="1.0" encoding="UTF-8"?><web-app version="2.5"xmlns="http://java.sun.com/xml/ns/javaee"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://java.sun.com/xml/ns/javaeehttp://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">  <servlet>    <servlet-name>PictureCode</servlet-name>    <servlet-class>com.servlet.PictureCode</servlet-class>  </servlet>  <servlet-mapping>    <servlet-name>PictureCode</servlet-name>    <url-pattern>/PictureCode</url-pattern>  </servlet-mapping>  <welcome-file-list>    <welcome-file>index.jsp</welcome-file>  </welcome-file-list></web-app>

 

 

在tomcat等服务器中部署后，打开浏览器键入：

http://localhost:8080/checkcode2/

即可查看到如图二，图三中，随机生成的验证码