Servlet中产生验证码并在添加至jsp中

来源：互联网发布：企业数据集成编辑：程序博客网时间：2024/05/29 16:46

以下是Servlet产生验证码：

package com.web;

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.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
*
*@package:com.verifacationCode
*@name:VerificationCodeServlet.java
*@Dscription:处理验证码
*@author: hngd-DQ-zy
*@Date:2014-8-14 下午2:40:51
*/
public class VerificationCode extends HttpServlet {

private static final long serialVersionUID = 1L;
private final int WIDTH=150;
private final int HEIGHT=30;

public void doGet(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException {
  //准备画布
  BufferedImage image=new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);
  //准备画笔
  Graphics g=image.getGraphics();
  //设置背景颜色
  setBackground(g);
  //设置边框
  setBorder(g);
  //画干扰线
  drawRandomLine(g);
  //画文字
  drawRandomNum((Graphics2D)g);

  //设置浏览器不要缓存

  response.setContentType("image/jpeg");
  response.setDateHeader("expries",-1);
  response.setHeader("Cache-Control","no-cache");
  response.setHeader("Pragma","no-cache");
  ImageIO.write(image, "jpg", response.getOutputStream());

}

private void setBackground(Graphics g){
  g.setColor(Color.WHITE);
  g.fillRect(0, 0, WIDTH, HEIGHT);

}

private void setBorder(Graphics g){
  g.setColor(Color.BLUE);
  g.drawRect(1, 1, WIDTH-2, HEIGHT-2);

}

private void drawRandomLine(Graphics g){
  g.setColor(Color.GREEN);
  for(int i=0;i<8;i++){
   int x1=new Random().nextInt(WIDTH);
   int y1=new Random().nextInt(HEIGHT);
   int x2=new Random().nextInt(WIDTH);
   int y2=new Random().nextInt(HEIGHT);
   g.drawLine(x1, y1, x2, y2);
  }

}

private void drawRandomNum(Graphics2D g){
  //StringBuffer s=new StringBuffer();
  g.setColor(Color.RED);
  g.setFont(new Font("宋体",Font.BOLD,20));
  String base="1234567890ABCDEFGHJKLMNOPQRSTUVWXYZ";
  int x=20;
  for(int i=0;i<4;i++){
   //随机产生旋转角度（以度为单位且小于40度）
   int degree=new Random().nextInt()%40;
   //在提前准备好的字符串中随机选择一个字符
   String ch=base.charAt(new Random().nextInt(base.length()-1))+"";
   //设置选择弧度和基点
   g.rotate(degree*(Math.PI/180), x, 20);
   g.drawString(ch, x, 25);
   //第一个字旋转完毕后第二个字要还原
   g.rotate(-degree * Math.PI / 180, x, 20);
   x+=30;
  }

}

以下是jsp中嵌入验证码：

<%@ page language="java" import="java.util.*" pageEncoding="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>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">

<script type="text/javascript">
  function newimg(img){
   img.src=img.src+"?"+new Date().getTime();
  }

</script>

<style type="text/css">
  #id-1{
   cursor: pointer;
  }
</style>

</head>

<body>
   <form>
   <img id="img-1" src="VerificationCode" onclick="newimg(this)" />
   <input id="id-1" type="button" value="刷新" />
   </form>
</body>
</html>

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