最近,在弄一个微薄类的sns项目,需要用到验证码,记录下。代码如下,主要是在serlet中实现图片生成,跟随机数,然后把随机数同步到session中
package com.ecar.portal.common.servlet; import java.io.*; import java.util.*; import com.sun.image.codec.jpeg.*; import javax.servlet.*; import javax.servlet.http.*; import java.awt.*; import java.awt.image.*; /** * 功能:调用AuthServlet可以生成一个验证码图片,图片的宽度和高度可以自定义 * 调用格式: /servlet/AuthServlet?width=60&height=20 * 或者/servlet/AuthServlet * 时间:2010-8-6 * * @author: lyj */ public class VerifyServlet extends HttpServlet { private Font mFont=new Font("Times New Roman", Font.BOLD,22);//设置字体 //static String AuthCode=""; // 处理post public void doPost(HttpServletRequest request,HttpServletResponse response) throws ServletException,IOException { doGet(request,response); } public void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException,IOException { // 取得一个1000-9999的随机数 //System.out.println("servlert方法调用"); HttpSession session=request.getSession();//request.getSession(false)当参数为false时,有可能不创建session //session.setAttribute("getImg",s); response.setContentType("image/gif"); response.setHeader("Pragma","No-cache"); response.setHeader("Cache-Control","no-cache"); response.setDateHeader("Expires", 0); int width=60; int height=20; if(request.getParameter("width")!=null && !request.getParameter("width").equals("")) width = Integer.parseInt(request.getParameter("width")); if(request.getParameter("height")!=null && !request.getParameter("height").equals("")) height = Integer.parseInt(request.getParameter("height")); ServletOutputStream out=response.getOutputStream(); BufferedImage image=new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB); //设置图片大小的 Graphics gra=image.getGraphics(); Random random=new Random(); gra.setColor(getRandColor(233,244)); //设置背景色 gra.fillRect(0,0,width,height); gra.setColor(Color.black); //设置字体色 gra.setFont(mFont); // 随机产生155条干扰线,使图象中的认证码不易被其它程序探测到 gra.setColor(getRandColor(160,200)); for (int i=0;i<150;i++) { int x = random.nextInt(width); int y = random.nextInt(height); int xl = random.nextInt(12); int yl = random.nextInt(12); gra.drawLine(x,y,x+xl,y+yl); } // 取随机产生的认证码(4位数字) String sRand=""; for (int i=0;i<4;i++){ String rand=String.valueOf(random.nextInt(10)); sRand+=rand; // 将认证码显示到图象中 gra.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));//调用函数出来的颜色相同,可能是因为种子太接近,所以只能直接生成 gra.drawString(rand,13*i+6,18); } //ystem.out.println("showimage="+sRand); //session.setAttribute("getImg",sRand); session.setAttribute("AuthCode",sRand); //AuthCode = sRand; //session.putValue("AuthCode",sRand); JPEGImageEncoder encoder=JPEGCodec.createJPEGEncoder(out); encoder.encode(image); //out.flush(); } static Color getRandColor(int fc,int bc){//给定范围获得随机颜色 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); } static public String getAuthCode(HttpSession session){//返回验证 return (String)session.getAttribute("AuthCode"); } }