Java生成图片验证码
import java.io.*;import java.net.*;import javax.servlet.*;import javax.servlet.http.*;import java.awt.*;import java.awt.image.*;import java.util.*;import javax.imageio.*;/** * * @author http://www.tot.name * @version */public class Image extends HttpServlet {
/** Processes requests for both HTTP <code>GET</code> and <code>POST</code> methods. * @param request servlet request * @param response servlet response */ protected void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("image/jpeg"); response.setHeader("Pragma","No-cache"); response.setHeader("Cache-Control","no-cache"); response.setDateHeader("Expires", 0); HttpSession session=request.getSession(); // 在内存中创建图象 int width=60, height=20; BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
// 获取图形上下文 Graphics g = image.getGraphics();
//生成随机类 Random random = new Random();
// 设定背景色 g.setColor(getRandColor(200,250)); g.fillRect(0, 0, width, height);
//设定字体 g.setFont(new Font("Times New Roman",Font.PLAIN,18));
//画边框 //g.setColor(new Color()); //g.drawRect(0,0,width-1,height-1);
// 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 g.setColor(getRandColor(160,200)); for (int i=0;i<155;i++) { int x = random.nextInt(width); int y = random.nextInt(height); int xl = random.nextInt(12); int yl = random.nextInt(12); g.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 g.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 g.drawString(rand,13*i+6,16); }
// 将认证码存入SESSION session.setAttribute("rand",sRand); // 图象生效 g.dispose(); ServletOutputStream responseOutputStream =response.getOutputStream(); // 输出图象到页面 ImageIO.write(image, "JPEG", responseOutputStream);
//以下关闭输入流！ responseOutputStream.flush(); responseOutputStream.close(); } 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); } // <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code."> /** Handles the HTTP <code>GET</code> method. * @param request servlet request * @param response servlet response */ protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { processRequest(request, response); }
/** Handles the HTTP <code>POST</code> method. * @param request servlet request * @param response servlet response */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { processRequest(request, response); }
/** Returns a short description of the servlet. */ public String getServletInfo() { return "Short description"; } // </editor-fold>}
---------------使用验证码图片的文件---------index.jsp------------------------------------
<%@ page contentType="text/html;charset=gb2312" %><!DOCTYPE HTML PUBLIC "-//W 3C //DTD HTML 4.01 Transitional//EN"><html><head><title>认证码输入页面</title><meta http-equiv="Content-Type" content="text/html; charset=gb2312"><META HTTP-EQUIV="Pragma" CONTENT="no-cache"> <META HTTP-EQUIV="Cache-Control" CONTENT="no-cache"> <META HTTP-EQUIV="Expires" CONTENT="0"> </head><body><form method=post action="check.jsp"><table><tr><td align=left>系统产生的认证码：</td><td><img border=0 src="http://www.zhmy.com/image"></td></tr><tr><td align=left>输入上面的认证码：</td><td><input type=text name=rand maxlength=4 value=""></td></tr><tr><td colspan=2 align=center><input type=submit value="提交检测"></td></tr></form></body></html>
-----------------验证的页面----------check.jsp------------------------------
<%@ page contentType="text/html; charset=gb2312" language="java" import="java.sql.*" errorPage="" %><html><head><title>认证码验证页面</title><meta http-equiv="Content-Type" content="text/html; charset=gb2312"><META HTTP-EQUIV="Pragma" CONTENT="no-cache"> <META HTTP-EQUIV="Cache-Control" CONTENT="no-cache"> <META HTTP-EQUIV="Expires" CONTENT="0"> </head>
<body><% String rand = (String)session.getAttribute("rand");String input = request.getParameter("rand");%>系统产生的认证码为： <%= rand %><br/>您输入的认证码为： <%= input %><br/><br/><% if (rand.equals(input)) {%><font color=green>输入相同，认证成功！</font><% } else {%><font color=red>输入不同，认证失败！</font><% }%></body></html>
