工具类_验证码

gaozhonghui

<%@page import="java.io.OutputStream"%><%@ page contentType="image/jpeg" pageEncoding="GBK" import="java.awt.*,java.awt.image.*,java.util.*,javax.imageio.*" %><%!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);}%><%//设置页面不缓存response.setHeader("Pragma","No-cache");response.setHeader("Cache-Control","no-cache");response.setDateHeader("Expires", 0);// 在内存中创建图象int width=56, 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("Courier New", Font.PLAIN, 18));//画边框//g.setColor(new Color(55,55,55));//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(10),20+random.nextInt(110),20+random.nextInt(210)));//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+3, 16);}String sessionName = request.getParameter("VIName");// 将认证码存入SESSIONif(sessionName==null) sessionName = "";session.setAttribute("will_session_randCode_"+sessionName, sRand);// 图象生效g.dispose();// 输出图象到页面OutputStream os = response.getOutputStream();ImageIO.write(image, "JPEG", os);os.flush();os.close();response.flushBuffer();out.clear();out = pageContext.pushBody();%>