java制作简单验证码功能

2019-11-26 10:59:28

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本文实例为大家分享了java制作简单验证码的具体代码，供大家参考，具体内容如下

在这里我们需要用到java的画笔工具，所以我们需要导入以下包
import="java.util.*,java.awt.*,java.awt.image.*,javax.imageio.*"

然后我就使用java脚本来实现一个小小的验证码

<%@ page contentType="image/jpeg; charset=utf-8"   language="java" import="java.util.*,java.awt.*,java.awt.image.*,javax.imageio.*"   pageEncoding="UTF-8"%>   <!-- 以上导入awt和awt.image包 --> <% 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%>" rel="external nofollow" >    <title>验证码</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">   </head>   <body>   <%!    //获取随机颜色    public Color getColor(){     Random random = new Random();     //使用rgb()随机产生颜色     int r = random.nextInt(256);     int g = random.nextInt(256);     int b = random.nextInt(256);          return new Color(r,g,b);    }        //获取随机数字 产生一个4位数    public String getNum(){     String str = "";     Random random = new Random();     for(int i = 0;i < 4;i++){      str += random.nextInt(10); //0-9     }     return str;    }    %>       <%    /* 清除缓存 */    response.setHeader("pragma", "mo-cache");    response.setHeader("cache-control", "no-cache");    response.setDateHeader("expires", 0);    //产生矩形框    BufferedImage image = new BufferedImage(80,30,BufferedImage.TYPE_INT_RGB);    //获取画笔工具    Graphics g = image.getGraphics();    //设置矩形框的颜色    g.setColor(new Color(200,200,200));    //设置坐标和宽高    g.fillRect(0, 0, 80, 30);        //随机产生干扰线    for(int i = 0;i < 30;i++){     Random random = new Random();     int x = random.nextInt(80);     int y = random.nextInt(30);     int x1 = random.nextInt(x + 10);     int y1 = random.nextInt(y + 10);     //设置随机颜色     g.setColor(getColor());     //画出来     g.drawLine(x, y, x1, y1);    }        //字的颜色和数字    g.setFont(new Font("Microsoft YaHei",Font.BOLD,16));    g.setColor(Color.BLACK);    //获取随机数字    String checkNum = getNum();        //给字拼接空格    StringBuffer sb = new StringBuffer();    for(int i = 0;i < checkNum.length();i++){     sb.append(checkNum.charAt(i) + " ");    }    //画出数字    g.drawString(sb.toString(), 15, 20);    //存入session域中    session.setAttribute("CHECKNUM", checkNum); //例如1010    //将图像以jpeg的形式通过字节流输出    ImageIO.write(image, "jpeg", response.getOutputStream());    //清除缓存    out.clear();    //放入body中    out = pageContext.pushBody();    %>     </body> </html>

结果如下：