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【javaweb】使用java制作简单的验证码

2017-11-07 22:20 411 查看

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"%>

<%
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>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:

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