java 验证码

 

验证码： jsp 

 

1. 数字型：

 

<%@ page language="java" contentType="image/png"
	import="java.util.*,java.awt.*,java.awt.image.*" pageEncoding="GBK"%>
<%
	out.clear();	
//在内存中创建图象  
int width = 85, 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));  

// 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(6位数字)  
String sRand = "";  
for (int i = 0; i < 6; 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);
//ActionContext.getContext().getSession().put("rand", sRand);  

// 图象生效  
g.dispose();  
out.clearBuffer();// 清空缓冲区
javax.imageio.ImageIO.write(image, "png", response.getOutputStream());// 把内存的图片编码到输出流, 参数依次为: 图片对象, 格式(png,jpg), 输出流
response.flushBuffer();
out.clear();
out = pageContext.pushBody();
%>
<%!
/* 
 * 给定范围获得随机颜色 
 */  
private Color getRandColor(int fc, int bc) {  
    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);  
}  
%>

 

2. 字母型

<%@ page language="java" contentType="image/png"
	import="java.util.*,java.awt.*,java.awt.image.*" pageEncoding="GBK"%>
<%!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);
	}%>


<%
//将过期日期设置为一个过去时间

response.setHeader("Expires", "Sat, 6 May 1995 12:00:00 GMT");

// 设置 HTTP/1.1 no-cache 头
response.setHeader("Cache-Control", "no-store,no-cache,must-revalidate");

// 设置 IE 扩展 HTTP/1.1 no-cache headers， 用户自己添加
response.addHeader("Cache-Control", "post-check=0, pre-check=0");

// 设置标准 HTTP/1.0 no-cache header.
response.setHeader("Pragma", "no-cache");

	out.clear();	
	//response.reset();// 清空以前缓冲区
	//生成随机类
	Random random = new Random();
	BufferedImage img = new BufferedImage(60, 20,
			BufferedImage.TYPE_INT_RGB);// 创建彩色缓冲图, 宽 60, 高 20

	Graphics g = img.getGraphics();// 画笔对象

	// 填充白色的背景
	g.setColor(Color.white);
	g.fillRect(0, 0, 100, 20);

	//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(100);
		int y = random.nextInt(20);
		int xl = random.nextInt(12);
		int yl = random.nextInt(12);
		g.drawLine(x, y, x + xl, y + yl);
	}

	// 绘制蓝色文字
	g.setColor(Color.blue);

	// 生成 4 位随机数字验证码并存入session, 然后输出到图片中
	
	String code = "";
	
	for(int i = 0; i < 4; i++) {
		Random rand = new Random();
		//code += rand.nextInt(10) + ""; // 随机数字
		code += (char) ( rand.nextInt(26) + 'A') ; // 随机字母
	}

	session.setAttribute("regcode", code);// 存放值名字为 regcode

	//设定字体
	g.setFont(new Font("Times New Roman", Font.PLAIN, 20));

	g.drawString(code, 2, 16);

	g.dispose();// 关闭对象, 释放内存, 刷新到图形对象

	out.clearBuffer();// 清空缓冲区
	javax.imageio.ImageIO.write(img, "png", response.getOutputStream());// 把内存的图片编码到输出流, 参数依次为: 图片对象, 格式(png,jpg), 输出流
	out.flush(); // 输出全部内容, 防止 Tomcat 后台报 Socket 错误, IE 6 下会出现问题
	//out.close();// 关闭, 防止后台无法写入数据
%>

 

 

3. 调用 该jsp 输出验证码

 

<%@ page language="java" import="java.util.*" 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>My JSP 'index.jsp' starting page</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">
	<!--
	<link rel="stylesheet" type="text/css" href="styles.css">
	-->
	<script type="text/javascript">
	//载入新的验证码
	function loadNewCode() {
		document.getElementById('regcodeImg').src = '${basePath }test.jsp?d=' + new Date().getTime();
	}
	</script>
  </head>
  
  <body>
   <img src="${basePath }test.jsp?TTT=<%=Math.random()*100 %>" width="58" height="20"  style="CURSOR: pointer" id=regcodeImg title=看不清楚?点击换一张 onclick=loadNewCode();  >
  </body>
</html>