java jsp实现登录验证码_JAVA_编程开发_程序员俱乐部

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java jsp实现登录验证码

 2013/10/9 19:01:45  为了明天而努力  程序员俱乐部  我要评论(0)
  • 摘要:javajsp实现登录验证码工作中使用的javajsp实现的登录验证码。代码记录如下:1.登录主页面(login.jsp)<%@pagelanguage="java"contentType="text/html;charset=UTF-8"pageEncoding="UTF-8"%><!DOCTYPEhtmlPUBLIC"-//W3C//DTDHTML4.01Transitional//EN""http://www.w3.org/TR/html4/loose.dtd">
  • 标签:实现 Java JS

java jsp实现登录验证码

工作中使用的java jsp实现的登录验证码。代码记录如下:

1.登录主页面(login.jsp)

class="java" name="code"><%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>登录</title>
<script type="text/javascript">
	function refresh() {
		//IE存在缓存,需要new Date()实现更换路径的作用
		document.getElementById("image").src="../login/image.jsp?"+new Date();
	}
</script>
</head>
<body>
	<form action="../login/check.jsp" method="post" id="loginForm" name="loginForm">
		用户名:<input type="text" name="userName">
		密码:<input type="password" name="userPwd">
		验证码:<input type="text" name="code" maxlength="4">
		<img id="image" border="0"  onclick="refresh()" src="../login/image.jsp" title="点击更换图片">
		<input type="submit" value="登录">
	</form>
</body>
</html>

?2. 验证码生成jsp(image.jsp)

<%@page import="javax.imageio.ImageIO"%>
<%@page import="java.awt.Font"%>
<%@page import="java.awt.Graphics"%>
<%@page import="java.awt.image.BufferedImage"%>
<%@page import="java.util.Random"%>
<%@page import="java.awt.Color"%>
<%@ page language="java" contentType="image/JPEG; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%!
	//获取随机颜色
	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);
	}
%>
<%
	//设置页面不缓存 
	response.setHeader("Pragma", "No-cache");
	response.setHeader("Cache-Control", "no-cache");   
    response.setDateHeader("Expires", 0);
    //在内存中创建图像
    int width = 60;
    int height = 20;
    BufferedImage image = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);
    //获取图形上下文
    Graphics g = image.getGraphics();
    //随机类
    Random random = new Random();
    //设定背景
    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));
   //随机产生干扰线
   g.setColor(getRandColor(160, 200));   
   for (int i = 0; i < 100; 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);   
   } 
   //随机产生4位验证码
   String[] codes = {"2","3","4","5","6","7","8","9","A","B","C","D","E","F","G","H","J","K","L","M","N","P","Q","R","S","T","U","V","W","X","Y","Z"};
   String code = "";
   for(int i=0;i<4;i++){
	   String str = codes[random.nextInt(codes.length)];
	   code += str;
	   // 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(str, 13 * i + 6, 16);   
   }
	// 将认证码存入SESSION   
   session.setAttribute("code", code);
   // 图象生效   
   g.dispose();   
   // 输出图象到页面   
   ImageIO.write(image, "JPEG", response.getOutputStream());
   //加上下面代码,运行时才不会出现java.lang.IllegalStateException: getOutputStream() has already been called ..........等异常
   response.getOutputStream().flush();  
   response.getOutputStream().close();  
   response.flushBuffer();  
   out.clear();  
   out = pageContext.pushBody(); 
%>

?3. 验证码检查页面(check.jsp:检查验证码是否输入正确)

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>验证</title>
<script type="text/javascript">
	function same(){
		loginForm.action = "login/login_login";
		loginForm.submit();
	}
	function different(){
		alert("请输入正确的验证码");
		location.href = "login.jsp";
	}
</script>
</head>
<body>
	<%
	String userName = request.getParameter("userName");
	String password = request.getParameter("userPwd");
	%>
	<form id="loginForm" name="loginForm" method="post">
		<input type="hidden" id="userName" value=<%=userName %>  name="user.userName">
		<input type="hidden" id="userPwd" value=<%=password %> name="user.userPwd">
	</form>
	<%
		String rand = session.getAttribute("code").toString();
		String input = request.getParameter("code");
		if(rand.equals(input)){
			out.println("<script language='javascript'>same();</script>");
		}else{
			out.print("<script language='javascript'>different();</script>");
		}
	%>
	
</body>
</html>

?

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