登录功能  用户名zs 密码123 登录成功  

要求 有验证码功能  界面要美观

login.jsp

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>


<!DOCTYPE HTML >
<html>
  <head>
   
    
    <title>登录界面</title>
    <!--
    <link rel="stylesheet" type="text/css" href="styles.css">
    -->
    <style type="text/css"> 
    .contentArea{width:450px;position:absolute;top:80px;left:250px;height:500px;} 
    </style> 
  </head>
  
  <body  style="background:url(images/1.jpg)">
  <div class="contentArea">
  <p style="font-family:黑体；font-size:56；color：yellow"></p>
  登录<br/><br/><br/>
   <form action="dologin.jsp" name="myform" method="post" >
   用户名：<input type="text" name="uname"><br/><br/>
   密码：<input type="password" name="upwd"><br/>  <br/>
    验证码：<img src="yanzhengma.jsp"/>
          <input type="text" name="code"/>
          <br/><br/>
   <input type="submit" value="登录"><br/><br/><br/><br/>
   <a href="register.jsp" >进行注册</a>
   </form>
   
   </div>
  </body >
</html>

　　yanzhengma.jsp

<%@ page contentType="image/jpeg" language="java" import="java.util.*,java.awt.*,java.awt.image.*,javax.imageio.*" pageEncoding="utf-8"%>
 
<%!
    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-catch");
    response.setDateHeader("Expires",0);
 
    //在内存中创建图象
    int width = 60;
    int height = 20;
    BufferedImage image = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);
 
    //创建图象
    Graphics g = image.getGraphics();
    //生成随机对象
    Random random = new Random();
    //设置背景色
    g.setColor(getRandColor(200,250));
    g.fillRect(0,0,width,height);
    //设置字体
    g.setFont(new Font("Tines Nev Roman",Font.PLAIN,18));
    //随机产生干扰线
    g.setColor(getRandColor(160,200));
    for(int i = 0; i < 255; i++){
        int x = random.nextInt(width);
        int y = random.nextInt(height);
        int xl = random.nextInt(12);
        int yl = random.nextInt(12);
    }
    //随机产生认证码,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(110),20 + random.nextInt(110),20 + random.nextInt(110)));
        g.drawString(rand,13*i+6,16);
    }
    session.setAttribute("rCode",sRand);
    //图像生效
    g.dispose();
    //输出图像到页面
    ImageIO.write(image,"JPEG",response.getOutputStream());
    out.clear();
    out = pageContext.pushBody();
%>

　　dologin.jsp

<%@ page contentType="image/jpeg" language="java" import="java.util.*,java.awt.*,java.awt.image.*,javax.imageio.*" pageEncoding="utf-8"%>
 
<%
    //获取登录的用户名
    String name = request.getParameter("uname");
    //获取登录密码
    String pwd = request.getParameter("upwd");
    //判断
 
    if (name.equals("zs") && pwd.equals("123"))//判断字符串是否相等不是等号是eqyals
        //转发到ok页面
        request.getRequestDispatcher("ok.jsp").forward(request,response);
    else
        //转发到no页面
        request.getRequestDispatcher("login.jsp").forward(request,response);
%>