简单的JSP用户登陆页面

最新推荐文章于 2024-03-29 17:45:21 发布

原创最新推荐文章于 2024-03-29 17:45:21 发布 · 1.8k 阅读

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文章标签：

#jsp #random #javascript #string #input #user

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index.jsp

<%@ page contentType="text/html;charset=gb2312"%>
<html>

</head>

<body>

</body>

</html>

index_cl.jsp

<%@ page contentType="text/html;charset=gb2312"%>
<%@ include file="../conn.jsp"%>
<%
String User = request.getParameter("User");     //得到登录用户名
String Pwd = request.getParameter("Pwd");       //得到登录密码
String sCode = request.getParameter("VerifyCode"); //得到用户输入的验证码

String sql="select pass from admin where name='"+User+"'";
ResultSet rs=stmt.executeQuery(sql);
if(!sCode.equals(session.getAttribute("rand"))) //判断输入的验证码是否正确
{
out.println("<script LANGUAGE='javascript'>alert('验证码错误!!');history.go(-1);</script>");
}
else
{
if (rs.next())   //判断数据库是否存在此用户
{
  if (Pwd.equals(rs.getString("pass")))   //判断用户输入密码是否正确
  {
   session.setAttribute("name","User");
   response.sendRedirect("Admin_Main.jsp");
  }
  else
  {
   out.println("<script LANGUAGE='javascript'>alert('密码错误!!');history.go(-1);</script>");
  }
}
else
{
  out.println("<script LANGUAGE='javascript'>alert('用户名错误!!');history.go(-1);</script>");
}
}
rs.close();
stmt.close();
conn.close();

img.jsp

<%@ page contentType="image/jpeg" import="java.awt.*,java.awt.image.*,java.util.*,javax.imageio.*" %>
<%!
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);
}
%>
<%
//设置页面不缓存
response.setHeader("Pragma","No-cache");
response.setHeader("Cache-Control","no-cache");
response.setDateHeader("Expires", 0);

// 在内存中创建图象
int width=60, 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));

//画边框
//g.setColor(new Color());
//g.drawRect(0,0,width-1,height-1);

// 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(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)));//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);

// 图象生效
g.dispose();

// 输出图象到页面
ImageIO.write(image, "JPEG", response.getOutputStream());