• Jsp页面实现验证码


     1 <%@ page language="java" contentType="text/html; charset=UTF-8"
     2     pageEncoding="UTF-8"%>
     3 <%@ page import="java.util.Random"%>
     4 <%@ page import="java.io.OutputStream"%>
     5 <%@ page import="java.awt.Color"%>
     6 <%@ page import="java.awt.Font"%>
     7 <%@ page import="java.awt.Graphics"%>
     8 <%@ page import="java.awt.image.BufferedImage"%>
     9 <%@ page import="javax.imageio.ImageIO"%>
    10 <%
    11     int width = 60;
    12     int height = 32;
    13     //create the image
    14     BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
    15     Graphics g = image.getGraphics();
    16     // set the background color
    17     g.setColor(new Color(0xDCDCDC));
    18     g.fillRect(0, 0, width, height);
    19     // draw the border
    20     g.setColor(Color.black);
    21     g.drawRect(0, 0, width - 1, height - 1);
    22     // create a random instance to generate the codes
    23     Random rdm = new Random();
    24     String hash1 = Integer.toHexString(rdm.nextInt());
    25     System.out.print(hash1);
    26     // make some confusion
    27     for (int i = 0; i < 50; i++) {
    28         int x = rdm.nextInt(width);
    29         int y = rdm.nextInt(height);
    30         g.drawOval(x, y, 0, 0);
    31     }
    32     // generate a random code
    33     String capstr = hash1.substring(0, 4);
    34     //将生成的验证码存入session
    35     session.setAttribute("validateCode", capstr);
    36     g.setColor(new Color(0, 100, 0));
    37     g.setFont(new Font("Candara", Font.BOLD, 24));
    38     g.drawString(capstr, 8, 24);
    39     g.dispose();
    40     //输出图片
    41     response.setContentType("image/jpeg");
    42     out.clear();
    43     out = pageContext.pushBody();
    44     OutputStream strm = response.getOutputStream();
    45     ImageIO.write(image, "jpeg", strm);
    46     strm.close();
    47 %>
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  • 原文地址:https://www.cnblogs.com/mlsq2015/p/5553032.html
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