验证码(一)

最新推荐文章于 2022-08-12 18:19:23 发布

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最新推荐文章于 2022-08-12 18:19:23 发布

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分类专栏： servlet 文章标签： Java JSP Cache HTML

本文链接：https://blog.youkuaiyun.com/web_net/article/details/83532198

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[b]Pair.java[/b]

public class Pair<K, E> {
	private K key;
	private E value;

	public Pair() {
	}

	public Pair(K key, E value) {
		this.key = key;
		this.value = value;
	}

	public K getKey() {
		return key;
	}

	public void setKey(K key) {
		this.key = key;
	}

	public E getValue() {
		return value;
	}

	public void setValue(E value) {
		this.value = value;
	}
}

[b]ImageOut.java[/b]

import java.awt.Color;  
import java.awt.Font;  
import java.awt.Graphics2D;  
import java.awt.image.BufferedImage;  
import java.util.Random;  

public class ImageOut {  

    private static final int WIDTH = 62;  
    private static final int HEIGHT = 20;  

    private static Color getRandomColor() {  
        Random random = new Random();  
        return new Color(50 + random.nextInt(100), 50 + random.nextInt(100),  
                50 + random.nextInt(100));  
    }  

    private static int getRandomBgInt() {  
        Random random = new Random();  
        return 180 + random.nextInt(60);  
    }  

    private static Font getRandomFont() {  
        Random random = new Random();  
        return new Font("Times New Roman", Font.PLAIN, 10 + random.nextInt(8));  
    }  

    public static char getRandomChar() {  
        Random random = new Random();  
        if (random.nextInt(6) < 3) {  
            return (char) (65 + random.nextInt(26));  
        }  
        if(random.nextInt(6) < 3){
        	 return (char) (48 + random.nextInt(10)); 
        }
        return (char) (97 + random.nextInt(26));  
    }  

    public static Pair<String, BufferedImage> getImage() {  

        BufferedImage image = new BufferedImage(WIDTH, HEIGHT,  
                BufferedImage.TYPE_INT_RGB);  
        Graphics2D g = image.createGraphics();  
        g.setColor(new Color(255, getRandomBgInt(), 255));  
        g.fillRect(0, 0, WIDTH, HEIGHT);  
        StringBuilder s = new StringBuilder();  
        for (int i = 0; i < 4; i++) {  
            String t = String.valueOf(getRandomChar());  
            s.append(t);  
            g.setColor(getRandomColor());  
            g.setFont(getRandomFont());  
            g.drawString(t, 3 + 16 * i, 18);  
        }  
        g.dispose();  
        return new Pair<String, BufferedImage>(s.toString(), image);  
    }  
}

[b]validateImage.jsp[/b]

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<%@page import="java.awt.image.BufferedImage,javax.imageio.ImageIO" %>
<%@page import="com.lhz.util.Pair,com.lhz.util.ImageOut" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
    "http://www.w3.org/TR/html4/loose.dtd">
<%
            response.setContentType("image/jpeg");
            response.setHeader("Pragma", "No-cache");
            response.setHeader("Cache-Control", "no-cache");
            response.setDateHeader("Expires", 0);
            Pair<String, BufferedImage> p = ImageOut.getImage();
            ImageIO.write(p.getValue(), "JPEG", response.getOutputStream());
            out.clear();
			out = pageContext.pushBody();
            session.setAttribute("valid", p.getKey());
%>

[b]login.jsp[/b]


<script type="text/javascript">
			function changeValidateCode(obj) {
				var timenow = new Date().getTime();
				obj.src = "<%=path%>/validateImage.jsp?d=" + timenow;
			}
</script>

<td>
			<span style="color: red;">*</span>验证码
</td>
<td>
  <input style="ime-mode: disabled" class="inputValidate" type="text" name="yanzhm" />
  <img alt="看不清？单击更换！" src="<%=path%>/validateImage.jsp" onclick="changeValidateCode(this)" />
</td>