jsp中的验证码

做web开发，很多时间需要大量生成难证码，写一个验证码是一件很容易的事，但是写得好不会是一件易事。

以下是我写的一个验证码生成方法，经改进行，性能比初时(我第一次写时)被时提升了40%以上，仅供参考。

Java代码
import java.awt.Color;  
import java.awt.Font;  
import java.awt.Graphics;  
import java.awt.image.BufferedImage;  
import java.util.Random;  
 
import javax.imageio.ImageIO;  
import javax.servlet.ServletOutputStream;  
import javax.servlet.http.HttpServletRequest;  
import javax.servlet.http.HttpServletResponse;  
 
/** 
* 该方法主要是生成验证码,并返4位回验证码 
*  
* @author Jacky * 
*/ 
public final class ImageCode {  
 
    /** 
     * 经常用到的作静态常量处理，这样会加快处理速度，减少变量第次都要生成的内存空间浪费，用final使程序不用录找该类是否被继承，减少加载时间 
     *  
     */ 
 
    private static final Random random = new Random();  
 
    // 预定义定义四种字体，并将随机得到  
    private static final Font[] CODEFONT = { new Font("宋体", Font.BOLD, 25), new Font("宋体", Font.BOLD, 25), new Font("宋体", Font.BOLD, 25),  
            new Font("宋体", Font.BOLD, 25) };  
 
    // 预定义定义字体颜色，并将随机得到色  
    private static final Color[] FONTCOLOR = { Color.ORANGE, Color.RED, Color.PINK, Color.BLUE, Color.GREEN };  
 
    // 预定义 图片的背景颜色，并将随机得到  
    private static final Color[] BGCOLOR = { Color.BLACK, Color.WHITE };  
 
    // 预定义干扰线的颜色  
    private static final Color LINECOLOR = new Color(242, 234, 22);  
 
    // 预定义生随机的字符，用数组取值比String类型取一个值快  
    private static final String[] CODE = { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M",  
            "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z" };  
 
    // 返回的验证码  
    private static StringBuffer CONDENUMBER = null;  
 
    // 预定义图片大小  
    private static final int WIDTH = 100, HEIGHT = 25;  
 
    /** 
     * 生成验证码输出，并输出 
     *  
     * @param request 
     * @param response 
     * @return codeNumber 
     */ 
    public final String image(HttpServletRequest request, HttpServletResponse response) {  
        CONDENUMBER = new StringBuffer();  
        BufferedImage image = new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);  
        Graphics g = image.getGraphics();  
        g.setColor(BGCOLOR[random.nextInt(2)]);  
        g.fillRect(0, 0, WIDTH, HEIGHT);  
        for (int i = 0; i < 4; i++) {  
            drawCode(g, i);  
        }  
        drawNoise(g,;  
        g.setColor(Color.gray);  
        g.drawRect(0, 0, WIDTH - 1, HEIGHT - 1);  
        g.dispose();  
        response.setHeader("Pragma", "No-cache");  
        response.setHeader("Cache-Control", "no-cache");  
        response.setDateHeader("Expires", 0);  
        response.setContentType("image/png");  
        ServletOutputStream sos = null;  
        try {  
            sos = response.getOutputStream();  
            ImageIO.write(image, "png", sos);  
            sos.flush();  
            sos.close();  
        } catch (Exception e) {  
            e.printStackTrace();  
            return null;  
        }  
        return CONDENUMBER.toString();  
    }  
 
    /** 
     * 画验证码 
     *  
     * @param request 
     * @param response 
     * @return void 
     */ 
    private final void drawCode(Graphics graphics, int i) {  
        String number = CODE[random.nextInt(36)];  
        graphics.setFont(CODEFONT[random.nextInt(4)]);  
        graphics.setColor(FONTCOLOR[random.nextInt(5)]);  
        graphics.drawString(number, 10 + i * 20, 20);  
        CONDENUMBER.append(number);  
    }  
 
    /** 
     * 画干扰线 
     *  
     * @param graphics 
     * @param void 
     */ 
    private final void drawNoise(Graphics graphics, int lineNumber) {  
        graphics.setColor(LINECOLOR);  
        int pointX1, pointY1, pointX2, pointY2;  
        for (int i = 0; i < lineNumber; i++) {  
            pointX1 = 1 + (int) (Math.random() * WIDTH);  
            pointY1 = 1 + (int) (Math.random() * HEIGHT);  
            pointX2 = 1 + (int) (Math.random() * WIDTH);  
            pointY2 = 1 + (int) (Math.random() * HEIGHT);  
            graphics.drawLine(pointX1, pointY1, pointX2, pointY2);  
        }  
    }  
 
} 

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

import javax.imageio.ImageIO;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
* 该方法主要是生成验证码,并返4位回验证码
*
* @author Jacky *
*/
public final class ImageCode {

/**
* 经常用到的作静态常量处理，这样会加快处理速度，减少变量第次都要生成的内存空间浪费，用final使程序不用录找该类是否被继承，减少加载时间
*
*/

private static final Random random = new Random();

// 预定义定义四种字体，并将随机得到
private static final Font[] CODEFONT = { new Font("宋体", Font.BOLD, 25), new Font("宋体", Font.BOLD, 25), new Font("宋体", Font.BOLD, 25),
new Font("宋体", Font.BOLD, 25) };

// 预定义定义字体颜色，并将随机得到色
private static final Color[] FONTCOLOR = { Color.ORANGE, Color.RED, Color.PINK, Color.BLUE, Color.GREEN };

// 预定义 图片的背景颜色，并将随机得到
private static final Color[] BGCOLOR = { Color.BLACK, Color.WHITE };

// 预定义干扰线的颜色
private static final Color LINECOLOR = new Color(242, 234, 22);

// 预定义生随机的字符，用数组取值比String类型取一个值快
private static final String[] CODE = { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M",
"N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z" };

// 返回的验证码
private static StringBuffer CONDENUMBER = null;

// 预定义图片大小
private static final int WIDTH = 100, HEIGHT = 25;

/**
* 生成验证码输出，并输出
*
* @param request
* @param response
* @return codeNumber
*/
public final String image(HttpServletRequest request, HttpServletResponse response) {
CONDENUMBER = new StringBuffer();
BufferedImage image = new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);
Graphics g = image.getGraphics();
g.setColor(BGCOLOR[random.nextInt(2)]);
g.fillRect(0, 0, WIDTH, HEIGHT);
for (int i = 0; i < 4; i++) {
drawCode(g, i);
}
drawNoise(g,;
g.setColor(Color.gray);
g.drawRect(0, 0, WIDTH - 1, HEIGHT - 1);
g.dispose();
response.setHeader("Pragma", "No-cache");
response.setHeader("Cache-Control", "no-cache");
response.setDateHeader("Expires", 0);
response.setContentType("image/png");
ServletOutputStream sos = null;
try {
sos = response.getOutputStream();
ImageIO.write(image, "png", sos);
sos.flush();
sos.close();
} catch (Exception e) {
e.printStackTrace();
return null;
}
return CONDENUMBER.toString();
}

/**
* 画验证码
*
* @param request
* @param response
* @return void
*/
private final void drawCode(Graphics graphics, int i) {
String number = CODE[random.nextInt(36)];
graphics.setFont(CODEFONT[random.nextInt(4)]);
graphics.setColor(FONTCOLOR[random.nextInt(5)]);
graphics.drawString(number, 10 + i * 20, 20);
CONDENUMBER.append(number);
}

/**
* 画干扰线
*
* @param graphics
* @param void
*/
private final void drawNoise(Graphics graphics, int lineNumber) {
graphics.setColor(LINECOLOR);
int pointX1, pointY1, pointX2, pointY2;
for (int i = 0; i < lineNumber; i++) {
pointX1 = 1 + (int) (Math.random() * WIDTH);
pointY1 = 1 + (int) (Math.random() * HEIGHT);
pointX2 = 1 + (int) (Math.random() * WIDTH);
pointY2 = 1 + (int) (Math.random() * HEIGHT);
graphics.drawLine(pointX1, pointY1, pointX2, pointY2);
}
}

}

一个调用的例子：

Java代码
public void image(HttpServletRequest request, HttpServletResponse response) {  
        ImageCode ic = new ImageCode();  
        String imageCode = ic.image(request, response);  
        request.getSession().removeAttribute("imageCode");  
                  //转为小写，从页面输入也转为小写，以达到不分大小写作用  
        request.getSession().setAttribute("imageCode", imageCode.toLowerCase());  
    } 

public void image(HttpServletRequest request, HttpServletResponse response) {
ImageCode ic = new ImageCode();
String imageCode = ic.image(request, response);
request.getSession().removeAttribute("imageCode");
                  //转为小写，从页面输入也转为小写，以达到不分大小写作用
request.getSession().setAttribute("imageCode", imageCode.toLowerCase());
}

评论

2 楼 villain564 2009-11-17  

 

1 楼 villain564 2009-11-17  

drawNoise(g,8);