验证码生成与应用-优快云博客

本文详细介绍了一个自定义的验证码生成工具类，包括字符集、颜色、字体等随机元素的设定，以及验证码图片的生成过程。同时，文章展示了如何通过Servlet将验证码发送到客户端，并在网页上实现验证码的显示和刷新功能。

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1.创建工具类

package cn.facta.common.util;

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

public class ImageVerifiCodeUtil {
	// 验证码字符集
	private static final char[] chars = { 
		'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 
		'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'm', 'n',
		'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
		'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'M', 'N', 
		'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'};
	//字体样式
	private static String [] CODETYPE = {"TimesRoman","Courier","Arial","宋体","仿宋","微软雅黑","Monospaced ","TimesRoman","Courier","Arial"};
	// 字符数量
	private static final int SIZE = 4;
	// 干扰线数量
	private static final int LINES = 5;
	// 宽度
	private static final int WIDTH = 85;
	// 高度
	private static final int HEIGHT = 40;
	// 字体大小
	private static final int FONT_SIZE = 30;
	
	/**
	 * 生成随机验证码及图片
	 * Object[0]：验证码字符串；
	 * Object[1]：验证码图片。
	 */
	public static Object[] createImage() {
		StringBuffer sb = new StringBuffer();
		// 1.创建空白图片
		BufferedImage image = new BufferedImage(
			WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);
		// 2.获取图片画笔
		Graphics graphic = image.getGraphics();
		// 3.设置画布颜色
		graphic.setColor(new Color(114, 113, 113));//Color.LIGHT_GRAY
		// 4.绘制矩形背景
		graphic.fillRect(0, 0, WIDTH, HEIGHT);
		// 5.画随机字符
		Random ran = new Random();
		int [] randomNum = getRandomNum(SIZE);
		for (int i = 0; i <SIZE; i++) {
			// 取随机字符索引
			int n = ran.nextInt(chars.length);
			// 设置随机颜色
			graphic.setColor(getRandomColor());
			// 设置字体大小
			graphic.setFont(new Font(CODETYPE[randomNum[i]], Font.BOLD + Font.ITALIC, FONT_SIZE));
			// 画字符
			graphic.drawString(
				chars[n] + "", i * WIDTH / SIZE, HEIGHT*2/3);
			// 记录字符
			sb.append(chars[n]);
		}
		// 6.画干扰线
		for (int i = 0; i < LINES; i++) {
			// 设置随机颜色
			graphic.setColor(getRandomColor());
			// 随机画线
			graphic.drawLine(ran.nextInt(WIDTH), ran.nextInt(HEIGHT),
					ran.nextInt(WIDTH), ran.nextInt(HEIGHT));
		}
		// 7.返回验证码和图片
		return new Object[]{sb.toString(), image};
	}

	
	/**
	 * 随机取色
	 */
	public static Color getRandomColor() {
		Random ran = new Random();
		Color color = new Color(ran.nextInt(256), ran.nextInt(256), ran.nextInt(256));
		return color;
	}
	
	/**
	 * 生成随机数
	 * @param num
	 * @return
	 */
    private static int[] getRandomNum(int num) {
    	int [] randomNum = new int[num];
    	for(int i=0;i<num;i++) {
            int onlyrandomNum = (int) (Math.random()*10);
            randomNum[i] = onlyrandomNum;
        }
    	return randomNum;
    }
}

创建servlet

package cn.facta.common.servlet;

import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;

import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import cn.facta.common.util.ImageVerifiCodeUtil;
@WebServlet("/ImageVerifiCodeServlet")
public class ImageVerifiCodeServlet extends HttpServlet{

	private static final long serialVersionUID = 1L;

	public void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		//第一个参数是生成的验证码，第二个参数是生成的图片
		Object[] objs = ImageVerifiCodeUtil.createImage();
		//将验证码存入Session
		req.getSession().setAttribute("imageCode",objs[0]);
		//将图片输出给浏览器
		BufferedImage image = (BufferedImage) objs[1];
		resp.setContentType("image/png");
		OutputStream os = resp.getOutputStream();
		ImageIO.write(image, "png", os);
	}
	
}

运用到页面中

function change(){
	$("#image").attr("src","${pageContext.request.contextPath }/ImageVerifiCodeServlet?a=" + new Date().getTime());
}

 <div style="position: absolute; left: 1080px; top: 340px;">
          	<img src="${pageContext.request.contextPath }/ImageVerifiCodeServlet" id="image"></img>
	    	<a href="javascript:change()" style="color: white;">&nbsp;&nbsp;换一张</a>
 </div>

获取session中的验证码(按照自己方式的写)

public static final String IMAGE_VERIFI_CODE = "imageCode";
    
    public static String getImgCode(HttpServletRequest request){
		String code = "";
    	try {
			Object obj = request.getSession().getAttribute(IMAGE_VERIFI_CODE);
			if (obj != null) {
				code = obj.toString();
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
    	return code;
    }

java图片验证码