Java 验证码工具类

时间：2022-10-15 15:18:59
package com.wuyu.util;

import java.awt.Color;

import java.awt.Font;

import java.awt.Graphics;

import java.awt.Graphics2D;

import java.awt.image.BufferedImage;

import java.io.IOException;

import java.util.Random;

import javax.imageio.ImageIO;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

/**

 * 验证码工具类

 * @author wuyu

 */

public class ValidateCode {

	public static final int WIDTH = 93;

	public static final int HEIGHT = 30;

	public static String getImageCode(HttpServletRequest request, HttpServletResponse response)

			throws ServletException, IOException {

		response.setContentType("text/html;charset=utf-8");

		// 创建缓存

		BufferedImage bi = new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);

		// 获得画布

		Graphics g = bi.getGraphics();

		// 设置背影色

		setBackGround(g);

		// 设置边框

		setBorder(g);

		// 写随机数

		String random = drawRandomNum((Graphics2D) g);

		// 将随机汉字存在session中

		// request.getSession().setAttribute("checkcode", random);

		// 将图形写给浏览器

		response.setContentType("image/jpeg");

		// 发头控制浏览器不要缓存

		response.setDateHeader("expries", -1);

		response.setHeader("Cache-Control", "no-cache");

		response.setHeader("Pragma", "no-cache");

		// 将图片写给浏览器

		ImageIO.write(bi, "jpg", response.getOutputStream());

		return random;

	}

	/**

	 * 设置背景色

	 *

	 * @param g

	 */

	private static void setBackGround(Graphics g) {

		// 设置颜色

		g.setColor(Color.WHITE);

		// 填充区域

		g.fillRect(0, 0, WIDTH, HEIGHT);

	}

	/**

	 * 设置边框

	 *

	 * @param g

	 */

	private static void setBorder(Graphics g) {

		// 边框区域

		g.drawRect(1, 1, WIDTH - 2, HEIGHT - 2);

	}

	/**

	 *

	 * @param g

	 * @return

	 */

	private static String drawRandomNum(Graphics2D g) {

		StringBuffer sb = new StringBuffer();

		// 设置颜色

		g.setColor(Color.RED);

		String[] code = { "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", "1", "2", "3", "4", "5", "6", "7", "8", "9", "0" };

		int x = 7;

		g.setFont(new Font("DEFAULT", Font.PLAIN, 24));

		// 控制字符数

		Random random = new Random();

		for (int i = 0; i < 4; i++) {

			// 设置字体旋转角度

			int degree = new Random().nextInt() % 30;

			// 截取\\

			String ch = code[random.nextInt(code.length)];

			sb.append(ch);

			// 正向角度

			g.rotate(degree * Math.PI / 180, x, 20);

			g.drawString(ch, x, 20);

			// 反向角度

			g.rotate(-degree * Math.PI / 180, x, 20);

			x += 20;

		}

		return sb.toString();

	}

}

　　调用getImageCode方法后，返回一个字符串，然后放入session中，就可以实现验证码的验证。

相关文章