Java 类 生成图片验证码

Java 类 生成图片验证码

简单方便

package com.hyd.iae.util;

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

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

/**
 * 生成验证码
 * @author Administrator
 *
 */
@WebServlet("/verifyCode")
public class VerifyCode extends HttpServlet {

	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;
	// 图片的宽度。
	private int width = 100;
	// 图片的高度。
	private int height = 40;
	// 验证码字符个数
	private int codeCount = 4;
	// 验证码干扰线数
	private int lineCount = 150;

	@Override
	protected void service(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		response.setContentType("image/jpeg");
		// 设置页面不缓存
		response.setHeader("Pragma", "No-cache");
		response.setHeader("Cache-Control", "no-cache");
		response.setDateHeader("Expires", 0);
		// 在内存中创建图像
		BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
		// 获取图形上下文
		Graphics g = image.getGraphics();
		// 随机类
		Random random = new Random();
		// 设定背景
		g.setColor(getRandColor(200, 250));
		g.fillRect(0, 0, width, height);
		// 设定字体
		g.setFont(new Font("Times New Roman", Font.PLAIN, 30));
		// 随机产生干扰线
		g.setColor(getRandColor(160, 200));
		for (int i = 0; i < lineCount; i++) {
			int x = random.nextInt(width);
			int y = random.nextInt(height);
			int xl = random.nextInt(12);
			int yl = random.nextInt(12);
			g.drawLine(x, y, x + xl, y + yl);
		}
		// 随机产生4位验证码
		String[] codes = { "2", "3", "4", "5", "6", "7", "8", "9", "A", "B", "C", "D", "E", "F", "G", "H", "J", "K",
				"M", "N", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z", "a", "b", "c", "d", "e", "f", "g", "h",
				"j", "k", "m", "n", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z" };
		String code = "";
		for (int i = 0; i < codeCount; i++) {
			String str = codes[random.nextInt(codes.length)];
			code += str;
			// 将认证码显示到图象中
			g.setColor(new Color(50 + random.nextInt(110), 20 + random.nextInt(110), 30 + random.nextInt(110)));
			// 调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成
			g.drawString(str, 18 * i + 13, 27); // 文字间距*i+距离左边距，上边距
		}
		HttpSession session = request.getSession();
		// 将认证码存入SESSION
		session.setAttribute("code", code);
		// 图象生效
		g.dispose();
		// 输出图象到页面
		ImageIO.write(image, "JPEG", response.getOutputStream());
		// 加上下面代码,运行时才不会出现java.lang.IllegalStateException: getOutputStream() has
		// already been called ..........等异常
		response.getOutputStream().flush();
		response.getOutputStream().close();
		response.flushBuffer();
	}

	/**
	 * bc > fc
	 * 
	 * @param fc
	 * @param bc
	 * @return
	 */
	private Color getRandColor(int fc, int bc) {
		Random random = new Random();
		if (fc > 255)
			fc = 255;
		if (bc > 255)
			bc = 255;
		int r = fc + random.nextInt(bc - fc);
		int g = fc + random.nextInt(bc - fc);
		int b = fc + random.nextInt(bc - fc);
		return new Color(r, g, b);
	}

}

<img class="imgObj" alt="验证码" src="verifyCode" onclick="changeImg()" />

// 刷新图片
function changeImg() {
	var imgSrc = $(".imgObj");
	var src = imgSrc.attr("src");
	imgSrc.attr("src", changeUrl(src));
}
//为了使每次生成图片不一致，即不让浏览器读缓存，所以需要加上时间戳
function changeUrl(url) {
	var timestamp = (new Date()).valueOf();
	var index = url.indexOf("?", url);
	if(index > 0) {
		url = url.substring(0, url.indexOf(url, "?"));
	}
	if((url.indexOf("&") >= 0)) {
		url = url + "×tamp=" + timestamp;
	} else {
		url = url + "?timestamp=" + timestamp;
	}
	return "verifyCode?" + url;
}