jsp随机验证码生成测试

/** * */ package com.lideedu.randompic; import java.awt.Color; import java.awt.Font; import java.awt.Graphics; import java.awt.image.BufferedImage; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import java.io.OutputStream; import java.util.Random; import javax.imageio.ImageIO; /** * @author Administrator * */ public class RandomPic { Random random = new Random(); private OutputStream desc; public RandomPic(OutputStream desc) { this.desc=desc; } //返回的是生成的验证码 public String generate() throws IOException { BufferedImage image = new BufferedImage(60, 20,BufferedImage.TYPE_INT_RGB); // 获取图形上下文 Graphics g = image.getGraphics(); g.setColor(getRandColor(200, 250));//设置画笔颜色 g.fillRect(0, 0, 60, 20);//用该颜色填充整个画布 // 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到 g.setColor(getRandColor(160, 200)); for (int i = 0; i < 155; i++) { int x = random.nextInt(60); int y = random.nextInt(20); int xl = random.nextInt(12); int yl = random.nextInt(12); g.drawLine(x, y, x + xl, y + yl); } //设定字体 g.setFont(new Font("Times New Roman", Font.PLAIN, 18)); String sRand=""; for (int i = 0; i < 4; i++) { String rand = String.valueOf(random.nextInt(10)); sRand += rand; // 将认证码显示到图象中 g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + 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(rand, 13 * i + 6, 16); } g.dispose(); // 输出图象到文件 // 把存在于内存的bit点阵（pixel)，按JPEG格式压缩存盘 ImageIO.write(image, "JPEG", desc); return sRand; } //给定范围获得随机颜色 private Color getRandColor(int fc, int bc) { 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); } }