S2SH验证码登录实现。

package org.verify.util; import java.awt.Color; import java.awt.Font; import java.awt.Graphics; import java.awt.image.BufferedImage; import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.util.Random; import javax.imageio.ImageIO; import javax.imageio.stream.ImageOutputStream; public class RandomNumUtil { public static final char[] CHARS = {'0','1','2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J', 'K', 'L', 'M', 'N', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z' }; private ByteArrayInputStream image;//图像 private String str;//验证码 //构造函数 private RandomNumUtil(){ init(); //初始化属性 } /** * 获得RandomNumUtil实例 */ public static RandomNumUtil Instance() { return new RandomNumUtil(); } /** * 获得图片验证图片 */ public ByteArrayInputStream getImage() { return image; } public void setImage(ByteArrayInputStream image) { this.image = image; } /** * 获得图片验证码 * @return */ public String getStr() { return str; } public void setStr(String str) { this.str = str; } /** * 初始化 */ private void init() { //在内存中创建图像 int width=65,height=20; BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); //获取图形上下文 Graphics g = image.getGraphics(); //生产随机类 Random random = new Random(); //设定背景色 g.setColor(getRandColor(200,250)); g.fillRect(0, 0, width, height); //设定字体 g.setFont(new Font("Times New Roman", Font.PLAIN, 18)); // 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(width); int y = random.nextInt(height); int xl = random.nextInt(12); int yl = random.nextInt(12); g.drawLine(x, y, x + xl, y + yl); } // 取随机产生的认证码(6位数字) StringBuffer sRand = new StringBuffer(); for (int i = 0; i < 4; i++) { String rand = String.valueOf(CHARS[random.nextInt(CHARS.length)]); sRand.append(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); } // 赋值验证码 this.str = sRand.toString(); // 图象生效 g.dispose(); ByteArrayInputStream input = null; ByteArrayOutputStream output = new ByteArrayOutputStream(); try { ImageOutputStream imageOut = ImageIO .createImageOutputStream(output); ImageIO.write(image, "JPEG", imageOut); imageOut.close(); input = new ByteArrayInputStream(output.toByteArray()); } catch (Exception e) { System.out.println("验证码图片产生出现错误：" + e.toString()); } this.image = input;/* 赋值图像 */ } /* * 给定范围获得随机颜色 */ 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); } }