用struts做一个有验证码的注册页面(适合新手)

package net.hncu.util; import java.awt.Color; import java.awt.Font; import java.awt.Graphics2D; import java.awt.image.BufferedImage; import java.io.File; import java.util.LinkedList; import java.util.Random; import javax.imageio.ImageIO; import javax.servlet.http.HttpServletResponse; import com.sun.image.codec.jpeg.JPEGCodec; import com.sun.image.codec.jpeg.JPEGImageEncoder; public class Yanzhengma { public String sRand = ""; public Yanzhengma() { } // 给定范围获得随机颜色 public 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); } //创建图像 格式为jpg类型,默认长和宽 public BufferedImage getBufferedImage(String content) { int width = 60, height = 20; return getBufferedImage(content, width, height); } //创建图像 格式为jpg类型，接受长和宽两个参数 public BufferedImage getBufferedImage(String content, int width, int height) { // 实例化BufferedImage BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); // 获取图形上下文 Graphics2D g = image.createGraphics(); // 生成随机类 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)); // 设置字体颜色 g.setColor(Color.black); g.drawString(content, 10, 15); g.dispose(); //返回图片 return image; } // 返回一个4位的验证码 public String getContent() throws InterruptedException { String content = ""; for (int i = 0; i < 4; i++) { content += getChar(); //利用 休眠以控制字符的重复问题 Thread.sleep(new Random().nextInt(10) + 10); } return content; } //获取随机字符 public char getChar() { Random random = new Random(); char ch = '0'; LinkedList ls = new LinkedList(); for (int i = 0; i < 10; i++) {// 0-9 ls.add(String.valueOf(48 + i)); } for (int i = 0; i < 26; i++) {// A-Z ls.add(String.valueOf(65 + i)); } for (int i = 0; i < 26; i++) {// a-z ls.add(String.valueOf(97 + i)); } int index = random.nextInt(ls.size()); if (index > (ls.size() - 1)) { index = ls.size() - 1; } ch = (char) Integer.parseInt(String.valueOf(ls.get(index))); return ch; } }