获取随机验证码代码

package cn.hk.image;import java.awt.BasicStroke;import java.awt.Color;import java.awt.Font;import java.awt.Graphics2D;import java.awt.image.BufferedImage;import java.io.IOException;import java.io.OutputStream;import java.util.Random;import javax.imageio.ImageIO;public class VerifyCode {private int w = 70;private int h = 35; private Random r = new Random(); // {"宋体", "华文楷体", "黑体", "华文新魏", "华文隶书", "微软雅黑", "楷体_GB2312"}private String[] fontNames  = {"宋体", "华文楷体", "黑体", "微软雅黑", "楷体_GB2312"};// 可选字符private String codes  = "23456789abcdefghjkmnopqrstuvwxyzABCDEFGHJKMNPQRSTUVWXYZ";// 背景色private Color bgColor  = new Color(255, 255, 255);// 验证码上的文本private String text ;// 生成随机的颜色private Color randomColor () {int red = r.nextInt(150);int green = r.nextInt(150);int blue = r.nextInt(150);return new Color(red, green, blue);}// 生成随机的字体private Font randomFont () {int index = r.nextInt(fontNames.length);String fontName = fontNames[index];//生成随机的字体名称int style = r.nextInt(4);//生成随机的样式, 0(无样式), 1(粗体), 2(斜体), 3(粗体+斜体)int size = r.nextInt(5) + 24; //生成随机字号, 24 ~ 28return new Font(fontName, style, size);}// 画干扰线private void drawLine (BufferedImage image) {int num  = 3;//一共画3条Graphics2D g2 = (Graphics2D)image.getGraphics();for(int i = 0; i < num; i++) {//生成两个点的坐标，即4个值int x1 = r.nextInt(w);int y1 = r.nextInt(h);int x2 = r.nextInt(w);int y2 = r.nextInt(h); g2.setStroke(new BasicStroke(1.5F)); g2.setColor(Color.BLUE); //干扰线是蓝色g2.drawLine(x1, y1, x2, y2);//画线}}// 随机生成一个字符private char randomChar () {int index = r.nextInt(codes.length());return codes.charAt(index);}// 创建BufferedImage，图片缓存区private BufferedImage createImage () {BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB); Graphics2D g2 = (Graphics2D)image.getGraphics(); g2.setColor(this.bgColor);g2.fillRect(0, 0, w, h); return image;}// 调用这个方法得到验证码public BufferedImage getImage () {BufferedImage image = createImage();//创建图片缓冲区 Graphics2D g2 = (Graphics2D)image.getGraphics();//得到绘制环境StringBuilder sb = new StringBuilder();//用来装载生成的验证码文本// 向图片中画4个字符for(int i = 0; i < 4; i++)  {//循环四次，每次生成一个字符String s = randomChar() + "";//随机生成一个字母 sb.append(s); //把字母添加到sb中float x = i * 1.0F * w / 4; //设置当前字符的x轴坐标g2.setFont(randomFont()); //设置随机字体g2.setColor(randomColor()); //设置随机颜色g2.drawString(s, x, h-5); //画图}this.text = sb.toString(); //把生成的字符串赋给了this.textdrawLine(image); //添加干扰线return image;}// 返回验证码图片上的文本public String getText () {return text;}// 保存图片到指定的输出流public static void output (BufferedImage image, OutputStream out) throws IOException {ImageIO.write(image, "JPEG", out);}}