Java生成验证码小工具

无意中看到一个生成简易验证码的小工具类（保存学习）：

工具类代码：

 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", "华文新魏", "华文隶书", "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 ~ 28
         return new Font(fontName, style, size);
     }

     // 画干扰线
     private void drawLine (BufferedImage image) {
         int num  = 5;//一共画5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(randomColor()); //随机生成干扰线颜色
             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
     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.text
         drawLine(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);
     }
 }

测试代码：

import java.awt.image.BufferedImage;
import java.io.FileOutputStream;
import org.junit.Test;
public class Demo2 {
    @Test
    public void fun1() throws Exception {
        VerifyCode verifyCode = new VerifyCode();
        BufferedImage bi = verifyCode.getImage();
        System.out.println(verifyCode.getText());
        VerifyCode.output(bi, new FileOutputStream("F:/b.jpg"));
    }
}

运行结果：