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);

     }

 }

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"));

    }

}