VerifyCode.java:

  1 package com.xjs.image;

  2 

  3 import java.awt.BasicStroke;

  4 import java.awt.Color;

  5 import java.awt.Font;

  6 import java.awt.Graphics2D;

  7 import java.awt.image.BufferedImage;

  8 import java.io.IOException;

  9 import java.io.OutputStream;

 10 import java.util.Random;

 11 

 12 import javax.imageio.ImageIO;

 13 

 14 public class VerifyCode {

 15     private int w = 70;

 16     private int h = 35;

 17      private Random r = new Random();

 18      // {"宋体", "华文楷体", "黑体", "华文新魏", "华文隶书", "微软雅黑", "楷体_GB2312"}

 19     private String[] fontNames  = {"宋体", "华文楷体", "黑体", "微软雅黑", "楷体_GB2312"};

 20     // 可选字符

 21     private String codes  = "23456789abcdefghjkmnopqrstuvwxyzABCDEFGHJKMNPQRSTUVWXYZ";

 22     // 背景色

 23     private Color bgColor  = new Color(255, 255, 255);

 24     // 验证码上的文本

 25     private String text ;

 26     

 27     // 生成随机的颜色

 28     private Color randomColor () {

 29         int red = r.nextInt(150);

 30         int green = r.nextInt(150);

 31         int blue = r.nextInt(150);

 32         return new Color(red, green, blue);

 33     }

 34     

 35     // 生成随机的字体

 36     private Font randomFont () {

 37         int index = r.nextInt(fontNames.length);

 38         String fontName = fontNames[index];//生成随机的字体名称

 39         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)

 40         int size = r.nextInt(5) + 24; //生成随机字号, 24 ~ 28

 41         return new Font(fontName, style, size);

 42     }

 43     

 44     // 画干扰线

 45     private void drawLine (BufferedImage image) {

 46         int num  = 3;//一共画3条

 47         Graphics2D g2 = (Graphics2D)image.getGraphics();

 48         for(int i = 0; i < num; i++) {//生成两个点的坐标，即4个值

 49             int x1 = r.nextInt(w);

 50             int y1 = r.nextInt(h);

 51             int x2 = r.nextInt(w);

 52             int y2 = r.nextInt(h); 

 53             g2.setStroke(new BasicStroke(1.5F)); 

 54             g2.setColor(Color.BLUE); //干扰线是蓝色

 55             g2.drawLine(x1, y1, x2, y2);//画线

 56         }

 57     }

 58     

 59     // 随机生成一个字符

 60     private char randomChar () {

 61         int index = r.nextInt(codes.length());

 62         return codes.charAt(index);

 63     }

 64     

 65     // 创建BufferedImage

 66     private BufferedImage createImage () {

 67         BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB); 

 68         Graphics2D g2 = (Graphics2D)image.getGraphics(); 

 69         g2.setColor(this.bgColor);

 70         g2.fillRect(0, 0, w, h);

 71          return image;

 72     }

 73     

 74     // 调用这个方法得到验证码

 75     public BufferedImage getImage () {

 76         BufferedImage image = createImage();//创建图片缓冲区 

 77         Graphics2D g2 = (Graphics2D)image.getGraphics();//得到绘制环境

 78         StringBuilder sb = new StringBuilder();//用来装载生成的验证码文本

 79         // 向图片中画4个字符

 80         for(int i = 0; i < 4; i++)  {//循环四次，每次生成一个字符

 81             String s = randomChar() + "";//随机生成一个字母 

 82             sb.append(s); //把字母添加到sb中

 83             float x = i * 1.0F * w / 4; //设置当前字符的x轴坐标

 84             g2.setFont(randomFont()); //设置随机字体

 85             g2.setColor(randomColor()); //设置随机颜色

 86             g2.drawString(s, x, h-5); //画图

 87         }

 88         this.text = sb.toString(); //把生成的字符串赋给了this.text

 89         drawLine(image); //添加干扰线

 90         return image;        

 91     }

 92     

 93     // 返回验证码图片上的文本

 94     public String getText () {

 95         return text;

 96     }

 97     

 98     // 保存图片到指定的输出流

 99     public static void output (BufferedImage image, OutputStream out) 

100                 throws IOException {

101         ImageIO.write(image, "JPEG", out);

102     }

103 }

测试：

 1 import java.awt.image.BufferedImage;

 2 import java.io.FileNotFoundException;

 3 import java.io.FileOutputStream;

 4 import java.io.IOException;

 5 

 6 import org.junit.Test;

 7 

 8 public class Demo {

 9     @Test

10     public void fun1() throws FileNotFoundException, IOException{

11         VerifyCode vc=new VerifyCode();

12         BufferedImage bi=vc.getImage();//得到验证码图片，是一个BufferedImage类型的

13         VerifyCode.output(bi, new FileOutputStream("F://VerifyCode.jpg"));

14         

15         System.out.println(vc.getText());

16     }

17 }

运行后会在指定文件路径下生成一张图片，以及在控制台打印图片上的文本。