JavaWeb基础—VerifyCode源码

 package com.jiangbei.verifycodeutils;

 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 ~ 28

 return 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

 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);

 }

 }

简单运用：

　　

 package com.day11.servlet;

 import java.awt.image.BufferedImage;
 import java.io.IOException;

 import javax.servlet.ServletException;
 import javax.servlet.http.HttpServlet;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;

 import com.jiangbei.verifycodeutils.VerifyCode;
 /**
  * 用于验证码案例
  * @author jiangbei01
  *
  */
 public class VerifyCodeServlet extends HttpServlet {

     public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
         /**
          * 生成图片
          * 保存图片上验证码文本到session域中
          * 将图片响应给客户端
          */
         VerifyCode vc = new VerifyCode();
         BufferedImage image = vc.getImage();
         request.getSession().setAttribute("vcode", vc.getText());

         VerifyCode.output(image, response.getOutputStream());

     }