java实现在注册登录的时候添加验证码

package com.yidongxueyuan.web.verifycode;

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;

/*
 *    随机生成一个验证码图片： 
 *    
 */
public class VerifyCode {
	private int w = 70;//设置缓冲区的宽
	private int h = 35;//设置缓冲区的宽
 	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"};
	//源
	private String codes  = "23456789abcdefghjkmnpqrstuvwxyzABCDEFGHJKMNPQRSTUVWXYZ";
	// 背景颜色
	private Color bgColor  = new Color(255, 255, 255);
	// 保存随机生成的图片当中的内容。
	private String text ;
	
	// 随机生成颜色
	private Color rand