Java 生成验证码

package com.lf.testvity;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.Robot;
import java.awt.image.BufferedImage;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Random;

import javax.imageio.ImageIO;
import javax.security.auth.message.callback.PrivateKeyCallback.Request;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import javax.sound.midi.Patch;

import org.junit.Test;

public class Vitiry {

    //验证码字符的个数
    private static int count = 4;
    //干扰线的条数
    private static int lines = 2;
    /**
     * 随机产生颜色
     * @return 颜色
     */
    private static Color getRandomColor(){
        Random random = new Random();
        Color color = new Color(random.nextInt(255)+1, random.nextInt(255)+1, random.nextInt(255)+1);
        return color;
    }
    /**
     * 获取四个字符的字符串
     * @return 字符串
     */
    public static String getForthWord() {
        String string = "23456789abcdefghijkmnpqrstuvwxyz";
        StringBuilder newStr = new StringBuilder("");
        //随机获取count个数字，根据count个随机数产生字符串
        Random random = new Random();
        for (int i = 0; i < count; i++) {
            int ranNum=random.nextInt(string.length());
            newStr.append(string.charAt(ranNum));
        }
        String str = new String(newStr);
        return str;
    }
    /**
     * 绘画验证码
     * @return BufferedImage
     */
    public static BufferedImage productImage() {

        int width = 70;
        int height = 30;
        // 得到图片缓存区
        BufferedImage bi = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);

        // 得到它的绘制环境（这张图片的笔）
        Graphics2D g2 = (Graphics2D)bi.getGraphics();

        // 设置颜色
        g2.setColor(Color.WHITE);
        // 填充整张图片(其实就是设置背景颜色)
        g2.fillRect(0, 0, width, height);
        // 设置字体
        g2.setFont(new Font("宋体", Font.BOLD, 25));
        //设置颜色
        g2.setColor(Vitiry.getRandomColor());
        // 向图片写字符串
        g2.drawString(Vitiry.getForthWord(), 7, 25);
        //画两条干扰线
        Random random = new Random();
        for (int i = 0; i < lines; i++) {
            g2.drawLine(2, random.nextInt(height-10)+10, width-5, random.nextInt(height));
        }

        return bi;
    }

}