springmvc java的验证码的小程序

记录下自己的验证码小工具，留待以后复用。

字符库代码

public class SecurityCode {

    public enum SecurityCodeLevel {
        Simple, Medium, Hard
    };

    public static String getSecurityCode() {
        return getSecurityCode(4, SecurityCodeLevel.Medium, false);
    }

    public static String getSecurityCode(int length, SecurityCodeLevel level,
            boolean isCanRepeat) {
        // 随机抽取len个字符
        int len = length;
        // 字符集合(除去易混淆的数字0、数字1、字母l、字母o、字母O)
        char[] codes = { '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b',
                'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'm', 'n', 'p',
                'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 'A', 'B',
                'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N',
                'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z' };
        // 根据不同的难度截取字符数组
        if (level == SecurityCodeLevel.Simple) {
            codes = Arrays.copyOfRange(codes, 0, 9);
        } else if (level == SecurityCodeLevel.Medium) {
            codes = Arrays.copyOfRange(codes, 0, 33);
        }
        // 字符集合长度
        int n = codes.length;
        // 抛出运行时异常
        if (len > n && isCanRepeat == false) {
            throw new RuntimeException(
                    String.format(
                            "验证码长度大于字符库长度,请改小验证码位数参数 length",
                            len, level, isCanRepeat, n));
        }

        // 存放抽取出来的字符
        char[] result = new char[len];

        // 判断能否出现重复的字符
        if (isCanRepeat) {
            for (int i = 0; i < result.length; i++) {
                // 索引 0 and n-1
                int r = (int) (Math.random() * n);

                // 将result中的第i个元素设置为codes[r]存放的数值
                result[i] = codes[r];
            }
        } else {
            for (int i = 0; i < result.length; i++) {
                // 索引 0 and n-1
                int r = (int) (Math.random() * n);

                // 将result中的第i个元素设置为codes[r]存放的数值
                result[i] = codes[r];

                // 必须确保不会再次抽取到那个字符，因为所有抽取的字符必须不相同。
                // 因此，这里用数组中的最后一个字符改写codes[r]，并将n减1
                codes[r] = codes[n - 1];
                n--;
            }
        }
        return String.valueOf(result);
    }
}

画图片代码

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.Random;
import com.sun.image.codec.jpeg.ImageFormatException;
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;

public class SecurityImage {

    public static BufferedImage createImage(String securityCode) {

        // 验证码长度
        int codeLength = securityCode.length();
        // 字体大小
        int fSize = 15;
        int fWidth = fSize + 1;
        // 图片宽度
        int width = codeLength * fWidth + 6;
        // 图片高度
        int height = fSize * 2 + 1;

        // 图片
        BufferedImage image = new BufferedImage(width, height,
                BufferedImage.TYPE_INT_RGB);
        Graphics g = image.createGraphics();

        // 设置背景色
        g.setColor(Color.WHITE);
        // 填充背景
        g.fillRect(0, 0, width, height);

        // 设置边框颜色
        g.setColor(Color.LIGHT_GRAY);
        // 边框字体样式
        g.setFont(new Font("Arial", Font.BOLD, height - 2));
        // 绘制边框
        g.drawRect(0, 0, width - 1, height - 1);

        // 绘制噪点
        Random rand = new Random();
        for (int i = 0; i < codeLength * 6; i++) {
            int xs = rand.nextInt(width);
            int ys = rand.nextInt(height);
            // 绘制1*1大小的矩形
            randColor(g, rand);
            g.drawRect(xs, ys, 1, 1);

        }

        // 干扰线
        for (int i = 0; i < 10; i++) {
            int xs = rand.nextInt(width);
            int ys = rand.nextInt(height);
            int xe = xs + 10;
            int ye = ys + 10;
            randColor(g, rand);
            g.drawLine(xs, ys, xe, ye);
        }

        // 绘制验证码
        int codeY = height - 10;
        // 设置字体颜色和样式
        g.setFont(new Font("Georgia", Font.BOLD, fSize));
        for (int i = 0; i < codeLength; i++) {
            randColor(g, rand);
            g.drawString(String.valueOf(securityCode.charAt(i)), i * 16 + 5,
                    codeY);
        }
        // 关闭资源
        g.dispose();

        return image;
    }

    /**
     * 随机色
     * 
     * @param g
     * @param rand
     */
    private static void randColor(Graphics g, Random rand) {
        int red = 0, green = 0, blue = 0;
        red = rand.nextInt(255);
        green = rand.nextInt(255);
        blue = rand.nextInt(255);
        g.setColor(new Color(red, green, blue));
    }

    public static ByteArrayInputStream getImageAsInputStream(String securityCode) {

        BufferedImage image = createImage(securityCode);
        return convertImageToStream(image);
    }

    private static ByteArrayInputStream convertImageToStream(BufferedImage image) {

        ByteArrayInputStream inputStream = null;
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        JPEGImageEncoder jpeg = JPEGCodec.createJPEGEncoder(bos);
        try {
            jpeg.encode(image);
            byte[] bts = bos.toByteArray();
            inputStream = new ByteArrayInputStream(bts);
        } catch (ImageFormatException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return inputStream;
    }
}