Java生成随机验证码图片并进行Base64编码

package com.pohoocredit.profitcard.backend.utils;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Arrays;
import java.util.Random;

import javax.imageio.ImageIO;

import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

/**
* 图片验证码随机生成后，并进行base64转换，也可将base64图片字符串转换为图片生成
*/
public class RandomImgCodeUtil {
private static Random random = new Random();

private static Color getRandColor(int fc, int bc) {
if (fc > 255)
fc = 255;
if (bc > 255)
bc = 255;
int r = fc + random.nextInt(bc - fc);
int g = fc + random.nextInt(bc - fc);
int b = fc + random.nextInt(bc - fc);
return new Color(r, g, b);
}

private static int getRandomIntColor() {
int[] rgb = getRandomRgb();
int color = 0;
for (int c : rgb) {
color = color << 8;
color = color | c;
}
return color;
}

private static int[] getRandomRgb() {
int[] rgb = new int[3];
for (int i = 0; i < 3; i++) {
rgb[i] = random.nextInt(255);
}
return rgb;
}

private static void shear(Graphics g, int w1, int h1, Color color) {
shearX(g, w1, h1, color);
shearY(g, w1, h1, color);
}

private static void shearX(Graphics g, int w1, int h1, Color color) {

int period = random.nextInt(2);

boolean borderGap = true;
int frames = 1;
int phase = random.nextInt(2);

for (int i = 0; i < h1; i++) {
double d = (double) (period >> 1)
* Math.sin((double) i / (double) period + (6.2831853071795862D * (double) phase) / (double) frames);
g.copyArea(0, i, w1, 1, (int) d, 0);
if (borderGap) {
g.setColor(color);
g.drawLine((int) d, i, 0, i);
g.drawLine((int) d + w1, i, w1, i);
}
}

}

private static void shearY(Graphics g, int w1, int h1, Color color) {

int period = random.nextInt(40) + 10; // 50;

boolean borderGap = true;
int frames = 20;
int phase = 7;
for (int i = 0; i < w1; i++) {
double d = (double) (period >> 1)
* Math.sin((double) i / (double) period + (6.2831853071795862D * (double) phase) / (double) frames);
g.copyArea(i, 0, 1, h1, 0, (int) d);
if (borderGap) {
g.setColor(color);
g.drawLine(i, (int) d, i, 0);
g.drawLine(i, (int) d + h1, i, h1);
}

}
}

/**
* 生成指定长度的随机数字和字母
* @param length
* @return
*/
public static String getStringRandom(int length) {
String val = "";
Random random = new Random();
for (int i = 0; i < length; i++) {
String charOrNum = random.nextInt(2) % 2 == 0 ? "char" : "num";
switch (charOrNum) {
case "char":
int temp = random.nextInt(2) % 2 == 0 ? 65 : 97;
val += (char) (random.nextInt(26) + temp);
break;
case "num":
val += String.valueOf(random.nextInt(10));
break;
}
}
return val;
}

/**
* Base64编码的验证码图片
* @param w
* @param h
* @param code
* @return
* @throws Exception
*/
public static String imageToBase64(int w, int h, String code) throws Exception {
int verifySize = code.length();
BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
Random rand = new Random();
Graphics2D g2 = image.createGraphics();
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
Color[] colors = new Color[5];
Color[] colorSpaces = new Color[] { Color.WHITE, Color.CYAN, Color.GRAY, Color.LIGHT_GRAY, Color.MAGENTA,
Color.ORANGE, Color.PINK, Color.YELLOW };
float[] fractions = new float[colors.length];
for (int i = 0; i < colors.length; i++) {
colors[i] = colorSpaces[rand.nextInt(colorSpaces.length)];
fractions[i] = rand.nextFloat();
}
Arrays.sort(fractions);

g2.setColor(Color.GRAY);// 设置边框色
g2.fillRect(0, 0, w, h);

Color c = getRandColor(200, 250);
g2.setColor(c);// 设置背景色
g2.fillRect(0, 2, w, h - 4);

// 绘制干扰线
Random random = new Random();
g2.setColor(getRandColor(160, 200));// 设置线条的颜色
for (int i = 0; i < 20; i++) {
int x = random.nextInt(w - 1);
int y = random.nextInt(h - 1);
int xl = random.nextInt(6) + 1;
int yl = random.nextInt(12) + 1;
g2.drawLine(x, y, x + xl + 40, y + yl + 20);
}

// 添加噪点
float yawpRate = 0.05f;// 噪声率
int area = (int) (yawpRate * w * h);
for (int i = 0; i < area; i++) {
int x = random.nextInt(w);
int y = random.nextInt(h);
int rgb = getRandomIntColor();
image.setRGB(x, y, rgb);
}

shear(g2, w, h, c);// 使图片扭曲

g2.setColor(getRandColor(100, 160));
int fontSize = h - 4;
Font font = new Font("Arial", Font.ITALIC, fontSize);
g2.setFont(font);
char[] chars = code.toCharArray();
for (int i = 0; i < verifySize; i++) {
AffineTransform affine = new AffineTransform();
affine.setToRotation(Math.PI / 4 * rand.nextDouble() * (rand.nextBoolean() ? 1 : -1),
(w / verifySize) * i + fontSize / 2, h / 2);
g2.setTransform(affine);
g2.drawChars(chars, i, 1, ((w - 10) / verifySize) * i + 5, h / 2 + fontSize / 2 - 10);
}
g2.dispose();
ByteArrayOutputStream baos = new ByteArrayOutputStream();
ImageIO.write(image, "jpg", baos);
return new BASE64Encoder().encode(baos.toByteArray());
}

/**
* 将Base64位编码的图片进行解码，并保存到指定目录
*
* @param base64
*            base64编码的图片信息
* @return
*/
public static void base64ToImage(String base64) {
BASE64Decoder decoder = new BASE64Decoder();
try {
File file = new File("D:/test.jpg");
FileOutputStream write = new FileOutputStream(file);
byte[] decoderBytes = decoder.decodeBuffer(base64);
write.write(decoderBytes);
write.close();
} catch (IOException e) {
e.printStackTrace();
}
}

public static void main(String[] args) throws Exception {
base64ToImage(imageToBase64(120, 40, getStringRandom(4)));
}
}