使用java实现验证码

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.OutputStream;
import java.util.Random;public class Dish2 {public static void main(String[] args) throws Exception {int width = 150;int height = 50;//在内存中生成图片BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);Graphics g = image.getGraphics();//绘制图片边框,fillrect是生成一个实心方框，drawrect是生成空心方框g.setColor(Color.CYAN);g.fillRect(0, 0, width, height);//width-1表示减少一个像素，这样才能使线条显示出来，不至于与背景重叠g.setColor(Color.BLUE);g.drawRect(0, 0, width - 1, height - 1);String str = "ABCDEFGHJKLMNOPQRSTUVWXYZabcdefgjklmnopqrstuvwxyz";Random random = new Random();saveString(width, height, str, random, g);saveLine(width, height, random, g);saveImage(image, "jpg", new FileOutputStream("D:\\javaDemo1\\demo\\a.jpg"));System.out.println("生成验证码成功！");}public static void saveImage(BufferedImage img, String jpg, OutputStream out) throws Exception {ImageIO.write(img, "JPEG", out);}//随机生成颜色private static Color getrandomColor(Random random) {int colorIndex = random.nextInt(4);switch (colorIndex) {case 0:return Color.BLUE;case 1:return Color.BLACK;case 2:return Color.GREEN;case 3:return Color.red;case 4:return Color.DARK_GRAY;default:return Color.YELLOW;}}//绘制验证码的字符private static void saveString(int width, int height, String str, Random random, Graphics graphics) {for (int i = 0; i < 4; i++) {//获取随机的字符int index = random.nextInt(str.length());char ch = str.charAt(index);//获取随机颜色Color color = getrandomColor(random);graphics.setColor(color);//设置字体Font font = new Font("宋体", Font.LAYOUT_NO_LIMIT_CONTEXT, height / 2);graphics.setFont(font);//写入验证码graphics.drawString(ch + "", (i == 0) ? width / 4 * i + 2 : width / 4 * i, height - height / 4);}}//绘制干扰线private static void saveLine(int width, int height, Random random, Graphics graphics) {Color lineColor = getrandomColor(random);for (int i = 0; i < 10; i++) {int x1 = random.nextInt(width);int x2 = random.nextInt(width);int y1 = random.nextInt(height);int y2 = random.nextInt(height);Color randomColor = lineColor;graphics.setColor(randomColor);graphics.drawLine(x1, x2, y1, y2);}}
}