Java后端实现生成验证码图片的示例代码

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Random;
 
/**
 * @author tobiasy
 * @date 2020/4/10
 */
public class ValidateCode {
 
    private int width = 160;
    private int height = 40;
    /**
     * 验证码字符个数
     */
    private int codeCount = 5;
    /**
     * 验证码干扰线数
     */
    private int lineCount = 150;
    /**
     * 验证码
     */
    private String code = null;
    /**
     * 验证码图片Buffer
     */
    private BufferedImage buffImg = null;
 
    // 验证码范围,去掉0(数字)和O(拼音)容易混淆的(小写的1和L也可以去掉,大写不用了)
//    private char[] codeSequence = {'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', '2', '3', '4', '5', '6', '7', '8', '9'};
    private char[] codeSequence = {'1', '2', '3', '4', '5', '6', '7', '8', '9'};
 
    public ValidateCode() {
        this.createCode();
    }
 
    public ValidateCode(int width, int height) {
        this.width = width;
        this.height = height;
        this.createCode();
    }
 
    public ValidateCode(int width, int height, int codeCount, int lineCount) {
        this.width = width;
        this.height = height;
        this.codeCount = codeCount;
        this.lineCount = lineCount;
        this.createCode();
    }
 
 
    public void createCode() {
        int x, fontHeight, codey;
        x = width / (codeCount + 2);
        fontHeight = height - 2;
        codey = height - 4;
        buffImg = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        Graphics2D g = buffImg.createGraphics();
        buffImg = g.getDeviceConfiguration().createCompatibleImage(width, height, Transparency.TRANSLUCENT);
        g.dispose();
        g = buffImg.createGraphics();
        g.fillRect(128, 128, width, height);
        Random random = new Random();
        Font font = new Font("微软雅黑", Font.PLAIN, fontHeight);
        g.setFont(font);
        for (int i = 0; i < lineCount; i++) {
            int xs = random.nextInt(width);
            int ys = random.nextInt(height);
            int xe = xs + random.nextInt(width / 8);
            int ye = ys + random.nextInt(height / 8);
            g.setColor(getRandomColor());
            g.drawLine(xs, ys, xe, ye);
        }
        StringBuilder randomCode = new StringBuilder();
        for (int i = 0; i < codeCount; i++) {
            String strRand = String.valueOf(codeSequence[random.nextInt(codeSequence.length)]);
            g.setColor(getRandomColor());
            g.drawString(strRand, (i + 1) * x, codey);
            randomCode.append(strRand);
        }
        code = randomCode.toString();
    }
 
    private Color getRandomColor(){
        Random random = new Random();
        return new Color(random.nextInt(255), random.nextInt(255), random.nextInt(255));
    }
 
 
    public void write(String path) throws IOException {
        OutputStream sos = new FileOutputStream(path);
        this.write(sos);
    }
 
 
    public void write(OutputStream sos) throws IOException {
        ImageIO.write(buffImg, "png", sos);
        sos.close();
    }
 
 
    public BufferedImage getBuffImg() {
        return buffImg;
    }
 
 
    public String getCode() {
        return code;
    }
 
    public static void main(String[] args) {
        ValidateCode vCode = new ValidateCode(160, 40, 4, 60);
        try {
            String path = "F:/test/images/" + System.currentTimeMillis() + ".png";
            FileOutputStream fileOutputStream = new FileOutputStream(new File(path));
            vCode.write(fileOutputStream);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}