验证码java_java实现验证码功能

实现验证码功能可以使用Java的AWT和BufferedImage类来生成图像验证码。以下是一个简单的实现示例：

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.util.Random;

public class CaptchaGenerator {
    private static final int WIDTH = 120; // 图片宽度
    private static final int HEIGHT = 40; // 图片高度
    private static final int CODE_LENGTH = 4; // 验证码长度
    private static final String CODES = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"; // 验证码字符集
    private static final Random random = new Random();

    public static BufferedImage generate() {
        // 创建图像对象
        BufferedImage image = new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);
        Graphics g = image.getGraphics();
        // 填充背景色
        g.setColor(Color.WHITE);
        g.fillRect(0, 0, WIDTH, HEIGHT);
        // 生成随机验证码
        StringBuilder code = new StringBuilder();
        for (int i = 0; i < CODE_LENGTH; i++) {
            char c = CODES.charAt(random.nextInt(CODES.length()));
            code.append(c);
        }
        // 绘制验证码
        g.setColor(Color.BLACK);
        g.setFont(new Font("Arial", Font.BOLD, 20));
        for (int i = 0; i < CODE_LENGTH; i++) {
            char c = code.charAt(i);
            g.drawString(String.valueOf(c), 20 + i * 25, 25);
        }
        // 添加干扰线
        g.setColor(Color.GRAY);
        for (int i = 0; i < 5; i++) {
            int x1 = random.nextInt(WIDTH);
            int y1 = random.nextInt(HEIGHT);
            int x2 = random.nextInt(WIDTH);
            int y2 = random.nextInt(HEIGHT);
            g.drawLine(x1, y1, x2, y2);
        }
        // 释放资源
        g.dispose();
        return image;
    }
}

调用`generate()`方法即可生成一个包含随机验证码的BufferedImage对象。可以将该对象输出到HTTP响应中，以便客户端进行验证。