小说网站|基于Springboot+Vue实现在线小说阅读网站（二）

package com.spring.controller;
import com.spring.util.DESUtil;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpSession;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
/**
 * 验证码控制器
 */
@Controller
public class CaptchaController extends BaseController {
    /**
     * 输出验证码图片,并记录session “random” 里等待登录时写入
     */
    @RequestMapping("/captcha")
    public String Index() {
        // 把验证码字符串写入session 中，保存待下次验证时使用
        String sRand = createRandomString(4);
        try {
            // 输出渲染好的内容到前端浏览器
            if (isAjax()) {
                String result = null;
                do {
                    try {
                        result = DESUtil.encrypt("CaptchControllerPassword", sRand);
                    } catch (Exception e) {
                        result = null;
                    }
                    if (result != null) {
                        if (!sRand.equals(DESUtil.decrypt("CaptchControllerPassword", result))) {
                            result = null; // 解不出来所以出错
                        }
                    }
                } while (result == null);
                assign("url", "/randtocaptch?captchToken=" + urlencode(result));
                assign("token", result);
                return json();
            } else {
                //byte[] img = xxx;
                response.setContentType("image/jpeg"); // 定义输出类型为 图片
                response.setHeader("Pragma", "No-cache"); // 设置为无缓存
                response.setHeader("Cache-Control", "no-cache"); // 设置为无缓存
                response.setDateHeader("Expires", 0); // 设置缓存时间为0秒后过期
                request.getSession().setAttribute("random", sRand);
                ServletOutputStream stream = response.getOutputStream();
                createCaptch(sRand, stream);
                stream.flush();
                stream.close();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return "success";
    }
    /**
     * url 编码，中文要进行编码输出
     * @param str
     * @return
     */
    public static String urlencode(Object str) {
        try {
            return java.net.URLEncoder.encode(String.valueOf(str), "UTF-8");
        } catch (Exception e) {
            e.printStackTrace();
        }
        return str.toString();
    }
    /**
     * 使用上面的加密字符串生成验证码
     * @return
     */
    @RequestMapping("/randtocaptch")
    public String getCaptch() throws IOException {
        String captchToken = request.getParameter("captchToken");
        String sRand = DESUtil.decrypt("CaptchControllerPassword", captchToken);
        HttpSession session = request.getSession();
        {
            //byte[] img = xxx;
            response.setContentType("image/jpeg"); // 定义输出类型为 图片
            response.setHeader("Pragma", "No-cache"); // 设置为无缓存
            response.setHeader("Cache-Control", "no-cache"); // 设置为无缓存
            response.setDateHeader("Expires", 0); // 设置缓存时间为0秒后过期
            ServletOutputStream stream = response.getOutputStream();
            createCaptch(sRand, stream);
            stream.flush();
            stream.close();
        }
        return "success";
    }
    private String createRandomString(int len) {
        // 生成随机数类
        Random random = new Random();
        String result = "";
        for (int i = 0; i < len; i++) {
            String rand = String.valueOf(random.nextInt(10));
            result += rand;
        }
        return result;
    }
    private void createCaptch(String randomstr, OutputStream stream) {
        int width = 60, height = 20; // 定义图片宽为 60  高度为 20
        // 创建图片缓冲区
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        // 获取渲染画板
        Graphics g = image.getGraphics();
        // 生成随机数类
        Random random = new Random();
        // 设置颜色
        g.setColor(getRandColor(200, 250));
        // 绘制矩形
        g.fillRect(0, 0, width, height);
        // 设置字体信息
        g.setFont(new Font("Times New Roman", Font.PLAIN, 18));
        // 设置颜色信息
        g.setColor(getRandColor(160, 200));
        // 写入干扰线
        for (int i = 0; i < 155; i++) {
            int x = random.nextInt(width);
            int y = random.nextInt(height);
            int xl = random.nextInt(12);
            int yl = random.nextInt(12);
            g.drawLine(x, y, x + xl, y + yl);
        }
        // 写入验证码字符串
        for (int i = 0; i < randomstr.length(); i++) {
            String rand = randomstr.substring(i, i + 1); //String.valueOf(random.nextInt(10));
            g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110)));
            g.drawString(rand, 13 * i + 6, 16);
        }
        g.dispose(); // 释放画板
        try {
            // 输出渲染好的内容到前端浏览器
            ImageIO.write(image, "JPEG", stream);
            stream.flush();
            stream.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    /**
     * 获取随机颜色
     * @param fc
     * @param bc
     * @return
     */
    protected Color getRandColor(int fc, int bc) {
        Random random = new Random();
        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);
    }
}