fix: 启用验证码并生成图片

- captchaEnabled 改为 true
- 使用 Java AWT 生成验证码图片（4位随机字符）
- 登录时校验验证码并从内存 Map 移除
- 验证码图片为 PNG 格式 Base64 编码

pangu-admin/src/main/java/com/pangu/web/controller/LoginController.java

@@ -3,6 +3,10 @@ package com.pangu.web.controller;
 import com.pangu.common.core.domain.AjaxResult;
 import org.springframework.web.bind.annotation.*;
 
+import javax.imageio.ImageIO;
+import java.awt.*;
+import java.awt.image.BufferedImage;
+import java.io.ByteArrayOutputStream;
 import java.util.*;
 
 /**
@@ -16,13 +20,79 @@ public class LoginController {
      * 获取验证码
      */
     @GetMapping("/captchaImage")
-    public AjaxResult getCaptchaImage() {
+    public AjaxResult getCaptchaImage() throws Exception {
         AjaxResult result = AjaxResult.success();
-        // 开发阶段禁用验证码
-        result.put("captchaEnabled", false);
-        result.put("uuid", UUID.randomUUID().toString());
+        
+        String uuid = UUID.randomUUID().toString();
+        String code = generateRandomCode(4);
+        
+        // 生成验证码图片
+        String base64Img = generateCaptchaImage(code);
+        
+        result.put("captchaEnabled", true);
+        result.put("img", base64Img);
+        result.put("uuid", uuid);
+        
+        // 存储验证码到内存（实际应存 Redis，这里简化为静态 Map）
+        captchaStore.put(uuid, code.toLowerCase());
+        
         return result;
     }
+    
+    // 简易验证码存储（生产环境应使用 Redis）
+    private static final Map<String, String> captchaStore = new HashMap<>();
+    
+    /**
+     * 生成随机验证码
+     */
+    private String generateRandomCode(int length) {
+        String chars = "ABCDEFGHJKLMNPQRSTUVWXYZabcdefghjkmnpqrstuvwxyz23456789";
+        Random random = new Random();
+        StringBuilder code = new StringBuilder();
+        for (int i = 0; i < length; i++) {
+            code.append(chars.charAt(random.nextInt(chars.length())));
+        }
+        return code.toString();
+    }
+    
+    /**
+     * 生成验证码图片
+     */
+    private String generateCaptchaImage(String code) throws Exception {
+        int width = 100;
+        int height = 40;
+        
+        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
+        Graphics2D g = image.createGraphics();
+        
+        // 背景
+        g.setColor(Color.WHITE);
+        g.fillRect(0, 0, width, height);
+        
+        // 绘制字符
+        g.setFont(new Font("Arial", Font.BOLD, 25));
+        Random random = new Random();
+        Color[] colors = {Color.RED, Color.BLUE, Color.GREEN, Color.ORANGE, Color.MAGENTA};
+        
+        for (int i = 0; i < code.length(); i++) {
+            g.setColor(colors[random.nextInt(colors.length)]);
+            g.drawString(String.valueOf(code.charAt(i)), 15 + i * 20, 28);
+        }
+        
+        // 干扰线
+        for (int i = 0; i < 3; i++) {
+            g.setColor(colors[random.nextInt(colors.length)]);
+            g.drawLine(random.nextInt(width), random.nextInt(height), 
+                      random.nextInt(width), random.nextInt(height));
+        }
+        
+        g.dispose();
+        
+        // 转 Base64
+        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        ImageIO.write(image, "png", baos);
+        return Base64.getEncoder().encodeToString(baos.toByteArray());
+    }
 
     /**
      * 登录
@@ -31,6 +101,22 @@ public class LoginController {
     public AjaxResult login(@RequestBody Map<String, String> loginBody) {
         String username = loginBody.get("username");
         String password = loginBody.get("password");
+        String code = loginBody.get("code");
+        String uuid = loginBody.get("uuid");
+
+        // 验证码校验
+        if (code == null || uuid == null) {
+            return AjaxResult.error("验证码不能为空");
+        }
+        String storedCode = captchaStore.get(uuid);
+        if (storedCode == null) {
+            return AjaxResult.error("验证码已过期");
+        }
+        if (!storedCode.equals(code.toLowerCase())) {
+            return AjaxResult.error("验证码错误");
+        }
+        // 验证后移除
+        captchaStore.remove(uuid);
 
         // 开发阶段简单校验：admin/admin123
         if ("admin".equals(username) && "admin123".equals(password)) {