feat: Add Druid monitoring controller for credential retrieval

ruoyi-admin/src/main/java/com/ruoyi/web/controller/monitor/DruidController.java

@@ -0,0 +1,54 @@
+package com.ruoyi.web.controller.monitor;
+
+import java.util.HashMap;
+import java.util.Map;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.http.CacheControl;
+import org.springframework.http.ResponseEntity;
+import org.springframework.security.access.prepost.PreAuthorize;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+import com.alibaba.druid.spring.boot.autoconfigure.properties.DruidStatProperties;
+import com.ruoyi.common.core.domain.AjaxResult;
+import com.ruoyi.common.utils.StringUtils;
+
+/**
+ * Druid 数据监控接口。
+ *
+ * @author Codex
+ */
+@RestController
+@RequestMapping("/monitor/druid")
+public class DruidController
+{
+    @Autowired
+    private DruidStatProperties druidStatProperties;
+
+    /**
+     * 获取当前环境的 Druid 登录信息，供已授权的管理前端自动登录使用。
+     *
+     * 注意：该接口返回敏感信息，只允许拥有数据监控权限的用户访问，并禁止缓存。
+     */
+    @PreAuthorize("@ss.hasPermi('monitor:druid:list')")
+    @GetMapping("/credentials")
+    public ResponseEntity<AjaxResult> getCredentials()
+    {
+        DruidStatProperties.StatViewServlet statViewServlet = druidStatProperties.getStatViewServlet();
+        if (statViewServlet == null || !statViewServlet.isEnabled()
+                || StringUtils.isEmpty(statViewServlet.getLoginUsername())
+                || StringUtils.isEmpty(statViewServlet.getLoginPassword()))
+        {
+            return ResponseEntity.ok()
+                    .cacheControl(CacheControl.noStore())
+                    .body(AjaxResult.error("Druid 监控登录配置未启用"));
+        }
+
+        Map<String, String> credentials = new HashMap<>(2);
+        credentials.put("username", statViewServlet.getLoginUsername());
+        credentials.put("password", statViewServlet.getLoginPassword());
+        return ResponseEntity.ok()
+                .cacheControl(CacheControl.noStore())
+                .body(AjaxResult.success(credentials));
+    }
+}