:art:修改系统配置表数据结构，添加数据库连接检测

src/main/java/cn/hellohao/dao/ConfdataMapper.java

@@ -0,0 +1,11 @@
+package cn.hellohao.dao;
+
+import cn.hellohao.pojo.Confdata;
+import org.apache.ibatis.annotations.Mapper;
+import org.apache.ibatis.annotations.Param;
+
+@Mapper
+public interface ConfdataMapper {
+    Confdata selectConfdata(@Param("key") String key);
+    Integer updateConfdata(Confdata confdata);
+}