[feat][M]:新增查找用户名和密码的持久层操作函数

java/src/main/java/com/hzu/bookingsystem/repository/UserRepository.java

@@ -8,4 +8,6 @@ public interface UserRepository extends JpaRepository<User,String> {
     User findByUId(Integer uId);
 
     void deleteByUId(Integer uId);
+
+    User findByUsernameAndPassword(String username,String password);
 }