删除无用代码

src/util/DatabaseUtil.java

@@ -29,18 +29,4 @@ public class DatabaseUtil {
     public static Connection getConnection() throws SQLException {
         return DriverManager.getConnection(URL, USERNAME, PASSWORD);
     }
-
-    /**
-     * 关闭数据库连接
-     * @param conn 要关闭的连接对象
-     */
-    public static void closeConnection(Connection conn) {
-        if (conn != null) {
-            try {
-                conn.close();
-            } catch (SQLException e) {
-                e.printStackTrace();
-            }
-        }
-    }
 }