怎么判断传输参数数组是否为null，为null程序是否正确

Question

方法：
public List> query(String sql, Object[] parameters)
throws Exception {

    List List = new ArrayList();

    Connection conn = DBUtil.getConnect();

    PreparedStatement pstmt = conn.prepareStatement(sql);

    for (int i = 0; i < parameters.length; i++) {
        // pstmt.setObject(第几个参数, 替换成什么)；
        pstmt.setObject(i + 1, parameters[i]);// 填充sql 语句
    }
    // 获取结果集
    ResultSet rs = pstmt.executeQuery();

    ResultSetMetaData md = rs.getMetaData();

    // 之后将获取的每一条记录封装到一个类中
    int columnCount = md.getColumnCount();

    //判断resultset是否为空
    if (rs.wasNull() == false) {

        System.out.println(rs.wasNull());

        while (rs.next()) {

            Map map = new HashMap();

            for (int i = 1; i <= columnCount; i++) {
                // rs.getObject(取第几个值)
                map.put(md.getColumnName(i), rs.getObject(i));
            }
            List.add(map);
        }
        rs.close();

        pstmt.close();

        conn.close();

        return List;

    } else {

        System.out.println("ResultSet为空");

        return null;
    }
}

测试：
sql = "select * from user_info where id > ? order by id asc";

    userList = databaseFactory.query(sql, new Object[]{2});

    if(userList != null) {

        for(Map<String, Object> user : userList) {

            System.out.println("username=" + user.get("username"));

            System.out.println("password=" + user.get("password"));

            System.out.println("inquiry2 ok");

            System.out.println("--------------------------------------");

Answer 1

if(parameters==null || parameters.length==0) return null;