java - 在 Oracle DB 中插入字符串值在 sql Developer 中显示空值

Question

我正在使用jsp在oracle tabales中插入一些值，插入时它不会给出任何错误/异常，但是当我使用sqldeveloper检查oracle 11g中的记录时，它在所有字段中显示null(它确实插入了一 strip 有null的记录)值)

这里是我的jsp doPost方法代码

    protected void doPost(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {

    String username = String.valueOf(request.getAttribute("username"));
    String password = String.valueOf(request.getAttribute("password"));
    try {
        PreparedStatement preparedStatement = con.prepareStatement("insert into libraryadmin values (?, ?)");
        preparedStatement.setString(1, username);
        preparedStatement.setString(2, password);
        int result = preparedStatement.executeUpdate();
        PrintWriter out = response.getWriter();

        if (result == 1) {
            out.print("<h1>USER CREATED</h1>");
        } else {
            out.print("<h1>ERROR</h1>");
        }

    } catch (SQLException e) {
        e.printStackTrace();
    }

}

sqldeveloper 的输出

PS:我使用的是oracle的系统用户

Answer 1

而不是

String username = String.valueOf(request.getAttribute("username"));
String password = String.valueOf(request.getAttribute("password"));

使用

String username = String.valueOf(request.getParameter("username"));
String password = String.valueOf(request.getParameter("password"));