java - 准备语句错误: Parameter 12 undefined

Question

我有十一个字段想要插入到数据库中。显示的错误是我的 12 参数未定义，即 ps.executeUpdate()。我应该怎么办？

我的插入方法如下。

public void update(User user){
        try{
        Connection conn = DbUtils.getConnection();
        PreparedStatement ps = conn.prepareStatement("UPDATE db.db set id = ?,username = ?,password = ?,firstname = ?, lastname = ?, fathersname =?, gender = ?, email = ?,address =? , phnno = ?, courses = ?" + "WHERE id =?");
        ps.setInt(1, user.getId());
        ps.setString(2, user.getName());
        ps.setString(3, user.getPwd());
        ps.setString(4, user.getFname());
        ps.setString(5,  user.getLname());
        ps.setString(6, user.getFathername());
        ps.setString(7, user.getAddress());
        ps.setString(8, user.getEmail());
        ps.setString(9, user.getGender());
        ps.setString(10, user.getPhno());
        ps.setString(11, user.getCradio());
        ps.execute();           
        }catch(Exception e){
            e.printStackTrace();            
    }
    `

Answer 1

函数应该有另一个参数，用于 12 个占位符。 像这样:

public void update(User user){
        try{
        Connection conn = DbUtils.getConnection();
        PreparedStatement ps = conn.prepareStatement("UPDATE db.db set id = ?,username = ?,password = ?,firstname = ?, lastname = ?, fathersname =?, gender = ?, email = ?,address =? , phnno = ?, courses = ?" + " WHERE id =?");
        ps.setInt(1, user.getId());
        ps.setString(2, user.getName());
        ps.setString(3, user.getPwd());
        ps.setString(4, user.getFname());
        ps.setString(5,  user.getLname());
        ps.setString(6, user.getFathername());
        ps.setString(7, user.getAddress());
        ps.setString(8, user.getEmail());
        ps.setString(9, user.getGender());
        ps.setString(10, user.getPhno());
        ps.setString(11, user.getCradio());
        ps.setInt(12, user.getId()); //parameter 12 added
        ps.execute();           
        }catch(Exception e){
            e.printStackTrace();            
    }

您真的想也更新 ID 字段吗？