找不出毛病，求帮忙。Java，NetBeans，MySQL

Question

    private void insertActionPerformed(java.awt.event.ActionEvent evt) {                                      

        int result = queries.addStudent(stid.getText(), firstn.getText(), lastn.getText(), addrt.getText(), cit.getText(), provt.getText(), postct.getText());

        if (result == 1) {
            JOptionPane.showMessageDialog(this, "Person added!", "Person added", JOptionPane.PLAIN_MESSAGE);
        } else {
            JOptionPane.showMessageDialog(this, "Person not added!", "error", JOptionPane.PLAIN_MESSAGE);
        }

}

我自己测试了下，能打印出stid.getText()...他们的值，但是result里面取不到值，这是什么问题？addstudent方法是通过MySQL往数据库添加一个新列。

   

public int addStudent(String id, String fname, String lname, String addr, String ci, String prov, String postc) {
        int result = 0;
        try {
            insertNewStudent.setString(1, id);
            insertNewStudent.setString(2, fname);
            insertNewStudent.setString(3, lname);
            insertNewStudent.setString(4, addr);
            insertNewStudent.setString(5, ci);
            insertNewStudent.setString(6, prov);
            insertNewStudent.setString(7, postc);

            result = insertNewStudent.executeUpdate();
        } catch (SQLException sqlException) {
            sqlException.printStackTrace();
            close();
        }
        return result;
    }

错误提示：

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
 at demo.Register.insertActionPerformed(Register.java:142)
 at demo.Register.access$000(Register.java:14)
 at demo.Register$1.actionPerformed(Register.java:59)

                                

Answer 1

一楼说得对