java - 在Java中使用SQLite实现登录系统有很大困难

Question

private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         
    String query;
    boolean login = false;
    String username = jTextField1.getText();
    String password = jTextField2.getText();
    try{
    query = "SELECT (cUsername AND cPassword) FROM Customer WHERE cUsername = '"+username+"' AND cPassword = '"+password+"'";
    pst = conn.prepareStatement(query);
    pst.setString(1, username);
    pst.setString(2, password);
    pst.executeQuery();

    String userCheck = rs.getString(1);
    String passCheck = rs.getString(2);

    if((userCheck.equals(username)) && (passCheck.equals(password)))
    {
        login = true;
        System.out.println("It actually works?!");
    }
    else
    {
        login = false;
        System.out.println("Psyche, that's the wrong number!");
    }

    }
    catch(Exception e){
        System.out.println(e);
    }

    System.exit(0);

}                                        

我目前在代码中实现登录系统时遇到困难。我试图从用户名和密码 jTextFields 检索文本，然后将它们查询到数据库，但它不起作用。目前我正在

java.lang.ArrayIndexOutOfBoundsException: 0

不幸的是我不知道为什么。任何帮助将不胜感激。

Answer 1

您的查询和背后的逻辑还有很多工作要做:

首先，如果你想要参数化查询，你必须使用'?'而不是值。然后 pst.setString 就可以工作了。

其次，您必须将 pst.executeQuery(); 影响到 ResultSet

query = "SELECT cUsername, cPassword FROM Customer WHERE cUsername = ? AND cPassword = ?";
pst = conn.prepareStatement(query);
pst.setString(1, username);
pst.setString(2, password);
ResultSet rs = pst.executeQuery();

if (rs.next()) {   
   String userCheck = rs.getString(1);
   String passCheck = rs.getString(2);
}