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了困难。我正在尝试从用户名和密码jTextFields中检索文本，然后将它们查询到数据库，但它无法正常工作。目前我正在

java.lang.ArrayIndexOutOfBoundsException: 0

我很遗憾不知道为什么。任何帮助都会非常感激。

Answer 1

您的查询和背后的逻辑需要做很多工作：

首先，如果你想要一个参数化的查询，你必须使用'？'而不是价值。然后pst.setString就可以了。

其次，您必须影响pst.executeQuery();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);
}

在Java中使用SQLite实现登录系统很困难

1 个答案: