Question

我想用数据库列（SQLite）填充JComboBox。

我的数据库连接是通过anther包中名为DatabaseConnection setup的类设置的。

以下是它的样子

import java.sql.*;

import javax.swing.JOptionPane;

public class DatabaseConnection {
Connection conn = null;

public static Connection ConnectDB() {

    try {
        Class.forName("org.sqlite.JDBC");
        Connection conn = DriverManager.getConnection("jdbc:sqlite:database.db");
        JOptionPane.showMessageDialog(null, "Connection Established");
        conn.setAutoCommit(false);
        return conn;
    } catch (Exception e) {
        JOptionPane.showMessageDialog(null, e);
        return null;
    }
}
}

在我的JFrame类中，我正在创建以下方法，根据youtube教程应该可以使用

public void PopulateJCB()
{
    String queryString = "SELECT DISTINCT [Account Name] FROM main ORDER BY [Account Name]";
    try
    {
        Connection statJCBaccountname = DatabaseConnection.ConnectDB();
        Statement stmt = statJCBaccountname.createStatement();
        ResultSet rsJCBaccountname = stmt.executeQuery(queryString);

        while (rsJCBaccountname.next())
        {
            comboAccountName.addItem(rsJCBaccountname.getString(1));
        }

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

}

但它在“comboAccountName.addItem（rsJCBaccountname.getString（1））”中显示以下错误;“

Multiple markers at this line
- Type safety: The method addItem(Object) belongs to the raw type JComboBox. References to generic type JComboBox<E> should be 
 parameterized
- comboAccountName cannot be resolved

请帮忙！

Answer 1

我不确定你在期待什么...

statJCBaccountname甚至不在您提供的代码示例中，但编译器说该变量未定义
createStatement类

DatabaseConnection

您需要在程序编译之前解决这些问题。除非你了解作者，否则我建议远离YouTube教程。

请查看JDBC Database Access了解更多详情......

Java - 使用SQLite数据库填充JCombobox

1 个答案: