我想將db連接與其他類分開,因此我不需要再爲每個要創建的類編寫db連接。我希望登錄類能夠訪問不同類的數據庫連接
這是數據庫連接類
package bloodbank;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
public class dbconnection {
PreparedStatement pst = null;
ResultSet rs = null;
public dbconnection() {}
public void connect() {
try {
Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
Connection con =
DriverManager.getConnection("jdbc:sqlserver://localhost:1433;
databaseName=BloodManagementSystem;user=yusuf;password=ali1234");
} catch (ClassNotFoundException | SQLException e) {
}
}
public PreparedStatement prepareStatement(String select__from_Users_where_Username_and_Pas) {
throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
}
}
這是登錄類登錄按鈕
import bloodbank.dbconnection;
import java.awt.HeadlessException;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import javax.swing.JOptionPane;
public class login extends javax.swing.JFrame {
public login() {
initComponents();
}
@SuppressWarnings("unchecked")
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_jButton1ActionPerformed
try
{
dbconnection con = new dbconnection();
con.connect();
PreparedStatement pst = con.prepareStatement("Select * from Users where Username=? and Password=?");
pst.setString(1, jTextField1.getText());
pst.setString(2, jTextField2.getText());
ResultSet rs = pst.executeQuery();
if(rs.next()) {
JOptionPane.showMessageDialog(null, "Username and Password correct");
Mainform field = new Mainform();
field.setVisible(true);
setVisible(false);
} else {
JOptionPane.showMessageDialog(null, "invalid username and password");
}
}
catch(SQLException | HeadlessException e){
JOptionPane.showMessageDialog(null, e);
}
}
public static void main(String args[]) {
java.awt.EventQueue.invokeLater(() -> {
new login().setVisible(true);
});
}
}
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是的,這是一個好主意。問題是什麼? – MadProgrammer
我想有人來測試這個代碼,因爲當我運行它時,它顯示了很多像這樣的錯誤 –