Question

我正在尝试创建一个程序来访问MS Access中的数据库，我认为它没有正确访问它，但我也遇到了applet工作的问题。当我运行该程序时，小程序出现，但它没有任何内容。我已创建Access数据库，保存它，并通过控制面板中的ODBC添加它。这是我的代码：

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.sql.ResultSet;

public class GUI extends Database{
private JFrame JF;
private JLabel JLFName;
private JLabel JLLName;
private JLabel JLAge;
private JTextField JTFName;
private JTextField JTLName;
private JTextField JTAge;
private JButton NxtBtn = new JButton("Next");
private JButton PrvBtn = new JButton("Previous");
private JButton FstBtn = new JButton("First");
private JButton LstBtn = new JButton("Last");
private JButton UpdBtn = new JButton("Update");
private JButton DelBtn = new JButton("Delete");
private JButton AddBtn = new JButton("Add");
private JButton SveBtn = new JButton("Save");
public GUI(){
    Frame();
    BtnAction();
}
public void Frame(){
    JF = new JFrame();
    JF.setVisible(true);
    JF.setSize(600, 400);
    JF.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    JLFName = new JLabel("First Name");
    JLLName = new JLabel("Last Name");
    JLAge = new JLabel("Age Name");
    JTFName = new JTextField(10);
    JTLName = new JTextField(10);
    JTAge = new JTextField(10);
    JPanel JP = new JPanel();
    JP.add(JLFName);
    JP.add(JTFName);
    JP.add(JLLName);
    JP.add(JTLName);
    JP.add(JLAge);
    JP.add(JTAge);
    JP.add(NxtBtn);
    JP.add(PrvBtn);
    JP.add(FstBtn);
    JP.add(LstBtn);
    JP.add(UpdBtn);
    JP.add(DelBtn);
    JP.add(AddBtn);
    JP.add(SveBtn);
    JF.add(JP);
    try{
        RS.next();
        JTFName.setText(RS.getString("FName"));
        JTLName.setText(RS.getString("LName"));
        JTAge.setText(RS.getString("Age"));
    }
    catch(Exception ex){
    }
}
public void BtnAction(){
    NxtBtn.addActionListener(new ActionListener(){
        public void actionPerformed(ActionEvent e){
            try{
                if(RS.next()){
                    JTFName.setText(RS.getString("FName"));
                    JTLName.setText(RS.getString("LName"));
                    JTAge.setText(RS.getString("Age"));
                }
                else{
                    RS.previous();
                    JOptionPane.showMessageDialog
                    (null, "No more records");
                }
            }
            catch(Exception ex){    
            }
        }
    });
    PrvBtn.addActionListener(new ActionListener(){
        public void actionPerformed(ActionEvent e){
            try{
                if(RS.previous()){
                    JTFName.setText(RS.getString("FName"));
                    JTLName.setText(RS.getString("LName"));
                    JTAge.setText(RS.getString("Age"));
                }
                else{
                    RS.next();
                    JOptionPane.showMessageDialog
                    (null, "No more records");
                }
            }
            catch(Exception ex){    
            }
        }
    });
    LstBtn.addActionListener(new ActionListener(){
        public void actionPerformed(ActionEvent e){
            try{
                RS.last();
                JTFName.setText(RS.getString("FName"));
                JTLName.setText(RS.getString("LName"));
                JTAge.setText(RS.getString("Age"));
            }
            catch(Exception ex){    
            }
        }
    });
    FstBtn.addActionListener(new ActionListener(){
        public void actionPerformed(ActionEvent e){
            try{
                RS.first();
                JTFName.setText(RS.getString("FName"));
                JTLName.setText(RS.getString("LName"));
                JTAge.setText(RS.getString("Age"));
            }
            catch(Exception ex){    
            }
        }
    });
    UpdBtn.addActionListener(new ActionListener(){
        public void actionPerformed(ActionEvent e){
            String FName = JTFName.getText();
            String LName = JTLName.getText();
            String Age = JTAge.getText();
            try{
                RS.updateString("FName", FName);
                RS.updateString("LName", LName);
                RS.updateString("Age", Age);
                RS.updateRow();
                JOptionPane.showMessageDialog
                (null, "Record Updated");
            }
            catch(Exception ex){    
            }
        }
    });
    DelBtn.addActionListener(new ActionListener(){
        public void actionPerformed(ActionEvent e){
            try{
                RS.deleteRow();
                St.close();
                RS.close();
                St = Con.createStatement(
                    ResultSet.TYPE_SCROLL_INSENSITIVE, 
                    ResultSet.CONCUR_UPDATABLE);
                String sql = "select * from MyTable";
                RS = St.executeQuery(sql);
                RS.next();
                JTFName.setText(RS.getString("FName"));
                JTLName.setText(RS.getString("LName"));
                JTAge.setText(RS.getString("Age"));
            }
            catch(Exception ex){    
            }
        }
    });
    AddBtn.addActionListener(new ActionListener(){
        public void actionPerformed(ActionEvent e){
            JTFName.setText(" ");
            JTLName.setText(" ");
            JTAge.setText(" ");
        }
    });
    SveBtn.addActionListener(new ActionListener(){
        public void actionPerformed(ActionEvent e){
            String FName = JTFName.getText();
            String LName = JTLName.getText();
            String Age = JTAge.getText();
            try{
                RS.moveToInsertRow();
                RS.updateString("FName", FName);
                RS.updateString("LName", LName);
                RS.updateString("Age", Age);
                RS.insertRow();
                St.close();
                RS.close();
                St = Con.createStatement(
                    ResultSet.TYPE_SCROLL_INSENSITIVE, 
                    ResultSet.CONCUR_UPDATABLE);
                String sql = "select * from MyTable";
                RS = St.executeQuery(sql);
                RS.next();
                JTFName.setText(RS.getString("FName"));
                JTLName.setText(RS.getString("LName"));
                JTAge.setText(RS.getString("Age"));
            }
            catch(Exception ex){        
            }
        }
    });     
}
}




import java.sql.*;
public class Database{
Connection Con;
Statement St;
ResultSet RS;
public Database(){
    Connect();
}
public void Connect(){
    try{
        String driver = "sun.jdbc.odbc.JdbcOdbcDriver";
        Class.forName(driver);
        String Database = "jdbc:odbc:FinalDB";
        Con = DriverManager.getConnection(Database);
        St = Con.createStatement(
                ResultSet.TYPE_SCROLL_INSENSITIVE, 
                ResultSet.CONCUR_UPDATABLE);
        String sql = "select * from MyTable";
        RS = St.executeQuery(sql);
    }
    catch(Exception ex){    
    }
}
public static void main(String[] args){
    new Database();
    new GUI();
}
}

Answer 1

你必须写JF.setVisible（true）;初始化所有组件并将其添加到框架后的指令。那种方法吸引了他们。

Java，gui不工作/没有出现在applet中。数据库未被访问

1 个答案: