Question

java新手，求指点

以下为代码：import javax.swing.*;import java.awt.*;import java.awt.event.*;import java.sql.*;public class UserLogin extends JFrame implements ActionListener{ JPanel panel1=new JPanel(); JLabel label1=new JLabel("请输入用户名："); JLabel label2=new JLabel("请输入密码："); JLabel label3=new JLabel(); JTextField userName=new JTextField(""); JPasswordField passWord=new JPasswordField(""); JButton button1=new JButton("登陆"); JButton button2=new JButton("退出"); public UserLogin(){ super("用户身份验证"); button1.addActionListener(this); button2.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e1) { dispose(); //释放此窗口及其组件所有的本机屏幕资源（内存） } }); this.addWindowListener(new WindowAdapter(){ public void windowClosing(WindowEvent e2){ System.exit(0); } }); this.getContentPane().setLayout(new FlowLayout(FlowLayout.CENTER)); panel1.setLayout(new GridLayout(5, 1,4,4)); this.getContentPane().add(panel1); panel1.add(label1); panel1.add(userName); panel1.add(label2); panel1.add(passWord); panel1.add(button1); panel1.add(button2); setSize(300,150); setVisible(true); } public void actionPerformed(ActionEvent e3){ try{ Class.forName("oracle.jdbc.driver.OracleDriver"); String url="jdbc:oracle:thin:@localhost:1521:ORCL"; Connection conn=DriverManager.getConnection(url,"studenteg","这里是密码"); String sql="select * from all_users where username='?'"; PreparedStatement stmt=conn.prepareStatement(sql); stmt.setString(1,userName.getText()); //stmt.setString(2,passWord.getText()); //别说密码了 用户名都不行 ResultSet rs=stmt.executeQuery(); if(rs.next()){ label3.setText("欢迎您登陆本系统"); }else{ label3.setText("非法用户"); } }catch(Exception e){ e.printStackTrace(); } } public static void main(String[] args) { new UserLogin(); }}一直报错，求告知哪里有问题，拜托了
我还是传图吧 这是关键的部分

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Answer 1

错误很明显是数据库连接不上，用工具连接下你得数据库测试下用户名密码是否正确、数据库服务是否启动等。