有没有帮我解释一下各各代码

import java.awt.event.ActionEvent;

/**

登录窗口
@author wen
/
public class LoginView extends JFrame{
//private JFrame frame;
/**
- 用户名
- /
  private JTextField textField;
  /**
- 密码
- /
  private JPasswordField passwordField;
/**
- Launch the application.
- /
  public static void main(String[] args) {
  EventQueue.invokeLater(new Runnable() {
```
  public void run() {
      try {
          LoginView window = new LoginView();
          window.setVisible(true);
      } catch (Exception e) {
          e.printStackTrace();
      }
  }
```
  });
  }
/**
- Create the application.
- /
  public LoginView() {
  initialize();
  }
/**
- Initialize the contents of the frame.
- /
  private void initialize() {
  //this = new JFrame();
  this.setTitle("车辆管理系统 - 管理员登录");
  this.setBounds(100, 100, 450, 300);
  this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  this.getContentPane().setLayout(null); JPanel panel = new JPanel();
  panel.setBounds(0, 0, 434, 261);
  this.getContentPane().add(panel);
  panel.setLayout(null); JLabel lblNewLabel = new JLabel("登录名：");
  lblNewLabel.setBounds(87, 73, 60, 30);
  lblNewLabel.setFont(new Font("宋体", Font.PLAIN, 14));
  panel.add(lblNewLabel);
  lblNewLabel.setHorizontalAlignment(SwingConstants.CENTER); JLabel lblNewLabel_1 = new JLabel("密码：");
  lblNewLabel_1.setBounds(99, 122, 44, 30);
  lblNewLabel_1.setHorizontalAlignment(SwingConstants.CENTER);
  lblNewLabel_1.setFont(new Font("宋体", Font.PLAIN, 14));
  panel.add(lblNewLabel_1); textField = new JTextField();
  textField.setBounds(147, 67, 194, 30);
  panel.add(textField);
  textField.setColumns(10); passwordField = new JPasswordField();
  passwordField.setBounds(147, 123, 194, 30);
  panel.add(passwordField); JButton btnNewButton = new JButton("登录");
  btnNewButton.setBounds(180, 186, 93, 30); btnNewButton.addActionListener(new ActionListener() {
```
  public void actionPerformed(ActionEvent e) {
      System.out.println("用户名："+textField.getText()+",密码："+passwordField.getText());
      String userName = textField.getText().trim();
      String password = new String(passwordField.getPassword()).trim();
      if (userName == null || "".equals(userName)) {
          JOptionPane.showMessageDialog(null, "登录名不能为空");
          return;
      }
      if (password == null || "".equals(password)) {
          JOptionPane.showMessageDialog(null, "密码不能为空");
          return;
      }
      try {
            if (Database.userLogin(userName, password)) {
                dispose();
                MainView mv = new MainView();
                //mv.setVisible(true);
            } else {
                  JOptionPane.showMessageDialog(null, "登录失败，请核对登录信息");
                  return;
            }
      } catch(Exception ex) {
          ex.printStackTrace();
          JOptionPane.showMessageDialog(null, "登录失败");
          return;
      }
  }
```
  });
  panel.add(btnNewButton);
  }
  }

就是swing窗体的车辆管理系统登陆操作。根据用户输入的用户名和密码进行空判断，不为空的时候，再去数据库查询，当前用户是否存在，如果用户名或密码错误，则提示登录失败。