java编写Dialog类包含的内容可以包括：图标、标题、提示内容、确认按钮、取消按钮，关闭按钮等6个内容组成。并画出类图

以下是Java编写Dialog类的代码和类图：

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

public class Dialog extends JDialog {
    private JLabel iconLabel;
    private JLabel titleLabel;
    private JLabel messageLabel;
    private JButton okButton;
    private JButton cancelButton;
    private JButton closeButton;

    public Dialog(JFrame parent, String title, String message, String iconPath) {
        super(parent, title, true);
        
        // 设置对话框大小
        setSize(400, 200);
        
        // 设置对话框位置
        setLocationRelativeTo(parent);
        
        // 设置对话框布局
        setLayout(new BorderLayout());
        
        // 设置图标
        ImageIcon icon = new ImageIcon(iconPath);
        iconLabel = new JLabel(icon);
        add(iconLabel, BorderLayout.WEST);
        
        // 设置标题
        titleLabel = new JLabel(title);
        titleLabel.setFont(new Font("宋体", Font.BOLD, 16));
        JPanel titlePanel = new JPanel();
        titlePanel.add(titleLabel);
        add(titlePanel, BorderLayout.NORTH);
        
        // 设置提示内容
        messageLabel = new JLabel(message);
        JPanel messagePanel = new JPanel();
        messagePanel.add(messageLabel);
        add(messagePanel, BorderLayout.CENTER);
        
        // 设置确认按钮
        okButton = new JButton("确定");
        okButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                setVisible(false);
            }
        });
        
        // 设置取消按钮
        cancelButton = new JButton("取消");
        cancelButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                setVisible(false);
            }
        });
        
        // 设置关闭按钮
        closeButton = new JButton("关闭");
        closeButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                setVisible(false);
            }
        });
        
        // 设置按钮面板
        JPanel buttonPanel = new JPanel();
        buttonPanel.setLayout(new FlowLayout(FlowLayout.RIGHT));
        if (parent != null) {
            buttonPanel.add(cancelButton);
        }
        buttonPanel.add(okButton);
        buttonPanel.add(closeButton);
        add(buttonPanel, BorderLayout.SOUTH);
    }
}

类图如下：

+-------------------+
|       Dialog      |
+-------------------+
| - iconLabel: JLabel|
| - titleLabel: JLabel|
| - messageLabel: JLabel|
| - okButton: JButton|
| - cancelButton: JButton|
| - closeButton: JButton|
+-------------------+
| + Dialog(JFrame, String, String, String)|
+-------------------+

其中，`JLabel`、`JButton`、`JPanel`、`Font`、`ImageIcon`、`ActionEvent`、`ActionListener`、`BorderLayout`和`FlowLayout`都是Java Swing中的类。