querypanel.java

用JAVA开发的~使用RMI进行异地访问的简单实例程序

// 查询通话记录的图形用户界面
package Telephone;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;


public class QueryPanel extends JPanel implements ActionListener {
    // 属性
    protected JApplet applet;					// 当前正在运行的Applet
    protected JTextField subscriberTextField;	// 输入用户名字的字段
    protected JPanel tablePanel;				// 显示二维表的面板

    // 构造方法，显示图形用户界面
    public QueryPanel(JApplet applet) {
        this.applet = applet;
        setLayout(new BorderLayout());
        setBorder(BorderFactory.createEmptyBorder(12, 12, 12, 12));
        // 查询条件面板
        JPanel conditionPanel = new JPanel(new BorderLayout());
        conditionPanel.setBorder(BorderFactory.createEtchedBorder());
        add("North", conditionPanel);
          // 顾客姓名面板
          JPanel subscriberPanel = new JPanel(new FlowLayout(FlowLayout.LEFT));
          conditionPanel.add("Center", subscriberPanel);
            // 顾客姓名的标签
            JLabel subscriberLabel = new JLabel("电话用户名");
            subscriberPanel.add(subscriberLabel);
            // 顾客姓名的文本域
            subscriberTextField = new JTextField();
            subscriberTextField.setPreferredSize(new Dimension(160, 18));
            subscriberPanel.add(subscriberTextField);
          // 按钮面板
          JPanel buttonPanel = new JPanel(new FlowLayout(FlowLayout.RIGHT));
          conditionPanel.add("East", buttonPanel);
            // 查询按钮
            JButton queryButton = new JButton("查询");
            queryButton.setActionCommand("QUERY");
            queryButton.addActionListener(this);
            buttonPanel.add(queryButton);
            // 重置按钮
            JButton resetButton = new JButton("清除");
            resetButton.setActionCommand("RESET");
            resetButton.addActionListener(this);
            buttonPanel.add(resetButton);
        // 以带标签窗格显示查询结果
        JTabbedPane resultTabbedPane = new JTabbedPane();
        add(resultTabbedPane);
          // 查询页面
          tablePanel = new JPanel(new BorderLayout());
          resultTabbedPane.addTab("查询结果", null, tablePanel, "");
        // 显示上述GUI控件
        validate();
        setVisible(true);
    }
    // 实现ActionListener规定的事件处理程序，对发生的事件evt进行处理
    public void actionPerformed(ActionEvent evt) {
        String cmd = evt.getActionCommand();
        if (cmd.equals("QUERY")) {    // 处理"查询"按钮
            String subscriber = subscriberTextField.getText();
            if (subscriber.equals(""))  return;
            // 调用远程对象的方法进行查询
            Database.DatabaseTableModel result = null;
            try {
                // 从Applet提取主机名
                String host = "//" + applet.getCodeBase().getHost() + "/";
                // 远程对象的标识必须与服务程序注册时使用的对象标识完全相同
                String objectId = "CallManager";
                // 根据主机名与对象标识解析远程对象
                CallManagerInterface manager = (CallManagerInterface) 
                    java.rmi.Naming.lookup(host + objectId);
                // 调用远程对象方法查询用户的通话记录
                result = manager.getCallHistory(subscriber);
            } catch(Exception exc) {
                exc.printStackTrace();
            }
            // 将查询结果显示为二维表
            tablePanel.removeAll();
            tablePanel.add(new JScrollPane(new JTable(result)));
            tablePanel.validate();
        } else if (cmd.equals("RESET")) {    // 处理"清除"按钮
            subscriberTextField.setText("");
            subscriberTextField.requestFocus();
        }
    }
}