droptableframe.java

Java数据库编程实例（4）

package droptable;
import com.borland.jbcl.layout.*;
import java.awt.*;
import java.awt.event.*;
import java.sql.*;
import javax.swing.*;

/**
   * Title:				删除数据库中的表程序
   * Description:			教学示范
   * Copyright:				Copyright (c) 2003
   * Company:				北京师范大学计算机系
   * @author				孙一林
   * @version				1.0
   */

public class DropTableFrame extends JFrame {
  private JPanel contentPane;
  private XYLayout xYLayout1 = new XYLayout();       // 构造XYLayout布局管理器
  // 创建显示信息使用的组件
  private Label label1 = new Label();
  private TextField droptablenameField = new TextField();
  private Button droptableButton = new Button();

  Connection connection = null;                      // 声明Connection接口对象connection
  Statement statement = null;                        // 定义查询数据库的Statement对象

  public DropTableFrame() {
    enableEvents(AWTEvent.WINDOW_EVENT_MASK);
    try {
      jbInit();
    }
    catch(Exception e) {
      e.printStackTrace();
    }
  }

  private void jbInit() throws Exception  {
    contentPane = (JPanel) this.getContentPane();
    // 初始化组件
    label1.setText("删除表名称：");
    contentPane.setLayout(xYLayout1);
    this.setSize(new Dimension(400, 300));
    this.setTitle("删除数据库中的表");
    droptableButton.setLabel("删除表");
    droptableButton.addActionListener(new java.awt.event.ActionListener() { // droptableButton的事件监听方法
      public void actionPerformed(ActionEvent e) {
        droptableButton_actionPerformed(e);
      }
    });
    contentPane.add(label1, new XYConstraints(56, 73, 85, 33));
    contentPane.add(droptablenameField, new XYConstraints(164, 73, 108, 35));
    contentPane.add(droptableButton, new XYConstraints(164, 178, 102, 37));
  }

  protected void processWindowEvent(WindowEvent e) {
    super.processWindowEvent(e);
    if (e.getID() == WindowEvent.WINDOW_CLOSING) {
      System.exit(0);
    }
  }

  void droptableButton_actionPerformed(ActionEvent e) {// 处理droptableButton事件
    try {
      Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");  // 实例化JDBC-ODBC桥的驱动
      String url = "jdbc:odbc:TestDbStu";             // 设置连接字符串
      connection = DriverManager.getConnection(url);  // 连接数据库
      statement = connection.createStatement();
      String sql="drop table  "+droptablenameField.getText() ;
      statement.executeUpdate(sql);                   // 执行删除数据库中的表语句
      droptablenameField.setText("");
    }
    catch(SQLException ex){                           // 捕捉异常
      System.out.println("\nERROR:----- SQLException -----\n");
      while (ex != null) {
        System.out.println("Message:   " + ex.getMessage());
        System.out.println("SQLState:  " + ex.getSQLState());
        System.out.println("ErrorCode: " + ex.getErrorCode());
        ex = ex.getNextException();
      }
    }
    catch(Exception ex ) {
      ex.printStackTrace();
    }
    finally {
      try {
        if(statement != null) {
          statement.close();                                  // 关闭Statement接口实例
        }
        if(connection != null) {
          connection.close();                                 // 关闭Connection接口实例
        }
      }
      catch (SQLException ex)  {
        System.out.println("\nERROR:----- SQLException -----\n");
        System.out.println("Message:   " + ex.getMessage( ));
        System.out.println("SQLState:  " + ex.getSQLState());
        System.out.println("ErrorCode: " + ex.getErrorCode());
      }
    }
  }
}