bookdelete.java

采用java+sql实现图书管理系统

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

public class BookDelete
    extends JFrame
    implements ActionListener {
  DataBaseManager db = new DataBaseManager();
  ResultSet rs;//返回查询的结果集
  Container c;//Container继承于Componet
  JLabel TipLabel = new JLabel("请输入要删除的书名：", JLabel.CENTER);//显示标签
  JTextField bookDeleteTextField = new JTextField(15);//创建可以编辑的删除文本框
  JButton yesBtn, exitBtn;//创建两个选择按钮，“确定”与“退出”
  JPanel panel1 = new JPanel();
  public BookDelete() {
    super("删除书籍信息");
    c = getContentPane();
    c.setLayout(new BorderLayout());//页面设置布局
    c.add(TipLabel, BorderLayout.NORTH);//显示在北面
    c.add(bookDeleteTextField, BorderLayout.CENTER);//编辑框在中间，输入书名
    yesBtn = new JButton("确定");
    exitBtn = new JButton("退出");
    yesBtn.addActionListener(this);//侦听
    exitBtn.addActionListener(this);
    panel1.add(yesBtn);//按钮增加到面板
    panel1.add(exitBtn);
    c.add(panel1, BorderLayout.SOUTH);//按钮在南面
  }
   //事件发生的处理操作
  public void actionPerformed(ActionEvent e) {
    if (e.getSource() == exitBtn) {
      this.dispose();
    }
    else if (e.getSource() == yesBtn) {
      try {
        String strSQL = "select borrowed_count from books where bookName='" +
            bookDeleteTextField.getText().trim() + "'";
        rs = db.getResult(strSQL);
        if (!rs.first()) {
          JOptionPane.showMessageDialog(null, "书库里没有你要删除的书！");
        }
        else {
          String strSql = "delete books where bookName='" +
              bookDeleteTextField.getText().trim() + "'and borrowed_count=0";
          rs.first();
          int count = rs.getInt(1);//获取第一列的值
          if (! (count == 0)) {
            JOptionPane.showMessageDialog(null, "此书还有学生没有还！\n现在还不能从书库中删除。。。");
            this.dispose();
          }
          else if (db.updateSql(strSql)>0) {
            JOptionPane.showMessageDialog(null, "删除成功！");
            db.closeConnection();
            this.dispose();
          }
          else {
            JOptionPane.showMessageDialog(null, "删除失败！");
            db.closeConnection();
            this.dispose();
          }
        }
      }
      catch (SQLException sqle) {
        System.out.println(sqle.toString());//数据库连接失败
      }
      catch (Exception ex) {
        System.out.println(ex.toString());
      }
    }
  }
}