图书管理系统用Java写

好的，这里提供一个基于Java Swing和MySQL数据库的简单图书管理系统示例代码，包含添加、删除、修改和查询图书的功能：

import javax.swing.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.sql.*;

public class BookManagementSystem extends JFrame {
    private JTable table;
    private JTextField idField;
    private JTextField titleField;
    private JTextField authorField;
    private JTextField yearField;
    private JButton addButton;
    private JButton deleteButton;
    private JButton updateButton;
    private JButton searchButton;

    private Connection conn;

    public BookManagementSystem() {
        setTitle("图书管理系统");
        setSize(600, 400);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        // 连接数据库
        try {
            Class.forName("com.mysql.jdbc.Driver");
            String url = "jdbc:mysql://localhost:3306/library";
            String user = "root";
            String password = "password";
            conn = DriverManager.getConnection(url, user, password);
        } catch (Exception e) {
            e.printStackTrace();
            JOptionPane.showMessageDialog(this, "连接数据库失败！");
        }

        // 创建UI界面
        JPanel panel = new JPanel();
        add(panel);

        JLabel idLabel = new JLabel("ID:");
        panel.add(idLabel);
        idField = new JTextField(10);
        panel.add(idField);

        JLabel titleLabel = new JLabel("Title:");
        panel.add(titleLabel);
        titleField = new JTextField(20);
        panel.add(titleField);

        JLabel authorLabel = new JLabel("Author:");
        panel.add(authorLabel);
        authorField = new JTextField(10);
        panel.add(authorField);

        JLabel yearLabel = new JLabel("Year:");
        panel.add(yearLabel);
        yearField = new JTextField(4);
        panel.add(yearField);

        addButton = new JButton("添加");
        addButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                String title = titleField.getText();
                String author = authorField.getText();
                int year = Integer.parseInt(yearField.getText());
                addBook(title, author, year);
                refreshTable();
                JOptionPane.showMessageDialog(BookManagementSystem.this, "添加成功！");
            }
        });
        panel.add(addButton);

        deleteButton = new JButton("删除");
        deleteButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                int id = Integer.parseInt(idField.getText());
                removeBook(id);
                refreshTable();
                JOptionPane.showMessageDialog(BookManagementSystem.this, "删除成功！");
            }
        });
        panel.add(deleteButton);

        updateButton = new JButton("修改");
        updateButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                int id = Integer.parseInt(idField.getText());
                String title = titleField.getText();
                String author = authorField.getText();
                int year = Integer.parseInt(yearField.getText());
                updateBook(id, title, author, year);
                refreshTable();
                JOptionPane.showMessageDialog(BookManagementSystem.this, "修改成功！");
            }
        });
        panel.add(updateButton);

        searchButton = new JButton("查询");
        searchButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                String title = titleField.getText();
                String author = authorField.getText();
                int year = 0;
                if (!yearField.getText().isEmpty()) {
                    year = Integer.parseInt(yearField.getText());
                }
                searchBooks(title, author, year);
            }
        });
        panel.add(searchButton);

        // 创建表格
        table = new JTable();
        JScrollPane tablePane = new JScrollPane(table);
        tablePane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
        panel.add(tablePane);

        // 刷新表格
        refreshTable();
    }

    // 添加图书
    private void addBook(String title, String author, int year) {
        try {
            PreparedStatement stmt = conn.prepareStatement("INSERT INTO books (title, author, year) VALUES (?, ?, ?)");
            stmt.setString(1, title);
            stmt.setString(2, author);
            stmt.setInt(3, year);
            stmt.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
            JOptionPane.showMessageDialog(this, "添加失败！");
        }
    }

    // 删除图书
    private void removeBook(int id) {
        try {
            PreparedStatement stmt = conn.prepareStatement("DELETE FROM books WHERE id=?");
            stmt.setInt(1, id);
            stmt.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
            JOptionPane.showMessageDialog(this, "删除失败！");
        }
    }

    // 修改图书
    private void updateBook(int id, String title, String author, int year) {
        try {
            PreparedStatement stmt = conn.prepareStatement("UPDATE books SET title=?, author=?, year=? WHERE id=?");
            stmt.setString(1, title);
            stmt.setString(2, author);
            stmt.setInt(3, year);
            stmt.setInt(4, id);
            stmt.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
            JOptionPane.showMessageDialog(this, "修改失败！");
        }
    }

    // 查询图书
    private void searchBooks(String title, String author, int year) {
        try {
            String query = "SELECT * FROM books WHERE 1=1";
            if (!title.isEmpty()) {
                query += " AND title LIKE '%" + title + "%'";
            }
            if (!author.isEmpty()) {
                query += " AND author LIKE '%" + author + "%'";
            }
            if (year != 0) {
                query += " AND year=" + year;
            }
            Statement stmt = conn.createStatement();
            ResultSet rs = stmt.executeQuery(query);
            table.setModel(DbUtils.resultSetToTableModel(rs));
        } catch (SQLException e) {
            e.printStackTrace();
            JOptionPane.showMessageDialog(this, "查询失败！");
        }
    }

    // 刷新表格
    private void refreshTable() {
        try {
            Statement stmt = conn.createStatement();
            ResultSet rs = stmt.executeQuery("SELECT * FROM books");
            table.setModel(DbUtils.resultSetToTableModel(rs));
        } catch (SQLException e) {
            e.printStackTrace();
            JOptionPane.showMessageDialog(this, "刷新表格失败！");
        }
    }

    public static void main(String[] args) {
        BookManagementSystem system = new BookManagementSystem();
        system.setVisible(true);
    }
}

这个系统主要使用了Java Swing UI库来创建UI界面，使用了JTable来显示图书数据，使用了MySQL数据库来存储图书信息。可以根据需要进行修改和扩展。