/**
 * 数据库连接工具类
 */
public class ConnectionUtils {

    // 连接所需的固定参数
    private static String driver = "com.mysql.jdbc.Driver";
    private static String url = "jdbc:mysql://127.0.0.1:3306/scholar-system?useUnicode=true&characterEncoding=utf-8&useSSL=false";
    private static String user = "root";
    private static String password = "Easy@0122";

    // 初始化的时候加载去的弄
    static {
        try {
            Class.forName(driver);
        } catch (ClassNotFoundException e) {
            throw new ExceptionInInitializerError(e);
        }
    }

    /**
     * 获取连接
     */
    public static Connection getConnection() throws SQLException {
        return DriverManager.getConnection(url, user, password);
    }

    /**
     * 释放连接
     */
    public static void releaseConnection(Connection conn) {
        if (conn != null)
            try {
                conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
    }
}
接下来，就可以利用DbUtils开发数据访问类了，此处我们以MenuDao的开发为例说明下，其他类几乎一模一样。


/**
 * 菜单数据访问类
 */
public class MenuDao {
    /**
     * 新增
     */
    public void insert(Menu menu) throws Exception {
        Connection conn = ConnectionUtils.getConnection();
        String sql = "insert into menu(name,path)values(?,?)";
        Object[] params = { menu.getName(), menu.getPath() };
        QueryRunner runner = new QueryRunner();
        runner.update(conn, sql, params);
        ConnectionUtils.releaseConnection(conn);
    }

    /**
     * 移除
     */
    public void deleteById(String id) throws Exception {
        Connection conn = ConnectionUtils.getConnection();
        String sql = "delete from menu where id =?";
        Object[] params = { id };
        QueryRunner runner = new QueryRunner();
        runner.update(conn, sql, params);
        ConnectionUtils.releaseConnection(conn);
    }

    /**
     * 更新
     */
    public void update(Menu menu) throws Exception {
        Connection conn = ConnectionUtils.getConnection();
        String sql = "update menu set name=?,path=? where id =?";
        Object[] params = { menu.getName(), menu.getPath(), menu.getId() };
        QueryRunner runner = new QueryRunner();
        runner.update(conn, sql, params);
        ConnectionUtils.releaseConnection(conn);
    }

    /**
     * 获取一个
     */
    public Menu getById(String id) throws Exception {
        Connection conn = ConnectionUtils.getConnection();
        String sql = "select * from menu where id =?";
        Object[] params = { id };
        QueryRunner runner = new QueryRunner();
        Menu menu = (Menu) runner.query(conn, sql, new BeanHandler<Menu>(Menu.class), params);
        ConnectionUtils.releaseConnection(conn);
        return menu;
    }

    /**
     * 获取全部
     */
    public List<Menu> getAll() throws Exception {
        Connection conn = ConnectionUtils.getConnection();
        String sql = "select * from menu ";
        QueryRunner runner = new QueryRunner();
        List<Menu> menus = runner.query(conn, sql, new BeanListHandler<Menu>(Menu.class));
        ConnectionUtils.releaseConnection(conn);
        return menus;
    }

    /**
     * 获取数量
     */
    public int getCount() throws Exception {
        Connection conn = ConnectionUtils.getConnection();
        String sql = "select count(id) from menu ";
        QueryRunner runner = new QueryRunner();
        Number number = (Number) runner.query(conn, sql, new ScalarHandler());
        int value = number.intValue();
        ConnectionUtils.releaseConnection(conn);
        return value;
    }

    /**
     * 分页查询
     */
    public List<Menu> getPage(int page, int rows) throws Exception {
        Connection conn = ConnectionUtils.getConnection();
        String sql = "select * from menu limit ?,?";
        QueryRunner runner = new QueryRunner();
        Object[] params = { (page - 1) * rows, rows };
        List<Menu> menus = runner.query(conn, sql, new BeanListHandler<Menu>(Menu.class), params);
        ConnectionUtils.releaseConnection(conn);
        return menus;
    }
}
操作模式非常简单，获取连接后，通过DbUtils提供的类库进行增删改查操作，然后关闭连接即可。

5. 测试验证
开发一个测试类进行验证：

public class MenuTest {
    public static void main(String[] args) throws Exception {
        MenuDao menuDao = new MenuDao();
        Menu addMenu = new Menu();
        addMenu.setName("菜单xxx");
        addMenu.setPath("/xxx");
        menuDao.insert(addMenu);

        Menu updateMenu = new Menu();
        updateMenu.setId("1");
        updateMenu.setName("菜单yyy");
        updateMenu.setPath("/yyy");
        menuDao.update(updateMenu);

        Menu queryMenu = menuDao.getById("1");
        System.out.println(queryMenu.getName());

        System.out.println(menuDao.getAll().size());
        System.out.println(menuDao.getCount());
        System.out.println(menuDao.getPage(1, 10).size());

        menuDao.deleteById("2");
    }
}

输出结果如下

菜单yyy

大功告成！说实话小项目用Apache Common DbUtils已经足够简洁完美了，非常推荐使用！