# one-book

**Repository Path**: zengzhaomin-coder/one-book

## Basic Information

- **Project Name**: one-book
- **Description**: book 的增删查改
- **Primary Language**: Unknown
- **License**: Not specified
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2021-11-24
- **Last Updated**: 2021-12-11

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

#### 总结
- 案例中有增删查改（crud）以及模糊查询
- 登录注册功能（用到了 session 会话） 
- 以及使用到了验证码登录的判断，验证码是根据内部自动生成的，然后用户输入正确才能登录或注册成功
- 案例虽小，五脏俱全

#### 提示
- 比如在 BookDao 中插入方法中还有更简便的方法
- 在遍历信息的情况下，我们可以换一种方式写
```aidl
public List<Book> list() throws SQLException, ClassNotFoundException {
        List<Book> books = new ArrayList<>();
        String sql = "select book_id, book_name, book_author, book_price, book_press, book_sales from book";
        System.out.println("要执行的语句是：" + sql);

        try (Connection connection = DBHelper.getConnection();
             PreparedStatement statement = connection.prepareStatement(sql);
             ResultSet resultSet = statement.executeQuery()) {
             
             while (resultSet.next()) {
                int id = resultSet.getInt(1);
                String name = resultSet.getString(2);
                String author = resultSet.getString(3);
                float price = resultSet.getFloat(4);
                String press = resultSet.getString(5);
                String sales = resultSet.getString(6);

                Book book = new Book(id, name, author, price, press, sales);
                books.add(book);
            }
            return books;
        }
```
修改之后的写法，更简便了
```aidl
    public List<Book> list() throws SQLException, ClassNotFoundException {
        List<Book> books = new ArrayList<>();
        String sql = "select book_id, book_name, book_author, book_price, book_press, book_sales from book";
        System.out.println("要执行的语句是：" + sql);

        try (Connection connection = DBHelper.getConnection();
             PreparedStatement statement = connection.prepareStatement(sql);
             ResultSet resultSet = statement.executeQuery()) {
             
            while (resultSet.next()) {
                books.add(
                    new Book(
                        resultSet.getInt(1),
                        resultSet.getString(2),
                        resultSet.getString(3),
                        resultSet.getFloat(4),
                        resultSet.getString(5),
                        resultSet.getString(6))
                );
            }
        }
        return books;
    }
```