大三学习javaweb的作业.zip

package book; import cn.edu.swu.db.DBEngine; import cn.edu.swu.db.RecordVisitor; import cn.edu.swu.user.User; import java.sql.ResultSet; import java.sql.SQLException; import java.util.List; public class BookRepo { private static BookRepo instance = new BookRepo(); private BookRepo(){ } public static BookRepo getInstance() { return instance; } public void saveBook(Book book) throws SQLException { if (book.getId() > 0) { this.updateBook(book); } else { this.insertBook(book); } } private void insertBook(Book book) throws SQLException { String template = "INSERT INTO `book`(`name`, `author`, `price`, `describe`) " + "VALUES (\"%s\", \"%s\", %s, \"%s\")"; String sql = String.format(template, book.getName(), book.getAuthor(), book.getPrice(), book.getDescribe()); DBEngine.getInstance().execute(sql); } private void updateBook(Book book) throws SQLException { String template = "UPDATE `book` SET `name`=\"%s\", `author`=\"%s\", `price`=%s, `describe`=\"%s\" " + "WHERE `id`=%s"; String sql = String.format(template, book.getName(), book.getAuthor(), book.getPrice(), book.getDescribe(), book.getId()); DBEngine.getInstance().execute(sql); } public void deleteBook(Book book) throws SQLException { String template = "DELETE FROM `book` WHERE `id` = %s"; String sql = String.format(template, book.getId()); DBEngine.getInstance().execute(sql); } public void deleteBook(Long id) throws SQLException { String template = "DELETE FROM `book` WHERE `id` = %s"; String sql = String.format(template, id); DBEngine.getInstance().execute(sql); } public List<Book> getAll() throws SQLException { String sql = "SELECT `id`, `name`, `author`, `price`, `describe` FROM `book`"; return DBEngine.getInstance().query(sql, new RecordVisitor<Book>() { @Override public Book visit(ResultSet rs) throws SQLException { return BookRepo.getBookFromResultset(rs); } }); } public Book getById(String id) throws SQLException { String sql = "SELECT * FROM `book` WHERE `id` = %s"; List<Book> books = DBEngine.getInstance().query( String.format(sql, id), new RecordVisitor<Book>() { @Override public Book visit(ResultSet rs) throws SQLException { return BookRepo.getBookFromResultset(rs); } }); return books.size() == 0 ? null : books.get(0); } private static Book getBookFromResultset(ResultSet rs) throws SQLException { Book book = new Book(); book.setId(rs.getLong("id")); book.setName(rs.getString("name")); book.setAuthor(rs.getString("author")); book.setDescribe(rs.getString("describe")); book.setPrice(rs.getFloat("price")); return book; } }