MVC模式范例 jsp的三层架构

/** * mvc中的控制器材,C */ import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; import java.util.ArrayList; public class BookDao implements Dao { private Connection con = null; private String url, username, password; private String driverclass; private Statement gs = null; private PreparedStatement statement = null; private ResultSet result = null; public int addBook(Book book) throws Exception { statement = con.prepareStatement("INSERT INTO book (name,price,image,data,page,number) VALUES(?,?,?,?,?,?)"); statement.setString(1, book.getName()); statement.setDouble(2, book.getPrice()); statement.setString(3, book.getImage()); statement.setString(4, book.getData()); statement.setInt(5, book.getPage()); statement.setInt(6, book.getNumber()); int x=statement.executeUpdate(); return x; } public int delBook(int id) throws Exception { gs = con.createStatement(); int x=gs.executeUpdate("DELETE FROM book WHERE id=" + id); return x; } public void close() { try { if (statement != null) { statement.close(); } if (gs != null) { gs.close(); } if (!con.isClosed()) { con.close(); } } catch (SQLException e) { e.printStackTrace(); } } public Book listBook(String name) throws Exception { if (gs == null) { gs = con.createStatement(); } Book book = new Book(); result = gs.executeQuery("SELECT * FROM book WHERE name='" + name+"'"); while (result.next()) { book.setId(result.getInt(1)); book.setName(result.getString(2)); book.setPrice(result.getDouble(3)); book.setImage(result.getString(3)); book.setData(result.getString(5)); book.setPage(result.getInt(6)); book.setNumber(result.getInt(7)); } return book; } public ArrayList listBooks() throws Exception { ArrayList<Book> books = new ArrayList<Book>(); if (gs == null) { gs = con.createStatement(); } result = gs.executeQuery("SELECT * FROM book"); while (result.next()) { Book book = new Book(); book.setId(result.getInt(1)); book.setName(result.getString(2)); book.setPrice(result.getDouble(3)); book.setImage(result.getString(4)); book.setData(result.getString(5)); book.setPage(result.getInt(6)); book.setNumber(result.getInt(7)); books.add(book); } return books; } public int updateBook(Book book, int id) throws Exception { gs = con.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_UPDATABLE); result = gs.executeQuery("SELECT * FROM book WHERE id=" + id); if (result.next()) { result.first(); result.updateString("name", book.getName()); result.updateDouble("price", book.getPrice()); result.updateString("image", book.getImage()); result.updateString("data", book.getData()); result.updateInt("page", book.getPage()); result.updateInt("number", book.getNumber()); result.updateRow(); } return 0; } public Connection getCon() { return con; } public void setCon(Connection con) { this.con = con; } public String getUrl() { return url; } public void setUrl(String url) { this.url = url; } public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } public String getDriverclass() { return driverclass; } public void setDriverclass(String driverclass) { this.driverclass = driverclass; } public Connection setCon() { try { Class.forName(getDriverclass()); con = DriverManager.getConnection(url, username, password); } catch (ClassNotFoundException e) { } catch (SQLException e) { e.printStackTrace(); } return con; } }