www.pudn.com > bookstore_new.rar > BookDBEJBImpl.java

 
 
package mypack; 
 
import java.util.*; 
import java.sql.*; 
import javax.sql.*; 
import javax.naming.*; 
import javax.ejb.*; 
 
 
public class BookDBEJBImpl implements SessionBean { 
   private ArrayList books = null; 
   private Connection con = null; 
   private String dbUrl =  "jdbc:mysql://localhost:3306/BookDB"; 
  private String dbUser="dbuser"; 
  private String dbPwd="1234"; 
 
 
 
   // implementation of create and remove remote methods 
 
  public void ejbCreate() throws CreateException { 
    try  { 
      Class.forName("com.mysql.jdbc.Driver"); 
      con = java.sql.DriverManager.getConnection(dbUrl,dbUser,dbPwd); 
 
    } catch (Exception ex) { 
      throw new CreateException("Couldn't create bean: " + ex.getMessage()); 
    } 
    books = new ArrayList(); 
  } 
 
  public void ejbRemove() throws EJBException { 
    try { 
      con.close(); 
    } catch (SQLException ex) { 
      throw new EJBException("unsetEntityContext: " + ex.getMessage()); 
    } 
    con = null; 
    books = null; 
  } 
 
  public BookDBEJBImpl() {} 
  public void ejbActivate() {} 
  public void ejbPassivate() {} 
  public void setSessionContext(SessionContext sc) {} 
 
    // remote methods 
 
  public int getNumberOfBooks()  { 
    books = new ArrayList(); 
    try { 
      String selectStatement = "select * " + "from books"; 
      PreparedStatement prepStmt = con.prepareStatement(selectStatement); 
      ResultSet rs = prepStmt.executeQuery(); 
 
      while (rs.next()) { 
        BookDetails bd = new BookDetails(rs.getString(1), rs.getString(2), rs.getString(3), 
         rs.getFloat(4), rs.getInt(5), rs.getString(6),rs.getInt(7)); 
        if (rs.getInt(8) > 0) 
          books.add(bd); 
      } 
      prepStmt.close(); 
    } catch (SQLException ex) { 
      ex.printStackTrace(); 
    } 
 
    return books.size(); 
  } 
 
  public Collection getBooks() { 
    books = new ArrayList(); 
    try { 
      String selectStatement = "select * " + "from books"; 
      PreparedStatement prepStmt = con.prepareStatement(selectStatement); 
      ResultSet rs = prepStmt.executeQuery(); 
 
      while (rs.next()) { 
 
        BookDetails bd = new BookDetails(rs.getString(1), rs.getString(2), rs.getString(3), 
           rs.getFloat(4), rs.getInt(5), rs.getString(6),rs.getInt(7)); 
        books.add(bd); 
      } 
 
      prepStmt.close(); 
    } catch (SQLException ex) { 
      ex.printStackTrace(); 
    } 
 
    Collections.sort(books); 
    return books; 
  } 
  private String bookId; 
  public void setBookId(String bookId){ 
    this.bookId=bookId; 
  } 
  public BookDetails getBookDetails()  { 
     return getBookDetails(bookId); 
  } 
  public BookDetails getBookDetails(String bookId)  { 
    try { 
      String selectStatement = "select * " + "from books where id = ? "; 
      PreparedStatement prepStmt = con.prepareStatement(selectStatement); 
      prepStmt.setString(1, bookId); 
      ResultSet rs = prepStmt.executeQuery(); 
 
      if (rs.next()) { 
        BookDetails bd = new BookDetails(rs.getString(1), rs.getString(2), rs.getString(3), 
          rs.getFloat(4), rs.getInt(5), rs.getString(6),rs.getInt(7)); 
        prepStmt.close(); 
 
        return bd; 
      } 
      else { 
        prepStmt.close(); 
        return null; 
      } 
    } catch (SQLException ex) { 
      return null; 
    } 
  } 
 
  public void buyBooks(ShoppingCart cart) { 
    Collection items = cart.getItems(); 
    Iterator i = items.iterator(); 
    try { 
      con.setAutoCommit(false); 
      while (i.hasNext()) { 
        ShoppingCartItem sci = (ShoppingCartItem)i.next(); 
        BookDetails bd = (BookDetails)sci.getItem(); 
        String id = bd.getBookId(); 
        int quantity = sci.getQuantity(); 
        buyBook(id, quantity); 
      } 
      con.commit(); 
      con.setAutoCommit(true); 
 
    } catch (Exception ex) { 
      ex.printStackTrace(); 
    } 
  } 
 
 
  public boolean buyBook(String bookId, int quantity)  { 
    try { 
       String selectStatement = "select * " + "from books where id = ? "; 
      PreparedStatement prepStmt = con.prepareStatement(selectStatement); 
      prepStmt.setString(1, bookId); 
      ResultSet rs = prepStmt.executeQuery(); 
      if (rs.next()) { 
        prepStmt.close(); 
          String updateStatement = 
                  "update books set saleamount = saleamount + ? where id = ?"; 
          prepStmt = con.prepareStatement(updateStatement); 
          prepStmt.setInt(1, quantity); 
          prepStmt.setString(2, bookId); 
          prepStmt.executeUpdate(); 
          prepStmt.close(); 
       } 
    } catch (Exception ex) {ex.printStackTrace();} 
 
     return false; 
  } 
 
}