warehousebean.java

java的一系列产品中包括jsme,jmse,j2ee,本文件提供j2ee实现的源代码.

package warehouse;

import java.util.*;
import javax.ejb.*;
import java.sql.*;
import javax.sql.*;
import javax.naming.*;

public class WarehouseBean implements SessionBean {

   private SessionContext context;
   private Connection con;
   private String dbName = "java:comp/env/jdbc/WarehouseDB";

   public void ship (String productId, String orderId) {

      try {
         con.setAutoCommit(false);
         updateOrderItem(productId,orderId);
         con.commit();
      } catch (Exception ex) {
          try {
             con.rollback();
             throw new EJBException("Transaction failed: " + ex.getMessage());
          } catch (SQLException sqx) {
              throw new EJBException("Rollback failed: " + sqx.getMessage());
          }
      }
   } 

   public String getStatus(String productId, String orderId) {

      try {
         return selectStatus(productId, orderId);
      } catch (SQLException ex) {
          throw new EJBException 
             ("Unable to fetch status due to SQLException: " 
             + ex.getMessage());
      }
   }

   public void ejbCreate() throws CreateException {

      try {
         makeConnection();
      } catch (Exception ex) {
          throw new CreateException(ex.getMessage());
      }
     
   }

   public void ejbRemove()  {

      try {
         con.close();
      } catch (SQLException ex) {
          throw new EJBException(ex.getMessage());
      }
   }

   public void ejbActivate()  {

      try {
         makeConnection();
      } catch (Exception ex) {
          throw new EJBException(ex.getMessage());
      }
   }

   public void ejbPassivate()  {

      try {
         con.close();
      } catch (SQLException ex) {
          throw new EJBException(ex.getMessage());
      }
   }

   public void setSessionContext(SessionContext context) {

      this.context = context;
   }

   public WarehouseBean() {}

/********************* Database Routines ***********************/

   private String selectStatus(String productId, String orderId)
      throws SQLException {

      String result;

      String selectStatement =
            "select status " +
            "from t_OrderItem where productid = ? " +
            "and orderid = ?";
      PreparedStatement prepStmt =
            con.prepareStatement(selectStatement);

      prepStmt.setString(1, productId);
      prepStmt.setString(2, orderId);

      ResultSet rs = prepStmt.executeQuery();

      if (rs.next()) {
         result = rs.getString(1);
      }
      else {
         result = "No rows found.";
      }

      prepStmt.close();
      return result;
   }

   private void updateOrderItem(String productId, String orderId)
      throws SQLException {

      String updateStatement =
            "update t_OrderItem set status =  'shipped' " +
            "where productid = ? " +
            "and orderid = ?";

      PreparedStatement prepStmt = 
            con.prepareStatement(updateStatement);

      prepStmt.setString(1, productId);
      prepStmt.setString(2, orderId);
      prepStmt.executeUpdate();
      prepStmt.close();
   }
   
    private void makeConnection() 
      throws NamingException, SQLException {

      InitialContext ic = new InitialContext();
      DataSource ds = (DataSource) ic.lookup(dbName);
      con =  ds.getConnection();
  }
} // WarehouseBean