acejb.java

USB设计的一些源码！适合与USB开发的同学！还是蛮不错的！我用过一些！

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

public class AcEJB implements EntityBean {

    private String id;
    private String date;
    private String vc;
    private String check;
    private double amount;
    private EntityContext context;
    private Connection con;
    private String dbName = "java:comp/env/jdbc/AccountDB";

  
    public String getDate() {
        return date;
    }
 
    public String getVc() {
        return vc;
    }
  
    public String getCheck() {
       return check;
    }

    public double getAmount() {
       return amount;
    }

       public String ejbCreate(String id, String date, String vc, String check, double amount) throws CreateException {
      
 	  try {
		  System.out.println("Inside ejbcreate");
    		  insertRow(id, date, vc, check, amount);
		  System.out.println("after insert row");
      	        } catch (Exception ex) {
        	        throw new EJBException("ejbCreate: " + 
            	        ex.getMessage());
     	        }

   	      this.id = id;
   	      this.date = date;
      	      this.vc =vc;
       	      this.check = check;
	      this.amount=amount;
      	      return id;
    }


   public String ejbFindByPrimaryKey(String primaryKey) 
      throws FinderException {
      boolean result;
      try {
        	 result = selectByPrimaryKey(primaryKey);
           } catch (Exception ex) {
           throw new EJBException("ejbFindByPrimaryKey: " + 
              ex.getMessage());
           }
            if (result) {
              return primaryKey;
            }
            else {
            throw new ObjectNotFoundException
            ("Row for id " + primaryKey + " not found.");
      }
   }



   public void ejbRemove() {
      try {
         deleteRow(id);
       } catch (Exception ex) {
           throw new EJBException("ejbRemove: " + 
              ex.getMessage());
       }
   } 


      public void setEntityContext(EntityContext context) {
      this.context = context;
      try {
         System.out.println("Inside setEntityContext");
         makeConnection();
          } catch (Exception ex) {
          throw new EJBException("Unable to connect to database. " +
             ex.getMessage());
      }
   }



     public void unsetEntityContext() {
      try {
         con.close();
          } catch (SQLException ex) {
          throw new EJBException("unsetEntityContext: " + ex.getMessage());
      }
   }


   public void ejbActivate() {
      id = (String)context.getPrimaryKey();
   }


   public void ejbPassivate() {
      id = null;
   }


   public void ejbLoad() {
      try {
        System.out.println("Inside ejbLoad()");
         loadRow();
        System.out.println("After loadrow() in ejbLoad()");
          } catch (Exception ex) {
           throw new EJBException("ejbLoad: " + 
              ex.getMessage());
       }
   }
   
   public void ejbStore() {
      try {
        System.out.println("Inside ejbStore()");
         storeRow();
        System.out.println("After storeRow() in ejbLoad()");
          } catch (Exception ex) {
           throw new EJBException("ejbLoad: " + 
              ex.getMessage());
       }
   }


   public void ejbPostCreate(String id, String date,  String vc, String check, double amount) { }


/***   Routines   to   access  database   ***/



   private void makeConnection() throws NamingException,  SQLException {
  InitialContext ic = new InitialContext();
  DataSource ds = (DataSource) ic.lookup(dbName);
  con =  ds.getConnection();
   }


                private void insertRow (String id, String date, String vc, String check, double amount) throws SQLException {
                  System.out.println("Inside sql insert row");
	String insertStatement =
	 "insert into Account_Holder_Transaction values ( ? , ? , ? , ?, ? )";
                 PreparedStatement prepStmt = 
                 con.prepareStatement(insertStatement);
                  System.out.println("Before id");
          	prepStmt.setString(1, id);
                  System.out.println("Before date");
          	prepStmt.setString(2, date);
                  System.out.println("Before vc");
                  prepStmt.setString(3, vc);
                  System.out.println("Before check");
                  prepStmt.setString(4, check);
                  System.out.println("Before amount");
          	prepStmt.setDouble(5, amount);
                  prepStmt.executeUpdate();
                  prepStmt.close();
   }


            private void deleteRow(String id) throws SQLException {
	 String deleteStatement =
       	"delete from Account_Holder_Transaction where cAccount_id = ? ";
     	 PreparedStatement prepStmt =
           	 con.prepareStatement(deleteStatement);
     	 prepStmt.setString(1, id);
     	 prepStmt.executeUpdate();
     	 prepStmt.close();
   }


              private boolean selectByPrimaryKey(String primaryKey) 
     	 throws SQLException {
	 String selectStatement =
            	"select cAccount_id " +
           	 "from Account_Holder  where cAccount_id = ? ";
      	PreparedStatement prepStmt = con.prepareStatement(selectStatement);
      	prepStmt.setString(1, primaryKey);
      	ResultSet rs = prepStmt.executeQuery();
      	boolean result = rs.next();
      	prepStmt.close();
      	return result;
   }


   private void loadRow() throws SQLException {
      String selectStatement =
            "select dDate_of_transaction, vcParticulars, cCheck_no, mAmount from Account_Holder_Transaction  where cAccount_id = ? ";
      	PreparedStatement prepStmt = 
      	con.prepareStatement(selectStatement);
	System.out.println("after con.prep");
     	prepStmt.setString(1, this.id);
      	ResultSet rs = prepStmt.executeQuery();
	System.out.println("After executeQuery()");
                  if (rs.next()) {
	System.out.println("Inside if");
         	this.date = rs.getString(1);
	System.out.println("After 1");
         	this.vc = rs.getString(2);
	System.out.println("After 2");
         	this.check = rs.getString(3);
	System.out.println("After 3");
         	this.amount = rs.getDouble(4);
                  prepStmt.close();
      }
      else {
         	prepStmt.close();
	throw new NoSuchEntityException("Row for id " + id +  " not found in database.");
              }
   }


   private void storeRow() throws SQLException {
      String updateStatement =
"update Account_Holder_Transaction set dDate_of_transaction =  ? , vcParticulars = ? , cCheck_no = ?, mAmount = ? where cAccount_id = ?";
      	PreparedStatement prepStmt = 
            	con.prepareStatement(updateStatement);
      	prepStmt.setString(1, date);
                  prepStmt.setString(2, vc);
                  prepStmt.setString(3, check);
      	prepStmt.setDouble(4, amount);
      	prepStmt.setString(5, id);
      	int rowCount = prepStmt.executeUpdate();
      	prepStmt.close();

     	 if (rowCount == 0) {
        	 throw new EJBException("Storing row for id " + id + " failed.");
      }
   }
}