employeebean.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 employee;

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

public class EmployeeBean implements SessionBean, SessionSynchronization {
   private String employeeId;
   private int empNo;
   private double salary;
   private SessionContext context;
   //or use:
   //private EJBContext context;
   private Connection con;
   private String dbName = "java:comp/env/jdbc/employeeDB";

   public void salaryToSave(int employeeNo,double amount) throws EmployeeNoException{
      empNo= employeeNo;
      salary = amount;
      double cur_Salary;
      try{
         cur_Salary=getCurSalary(empNo);
         if (cur_Salary > 8000.0){
            context.setRollbackOnly();
            System.out.println("the salary is enough hign,don't need to add");
            //throw new EmployeeNoException();
         }
         updateSalary(empNo,salary);
      }catch (SQLException ex){
          throw new EJBException 
             ("Transaction failed due to SQLException: " 
             + ex.getMessage());
      }
   }
   
   public void ejbCreate(String id) throws CreateException{

      employeeId = id;
      try{
         makeConnection();
         //checkingBalance = selectChecking();         
      }catch (Exception ex){
          throw new CreateException(ex.getMessage());
      }
   }

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

   public void ejbActivate(){

      try {
         makeConnection();
      } catch (Exception ex){
          throw new EJBException("ejbActivate Exception: " + ex.getMessage());
      }
   }

   public void ejbPassivate(){

      try {
        con.close();
      } catch (SQLException ex){
          throw new EJBException("ejbPassivate Exception: " + ex.getMessage());
      }
   }


   public void setSessionContext(SessionContext context) {
      this.context = context;
   }

   public void afterBegin(){
      System.out.println("afterBegin()");         
   }

   public void beforeCompletion() {

      System.out.println("beforeCompletion()");
   }

   public void afterCompletion(boolean committed) {

      System.out.println("afterCompletion: " + committed);
      /*if (committed == false) {
         ......
      }*/
   }

   public EmployeeBean() {}

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

   private double getCurSalary(int emp_No) throws SQLException {
      double theSalary=0.0;
      ResultSet rs;
      Statement stmt=con.createStatement();
      String selectStatement =
            "select salary from t_employee where emp_no = 2001";
      rs=stmt.executeQuery(selectStatement);
      while(rs.next()){
      	for(int j=1; j<=rs.getMetaData().getColumnCount(); j++){
					//System.out.println(rs.getObject(j));
					theSalary=rs.getDouble(j);	
					System.out.println(theSalary);
				}
			}
			stmt.close();
			return theSalary;
   }

   private void updateSalary(int empNo,double salary) throws SQLException{
   	 Statement stmt=con.createStatement();
     String updateStatement =
        "update t_employee set salary="+salary+" where emp_no="+empNo;
     stmt.executeUpdate(updateStatement);
     System.out.println("update t_employee success!");
     stmt.close();
   }
   
   public double getEmpSalary() {
      return salary;
   }
   
   private void makeConnection() 
      throws NamingException, SQLException {

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