useraccounterbean.java

来自「开发无状态.有状态的会话Bean,可以结合有电子工业出版社的J2E教材学习」· Java 代码 · 共 156 行

package banksystem;

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

public class UserAccountBean implements SessionBean{
	private SessionContext sessionContext;
	private String id=null;
	private String password=null;
	private Connection conn=null;
	
	public void ejbCreate(String id,String password)
		throws CreateException,SQLException,NamingException{
		InitialContext ctx=new InitialContext();
		DateSource ds=(DataSource)ctx.lookup("sqlserver");
		conn=ds.getConnection();
	
		PrepareedStatement pstmt=conn.prepareStatement("SELECT password FROM accout WHERE id=?");
		pstmt.setString(1,id);
		ResultSet rs=pstmt.executeQuery();
	
		if(rs.next()){
			String pw=rs.getString("password");
			if (password.equals(pw)){
				this.id=id;
				this.password=password;
				return;
			}
			esle{
				conn.close();
				conn=null;
				thow new CreateException("password Error!");
			}
		}
		else{
			conn.close();
			conn=null;
			thow new CreateException("Incorrect User Id!");
		}
	}
	
	public void ejbRemove(){
		try{
			id=null;
			password=null;
			conn.close();
			conn=null;
		}
		catch(Exception ex){
			ex.printStackTrace();
		}
	}
	
	public void ejbActivate(){
		try{
			InitialContext ctx=new InitialContext();
			DateSource ds=(DataSource)ctx.lookup("sqlserver");
			conn=ds.getConnection();
		}
		catch(Exception ex){
			ex.printStackTrace();
		}
	}
	
	public void ejbPassivate(){
		try{
			conn.close();
			conn=null;
		}
		catch(Exception ex){
			ex.printTrace();
		}
	}
	
	public void setSessionContext(SessionContext sessionContext){
		this.sessionContext=sessionContext;
	}
	
	public double Balance()throws SQLException{
		PreparedStatement pstmt=null;
		pstmt=conn.preparedStatement("SELECT balance FROM account WHERE id=?");
		pstmt.setString(1,id);
		ResultSet rs=pstmt.excuteQuery();
		if(rs.next()){
			double balance=rs.getDouble("balance");
			pstmt.close();
			return balance;
		}
		else{
			pstmt.close();
			throw new SQLException("None user id can be found!");
		}
	}
	
	
	public void Withdraw(double amount)throws SQLException{
		PreparedStatement pstmt=null;
		pstmt=conn.preparedStatement("UPDATE account SET balance=balance-? WHERE id=?");
		pstmt.setDouble(1,amount);
		pstmt.setString(2,id);
		if(pstmt.executeUpdate()==1){
			pstmt.close();
			return;
		}
		else{
			pstmt.close();
			throw new SQLException("Can't update the database!");
		}
	}
	
	public void Deposit(double amount)throws SQLException{
		PreparedStatement pstmt=null;
		pstmt=conn.preparedStatement("UPDATE account SET balance=balance+? WHERE id=?");
		pstmt.setDouble(1,amount);
		pstmt.setString(2,id);
		if(pstmt.executeUpdate()==1){
			pstmt.close();
			return;
		}
		else{
			pstmt.close();
			throw new SQLException("Can't update the database!(deposit)");
		}	
	}
	
	public void Transfer(String toId,double amount)throws SQLException{
		PreparedStatement pstmt=null;
		pstmt=conn.preparedStatement("UPDATE account SET balance=balance-? WHERE id=?");
		pstmt.setDouble(1,amount);
		pstmt.setString(2,id);
		if(pstmt.executeUpdate()==1){
			pstmt.close();
			return;
		}
		else{
			pstmt.close();
			throw new SQLException("Can't update the database!");
		}

		pstmt=conn.preparedStatement("UPDATE account SET balance=balance+? WHERE id=?");
		pstmt.setDouble(1,amount);
		pstmt.setString(2,toId);
		if(pstmt.executeUpdate()==1){
			pstmt.close();
			return;
		}
		else{
			pstmt.close();
			throw new SQLException("Can't update the database!(deposit)");
		}	
	}
}