dbbean.java

java做的一个选课系统

/*
 * @file_name  DBBean.java   
 * @create date 2007-10-17
 * @author guoxun
 * @Email [e-mail]
 */
package db;

import java.sql.*;

/**
 * @packageName db
 * @fileName DBBean.java
 * @author guoXun
 * @version 1.0
 * @date 2007-10-17
 */
public class DBBean implements DBRes{

	private Connection conn;
	private Statement st;
	private ResultSet rs;	
	
	public DBBean() {
		super();
		// TODO Auto-generated constructor stub
		this.getConnection();
		this.getStatment();
	}
	
	boolean getConnection(){
		try {
			Class.forName(driver).newInstance();
			conn=DriverManager.getConnection(url,username,password);
			//conn.setAutoCommit(false);
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			return false;
		}
		return true;
	}

	boolean getStatment(){		
		try {
			st = conn.createStatement();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			return false;			
		}
		return true;
	}
	
	public ResultSet doQuery(String sql){
		try {			
			rs=st.executeQuery(sql);
			//st.execute(sql);			
		      //rs=st.getResultSet();
		      //conn.commit();
		} catch (SQLException e) {
			// TODO Auto-generated catch block			
			e.printStackTrace();			
		}
		return rs;
	}
	
	
	public int doUpdate(String sql){
		int num=-1;
		try {
			num = st.executeUpdate(sql);
			//conn.commit();
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();			
			//conn.rollback();			
		}finally{
			this.close();			
		}
		return num;
	}
	
	public boolean close(){
		try {
			if(rs!=null)
				rs.close();
			if(st!=null)
				st.close();
			if(conn!=null && !conn.isClosed())
				conn.close();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return true;
	}
}