db.java

是一个用VB编写得银行ATM机交易的程序

/*
 * DB.java
 *
 * Created on 2008年1月11日, 上午9:33
 *
 * To change this template, choose Tools | Template Manager
 * and open the template in the editor.
 */

package com.myapp.struts;

/**
 *
 * @author Administrator
 */
import java.sql.*;
import java.util.ArrayList;
public class DB {
    private static String url="jdbc:mysql://localhost:3306/paysystem?user=root&password=root";
	
	 Connection conn=null;
	 Statement statement=null;
	 ResultSet rs=null;
   //这里数据库连接必需放在方法里，要不然会报错。
    public boolean  CONN(){
    	try{
    	Class.forName("com.mysql.jdbc.Driver");//.newInstance();
    	conn= DriverManager.getConnection(url);
        statement = conn.createStatement();
        return true;
    	}catch(Exception e){return false;}
    }
    
    public ResultSet Select(String sql){
            if(this.CONN())
            {
                try{
                rs = statement.executeQuery(sql);
                }
                catch(Exception e){}
                return rs;
            }
            else return null;
    }
    public boolean ExcuteSql(String sql){
    	boolean x=false;
        if(this.CONN())
        {
            try{
            statement.executeUpdate(sql);
            x=true;
            }catch(Exception e){e.printStackTrace();}
        }
          return x;
    }

public boolean ExcuteTrans(ArrayList al) {
        boolean x=false;
        if(this.CONN()) {
            try{
                conn.setAutoCommit(false);
                for(int i=0;i<al.size();i++) {
                    String y = al.get(i).toString();
                    statement.execute(y);
                    
                }
                conn.commit();
                conn.setAutoCommit(true);
                x=true;
            }catch(Exception e){
                try {
                    conn.rollback();
                    conn.setAutoCommit(true);
                }catch(Exception ex){}
                
            }
            
          
        }
          return x;
    }
    
    public void DBClose(){
    	try{
    	if(statement!=null){statement.close();}
    	if(conn!=null){conn.close();}
    	}catch(Exception e){}
    }
}