database.java

模拟股票交易市场设计的股票交易系统。采用软件工程思想设计

/*
 * dataBase.java
 *
 * Created on 2003年5月1日, 上午9:19
 */

/**
 *
 * @author  超级用户
 */
import java.io.*;
import java.lang.*;
public class dataBase {
    
    public dataBase() {
    }
    
    public boolean checkExist(java.lang.String username) {
        File f=new File("USER/"+username+".txt");
        return(f.exists());
    }
    public void userWrite(java.lang.String username, java.lang.String password, double money) {
        try{
            RandomAccessFile rf=new RandomAccessFile("USER/"+username+".txt","rw");
            rf.seek(0*60);
            rf.writeUTF(password);
            rf.seek(0*60+30);
            rf.writeDouble(money);
            rf.close();
        }
        catch(Exception e)
        {
        }
    }
    
    public void pStockWrite(java.lang.String username, java.lang.String ps_name, int ps_num_have, double ps_ave_cost, int pos) {
        int Pos=pos+1;
        try{ 
            RandomAccessFile rf=new RandomAccessFile("USER/"+username+".txt","rw");
            int i=Pos*60;
            rf.seek(i);
            rf.writeUTF(ps_name);
            rf.seek(i+20);
            rf.writeInt(ps_num_have);
            rf.seek(i+40);
            rf.writeDouble(ps_ave_cost);
            rf.close();
        }
        catch(Exception e)
        {
        }
    }
    
    public String getPassword(java.lang.String username) {
        String str=null;
        RandomAccessFile rf=null;
        try{
            rf=new RandomAccessFile("USER/"+username+".txt","rw");
            rf.seek(0*60);
            str=rf.readUTF();
            rf.close();
        }  
        catch(Exception e)
    	{
    	}
        return str;
    }
    
    public double getMoney(java.lang.String username) {
        double money=0;
        RandomAccessFile rf=null;
        try{
            rf=new RandomAccessFile("USER/"+username+".txt","rw");
            rf.seek(0*60+30);
            money=rf.readDouble();
            rf.close();
        }  
        catch(Exception e)
    	{
    	}
        return money;
    }
    
    public void newuser(java.lang.String username, java.lang.String password) {
        File f=new File("USER/"+username+".txt");
        try{
            f.createNewFile();
        }
        catch(Exception e)
        {
        }
        userWrite(username, password,0);
    }
    
    public String getStockName(java.lang.String username, int pos) {
        String str=null;
        int Pos=pos+1;
        RandomAccessFile rf=null;
        try{
            rf=new RandomAccessFile("USER/"+username+".txt","rw");
            rf.seek(Pos*60);
            str=rf.readUTF();
            rf.close();
        }
        catch(Exception e)
        {
        }
        return str;
    }
    
    public int getStockNum_have(java.lang.String username, int pos) {
        int i=0;
        int Pos=pos+1;
        RandomAccessFile rf=null;
        try{
            rf=new RandomAccessFile("USER/"+username+".txt","rw");
            rf.seek(Pos*60+20);
            i=rf.readInt();
            rf.close();
        }
         catch(Exception e)
        {
        }
            return i;
    }
    
    public double getStockAve_cost(java.lang.String username, int pos) {
        double d=0;
        int Pos=pos+1;
        RandomAccessFile rf=null;
        try{
            rf=new RandomAccessFile("USER/"+username+".txt","rw");
            rf.seek(Pos*60+40);
            d=rf.readDouble();
            rf.close();
        }
         catch(Exception e)
        {
        }
        return d;
    }
    
    public int checkPassword(java.lang.String username, java.lang.String password) {
        String str=getPassword(username);
        int i=str.compareTo(password);
        return i;
    }
    
    public void clear(java.lang.String username) {
        File f=null;
        try{
            f=new File("USER/"+username+".txt");
             //通过删除再建立，达到将原文档清空的目的
            f.delete();
            f.createNewFile();
        }
        catch(Exception e)
        {}
    }
    
    public int getItemNum(java.lang.String username) {
        int i=0;
        try{
            RandomAccessFile rf=new RandomAccessFile("USER/"+username+".txt","rw");
            rf.seek(i*60);
            String str=rf.readUTF();
            while(str!=null)
            {
                i++;
                rf.seek(i*80);
                str=rf.readUTF();
            }
            rf.close();
            }
            catch(Exception e)
            {
    		
            }
        return i-1;
    }
    public int getStockNum(java.lang.String stock_name){//stock_name that is file_name
        int num=0;
        try
        {
            RandomAccessFile rf=new RandomAccessFile("STOCK/"+stock_name+".txt","rw");
            rf.seek(0);
            num=rf.readInt();
            rf.close();
        }
        catch(Exception e)
            {
    		
            }
        return num;
    }
    
    public double stockRead(java.lang.String stock_name, int pos) {
        int Pos=pos+1;
        double num=0;
        try
        {
            RandomAccessFile rf=new RandomAccessFile("STOCK/"+stock_name+".txt","rw");
            rf.seek(Pos*60);
            num=rf.readDouble();
            rf.close();
        }
        catch(Exception e)
            {
    		
            }
        return num;
    }    
   
    public int getRecordNum() {
        int num=0;
        try{
            RandomAccessFile rf=new RandomAccessFile("STOCK/RECORD.txt","rw");
            rf.seek(0);
            num=rf.readInt();
        }
        catch(Exception e)
        {}
        return num;
    }
    
    public int getNumOnSall(String stock_name) 
    {
        int num=0;
        try
        {
            RandomAccessFile rf=new RandomAccessFile("STOCK/"+stock_name+".txt","rw");
            rf.seek(30);
            num=rf.readInt();
            rf.close();
        }
        catch(Exception e)
            {
    		
            }
        return num;
    }
}