recreation.java

来自「手机在线系统 采用Java 中的J2ME, JSP 跟MySql 运行环」· Java 代码 · 共 157 行

/**
 * @(#)Recreation.java	
 * Copyright (c) 2004-2005 wuhua of workroom Inc. All Rights Reserved.
 * @version 	1.0, 10/05/2004
 * @author 	饶荣庆
 * @author 	余煜辉
 */

package com.j2me.data;

import com.j2me.common.*;
import java.sql.*;
import java.util.*;
import java.io.*;

/**
 *此类是用来娱乐系统的数据库连接，增加用户的数据库连接类
 *此类采用JavaBean的模式，使用set,get来设置属性和获得属性，并显示在客户端。
 */
public class Recreation 
{
	private String	query; //用于查询数据的数据库语句
	private String result; //从数据库上获得结果数据并保存到的变量
	private int how;   //获得客户端传过来的数据作为判断要从数据库获得数据的字段总数；

    public Recreation()
	{
		super();
	}
    
	public void setQuery(String sql_)
	{
		query = sql_;
	}

	public void setResult(String r)
	{
		result = r;
	}

	public void setHow(int i)
	{
		how = i;
	}

	public String getQuery()
	{
		return query;
	}

	public String getResult()
	{
		return viewData();
	}

	public int getHow()
	{
		return how;
	}

	/**
	 *获得结果集方法
	 */
	public ResultSet view(String sql)
		throws SQLException, NullPointerException
	{
		ResultSet rs = null;
		DataConnect d = new DataConnect();			
		Connection con = d.getConnect(); //连接数据库

		try
		{				
			if (con == null)
		    {
				throw new NullPointerException("NullPointerException: An unknow error occurred while retrieving Recreation.");
			}	
			Statement stmt = con.createStatement();					
		    rs = stmt.executeQuery(sql);
		}
		catch(SQLException sqlexception)
		{
			throw new SQLException("SQLException: Could not execute the query.");
		}
		
			
		return rs;
	}

	public String viewData()
	{
		ResultSet rs = null;
		StringBuffer sb = new StringBuffer(); //为了提高字符串相加的性能
		try
		{
			rs = this.view(query);
		}
		catch(SQLException sqlexception)
		{
			System.out.println(sqlexception);
		}
		catch(NullPointerException n)
		{
			System.out.println(n);
		}
		catch(Exception e)
		{
			System.out.println(e);
		}
    	
		try
		{			
			//获取数据库信息
    	    while(rs.next())
		    {
			    for (int i = 1; i <= how; i++ )
			    {
				     sb = sb.append(rs.getString(i)  + "~");
			    }			
		    }
		}
		catch(SQLException s)
		{
			System.out.println(s);
		}

		result = sb.toString();
		//转换中文
		try
		{
			byte[] tmpbyte = result.getBytes("8859_1");
			result = new String(tmpbyte); 
			//把中文字符转换为Unicode吗
		    result = Unicode.stringToUnicode(result);
		}
		catch(UnsupportedEncodingException u)
		{
			System.out.println(u);
		}
		
		return result;		
	}

}