goodslistbean.java

一个购物网站

package dataDisposal;

import java.io.*;
import java.sql.*;
import java.util.*;

public class GoodsListBean {
	private String dBDriver="sun.jdbc.odbc.JdbcOdbcDriver";
	private String connStr="jdbc:odbc:gamezone";
	private String user="";
	private String psw="";
	
	private Connection conn=null;
	private ResultSet rs=null;
	private	Statement stmt=null;
	private	ResultSetMetaData meta=null;	

	
	public GoodsListBean(){
		try{
			Class.forName(dBDriver);
		}
		catch(ClassNotFoundException exc){
			System.err.println("GoodsListBean():"+exc.getMessage());
		}
	}

	private Connection getConnection(){
		try{
			//连接数据库
			conn=DriverManager.getConnection(connStr);				
		}catch(Exception exc){
			System.out.println("getConn():"+exc.getMessage());	
		}
		return conn;		
	}
	/**
	 *参数：操作所需的SQL语句
	 *返回操作结果(用ArrayList)，如果操作失败，则返回null
	 */
	public ArrayList getList(String sql){	
		Hashtable rec=null;
		ArrayList fieldGetList=new ArrayList();

		int count,i;		
		try{
			try{
				conn=getConnection();
			}
			catch(Exception e){
				System.out.println("connection error");
				return null ;
			}
			if(conn==null)
				return null;
			stmt=conn.createStatement();
			rs=stmt.executeQuery(sql);
			meta=rs.getMetaData();
			count=meta.getColumnCount();
			
			while(rs.next()){   //注意:数据库中任何列都不能有空值,否则将会发生异常
				rec=new Hashtable();
				for(i=1;i<=count;i++){
					String name=meta.getColumnLabel(i);					
					rec.put(name,rs.getObject(name));
				}
				fieldGetList.add(rec);
			}	
			rs.close();
			rs=null;
			stmt.close();
			stmt=null;					
		}
		catch(Exception e){
			System.out.println("Exception here");
			System.out.println("getList(ds)::" );
			 e.printStackTrace();
		}
		finally{
			try {
				if (conn != null) {
					conn.close();
					conn = null;
				}
			}
			catch (Exception exc) {
				System.err.println("getList():"+exc.getMessage());	
			}	
		}
		return fieldGetList;
	}
	/**
	 *参数：操作所需的SQL语句
	 *返回操作结果(用Hashtable,只返回一条数据)，如果操作失败，则返回null
	 */	
	 
	public static void main(String args[]){
		GoodsListBean bean=new GoodsListBean();
		ArrayList list=null;
		list = bean.getList("select * from goodsInfo order by tradeTimes desc");
		System.out.println("size=" + list.size());
	}

	public Hashtable getHash(String sql){	
		Hashtable rec=new Hashtable();
		ResultSet rs=null;
		Statement stmt=null;
		Connection conn=null;
		ResultSetMetaData meta=null;
		int count,i;		
		try{
			conn=getConnection();
			stmt=conn.createStatement();
			rs=stmt.executeQuery(sql);
			meta=rs.getMetaData();
			count=meta.getColumnCount();
			if(rs.next()){
				for(i=1;i<=count;i++){
					String name=meta.getColumnLabel(i);					
					rec.put(name,rs.getObject(name));
				}				
			}	
			rs.close();
			rs=null;
			stmt.close();
			stmt=null;			
		}catch(Exception e){
			System.out.println("getHash()"+e.getMessage());
		}finally{
			try {
				if (conn != null) {
					conn.close();
					conn = null;
				}
			}
			catch (Exception exc) {
				System.out.println("getHash()"+exc.getMessage());	
			}	
		}
		return rec;
	}
	/**
	 *参数：进行更新的SQL语句
	 *根据SQL进行更新操作，如果操作成功，则返回true,否则返回false
	 */
	public boolean update(String sql){		
		boolean flag=false;	
		try{
			conn=getConnection();
			stmt=conn.createStatement();
			stmt.executeUpdate(sql);			
			stmt.close();
			stmt=null;	
			flag=true;		
		}catch(Exception e){
			System.out.println("getList()"+e.getMessage());
			flag=false;
		}
		finally{
			try {
				if (conn != null) {
					conn.close();
					conn = null;
				}
			} catch (Exception exc) {
				System.out.println("getHash()"+exc.getMessage());
			}	
		}
		return flag;
	}

		
	public void setUser(String user){
		this.user=user;
	}
	public String getUser(){
		return user;
	}
	
	public void setPsw(String psw){
		this.psw=psw;
	}
	
	public String getPsw(){
		return psw;
	}
	
	public void setDBDriver(String dBDriver){
		this.dBDriver=dBDriver;
	}
	public String getDBDriver(){
		return dBDriver;
	}
	
	public void setConnStr(String DBDriver){
		this.connStr=connStr;
	}
	public String getConnStr(){
		return connStr;
	}
}