dataconnection.java

一个用JSP编写的网站计数器

package com.webcount.database;
import java.sql.*;
import javax.sql.DataSource;
import javax.naming.*;

public class DataConnection {
	// 取得连接池中的连接
	public static Connection getFreeConnection(){
		Connection conn = null;
		try
		{
			Context initCtx=new InitialContext();
			// 通过JNDI取得连接池
			DataSource ds = (DataSource)initCtx.lookup("java:comp/env/jdbc/sqlserver");
			conn =ds.getConnection();
		}catch(Exception ex){
			ex.printStackTrace();
		}
		return conn;
	}
	// 取得PrepareStatement	
	public static PreparedStatement getPreparedStatement(Connection conn,String query){
		PreparedStatement pstmt = null;
		try{
			pstmt = conn.prepareStatement(query);
		}catch(Exception ex){
			ex.printStackTrace();
		}
		return pstmt;
	}
	
	// 执行PrepareStatement的DML操作
	public static boolean execute(PreparedStatement pstmt){
		boolean re = false;
		int number = 0;
		try{
			number = pstmt.executeUpdate();
			if(number>0){
				re = true;
			}
		}catch(Exception ex){
			ex.printStackTrace();
		}
		return re;
	}
	
	// 取得Statement
	public static Statement getStatement(Connection conn){
		Statement st = null;
		try{
			st = conn.createStatement();
		}catch(Exception ex){
			ex.printStackTrace();
		}
		return st;
	}
	
	//	取得通过Statement查询得到的ResultSet
	public static ResultSet getResult(Statement st,String query){
		ResultSet rs = null;
		try{
			rs = st.executeQuery(query);
		}catch(Exception ex){
			ex.printStackTrace();
		}
		return rs;
	}
	
	//	 取得通过PreparedStatement查询得到的ResultSet
	public static ResultSet getResult(PreparedStatement pstmt){
		ResultSet rs = null;
		try{
			rs = pstmt.executeQuery();
		}catch(Exception ex){
			ex.printStackTrace();
		}
		return rs;
	}
	
	//	 关闭ResultSet
	public static void closeResultSet(ResultSet rs){
		try{
			if(rs!=null){
				rs.close();
			}
		}catch(Exception ex){
			ex.printStackTrace();
		}
	}
	
	//	 关闭Statement
	public static void closeStatement(Statement st){
		try{
			if(st!=null){
				st.close();
			}
		}catch(Exception ex){
			ex.printStackTrace();
		}
	}
}