dbconnection.java

比较好的BBS社区源码

package db;

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

public class DbConnection{
	Connection conn = null;
	Statement stmt = null;
	ResultSet rset = null;

	public DbConnection(){
	}

	/************************************************
	 * openConnection
	 * read file "db.txt"
	************************************************/
	public boolean openConnection(){
		Properties prop = new Properties();
		try{
			InputStream is = getClass().getResourceAsStream("db.txt");
			prop.load(is);
			if(is != null) is.close();
		}catch(IOException e){
			System.out.println("[DbConnection] Open db.txt File, Error!");
		}

		String jdbc = prop.getProperty("driver");
		String uri = prop.getProperty("url");

		//System.out.println("jdbc=[" + jdbc + "]");
		//System.out.println("uri=[" + uri + "]");

		try{
			Class.forName(jdbc).newInstance();
		}catch(ClassNotFoundException e){
			System.out.println("JDBC login, Error!@" + e.getMessage());
			return false;
		}catch (Exception e){
			System.err.println("Unable to load driver!");
                        e.printStackTrace();
                }

		try{
			this.conn = DriverManager.getConnection (uri);
		}catch(SQLException e){
			System.out.println("Generate Connection, Error!" + e.getMessage());
			return false;
		}
		return true;

	}


	/*************************************************
	 * executeQuery and executeUpdate
	 * query and update DB
	*************************************************/
	public ResultSet executeQuery(String query) throws SQLException{
		stmt = conn.createStatement();
		rset = stmt.executeQuery(query);
		return rset;
	}

	public void executeUpdate(String query) throws SQLException{
		stmt = conn.createStatement();
		stmt.executeUpdate(query);
		if(stmt != null) stmt.close();
	}

	public void close() throws SQLException{
		if(conn != null) conn.close();
		if(rset != null) rset.close();
		if(stmt != null) stmt.close();
	}

	protected void finalize() throws Throwable{
		close();
	}

	public static void main(String[] args){
		//Design for test purpose.
		DbConnection dc = new DbConnection();
		System.out.println(dc.openConnection());
	}

}