java中读取配置文件的方法和数据库底层的编写

最近在做一个OA(办公自动化)系统，看到别人写的关于读取配置文件的代码：




/**//*


* Created on 2005-11-6


*


* TODO To change the template for this generated file go to


* Window - Preferences - Java - Code Style - Code Templates


*/


package com.mycompany.database;




import java.sql.Connection;


import java.sql.DriverManager;


import java.sql.SQLException;


import java.util.Enumeration;


import java.util.Hashtable;


import java.util.PropertyResourceBundle;




import javax.naming.Context;


import javax.naming.InitialContext;


import javax.naming.NamingException;


import javax.sql.DataSource;






/** *//**


* @author Administrator


*


* TODO To change the template for this generated type comment go to Window -


* Preferences - Java - Code Style - Code Templates


*/




public class Database ...{




/** *//**


* 数据库访问URL


*/


private static String url;






/** *//**


* 数据库驱动


*/


private static String driver;






/** *//**


* 数据库访问用户名


*/


private static String username;






/** *//**


* 数据库访问口令


*/


private static String password;






/** *//**


* 访问类型


*/


private static String type;






/** *//**


* 数据源名称


*/


private static String datasource;






/** *//**


* 配置文件名称


*/


private final static String fileName = "database";




private static ThreadLocal connection = new ThreadLocal();






static ...{


config();


}






private static void config() ...{


//读取系统配置


PropertyResourceBundle resourceBundle = (PropertyResourceBundle) PropertyResourceBundle


.getBundle(fileName);


//将系统设置赋值给类变量


Enumeration enu = resourceBundle.getKeys();




while (enu.hasMoreElements()) ...{


String propertyName = enu.nextElement().toString();


if (propertyName.equals("database.url"))


url = resourceBundle.getString("database.url");


if (propertyName.equals("database.driver"))


driver = resourceBundle.getString("database.driver");


if (propertyName.equals("database.username"))


username = resourceBundle.getString("database.username");


if (propertyName.equals("database.password"))


password = resourceBundle.getString("database.password");


if (propertyName.equals("database.type"))


type = resourceBundle.getString("database.type");


if (propertyName.equals("database.datasource"))


datasource = resourceBundle.getString("database.datasource");


}




}






/** *//**


* 取得数据库连接


* @return


* @throws SQLException


*/


public synchronized static java.sql.Connection getConnection()




throws SQLException ...{


Connection con = (Connection) connection.get();




if (con != null && !con.isClosed()) ...{


return con;


}




if ("pooled".equalsIgnoreCase(type)) ...{


//从JNDI中取得数据源




try ...{


//此处对于不同的应用服务器，对env传入不同


Hashtable env = new Hashtable();


//此处对于不同的应用服务器，对env传入不同


Context ctx = new InitialContext(env); // 从命名系统中获取 DataSource 工厂对象


DataSource dataSource = (DataSource) ctx.lookup(datasource);


con= dataSource.getConnection();


connection.set(con);


return con;




} catch (NamingException e) ...{


e.printStackTrace();


}




} else ...{


//直接使用JDBC驱动连接




try ...{


Class providerClass = Class.forName(driver);


con = DriverManager.getConnection(url, username,


password);


con.setAutoCommit(false);


connection.set(con);


return con;






} catch (ClassNotFoundException e) ...{


e.printStackTrace();


}


}


return null;


}






public static void commit() ...{


Connection con = (Connection) connection.get();




try ...{


con.commit();




} catch (SQLException e) ...{


e.printStackTrace();


}


}






public static void rollback() ...{


Connection con = (Connection) connection.get();




try ...{


con.rollback();




} catch (SQLException e) ...{


e.printStackTrace();


}


}






public synchronized static void releaseConnection(Connection connection) ...{






try ...{


if (connection != null && !connection.isClosed())


connection.close();




} catch (SQLException e) ...{


// TODO Auto-generated catch block


e.printStackTrace();


}


connection = null;


}




public static void main(String[] args) ...{






try ...{


Database.getConnection();




} catch (SQLException e) ...{


// TODO Auto-generated catch block


e.printStackTrace();


}


}


}

其中数据库配置文件为database.propertes，放置在与包位置平行的文件夹下：

database.driver=com.mysql.jdbc.Driver
database.url=jdbc:mysql://localhost/news?user=root&password=123456&useUnicode=true&characterEncoding=gbk