从配置文件里读取数据，实现多数据库连接

配置文件:

db.properties

 driverClass=com.mysql.jdbc.Driver
 url=jdbc:mysql://127.0.0.1/itbbs
 username=root
 password=sa

加载配置文件:

 package com.ccl.db;

 import java.io.IOException;
 import java.io.InputStream;
 import java.util.InvalidPropertiesFormatException;
 import java.util.Properties;

 public class LoadConfig {

     /**
      * @author chengchanglun
      * @param args
      */

     private Properties prop;

     /**
      * @param path
      *            as "/db.properties"
      */
     public LoadConfig(String path) {

         prop = new Properties();

         InputStream in = null;

         try {

             in = getClass().getResourceAsStream(path);

             prop.load(in);

             in.close();

         } catch (IOException e) {

             e.printStackTrace();
         }

     }

     public String getDriverClass() {

         return prop.getProperty("driverClass");

     }

     public String getURL() {

         return prop.getProperty("url");

     }

     public String getUserName() {

         return prop.getProperty("username");
     }

     public String getPassWord() {

         return prop.getProperty("password");
     }

     public static void main(String args[]) {

         LoadConfig c = new LoadConfig("/db.properties");

         Properties p = new Properties();

     }

 }

连接数据库:

 package com.ccl.db;

 import java.sql.Connection;
 import java.sql.DriverManager;

 /**
  * @author chengchanglun
  * @category db
  */
 public class ConnectionDataBase {

     private static LoadConfig config;

     private static Connection conn = null;

     public ConnectionDataBase() {

         init();

     }

     public static void init() {

         config = new LoadConfig("/db.properties");

     }

     public ConnectionDataBase(String path) {

         config = new LoadConfig(path);

     }

     public static Connection getConnection() {

         init();

         try {

             Class.forName(config.getDriverClass());

             conn = DriverManager.getConnection(config.getURL(),
                     config.getUserName(), config.getPassWord());

         } catch (Exception e) {

             System.out.println(e.getMessage());
         }

         return conn;

     }

     public static void main(String[] args) {

         Connection c = ConnectionDataBase.getConnection();

         System.out.println(c);

     }

 }