import java.io.IOException;

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.sql.Statement;

import java.util.Collection;

import java.util.Properties;

public class JDBC {

    private Properties p = new Properties();

    private static String driver;

    private static String url;

    private static String user;

    private static String psw;

    public static void main(String[] args) throws Exception {

        new JDBC().run();

    }

    void run() throws Exception{

        p.load(this.getClass().getResourceAsStream("properties"));//利用反射获取calss信息

        driver    =p.getProperty("driver"); //把获取信息赋值给变量

        url    =p.getProperty("url");     //把获取信息赋值给变量

user =p.getProperty("user");//把获取信息赋值给变量
 psw =p.getProperty("pwd"); //把获取信息赋值给变量
Class.forName(driver);
 Connection c ;
 c= DriverManager.getConnection(url,user,psw); 
Statement sta = c.createStatement();
 String sql = "select ename from emp"; 
ResultSet rs=sta.executeQuery(sql);
 while(rs.next()){
 System.out.println(rs.getString(1));
 }
 } 
}

Properties//配置文件 new File

driver=com.mysql.jdbc.Driver

url=jdbc:mysql://122.114.147.148:3306/java0613

user=java0613

pwd=java0613