注意:需要一个Java类,一个dbinfo.properties配置文件
/*
    将连接数据库的信息配置到属性文件中，通过读取属性文件来获取连接数据库的信息
    这才是真正的开发，注意：不能将连接数据库的url user password写死到java程序中。
*/

**Test3**
-----

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

public class Test3
{
    public static void main(String[] args) throws Exception{

        //读取属性文件
        FileReader reader = new FileReader("dbinfo.properties");
        Properties pro  = new Properties();
        pro.load(reader);
        reader.close();

        //通过key获取value
        String driver = pro.getProperty("driver");
        String url = pro.getProperty("url");
        String user = pro.getProperty("user");
        String password = pro.getProperty("password");

        /*
        System.out.println(driver);
        System.out.println(url);
        System.out.println(user);
        System.out.println(password);
        */

        //JDBC
        Connection conn = null;
        Statement stmt = null;
        ResultSet rs = null;
        try{
            Class.forName(driver);
            conn = DriverManager.getConnection(url,user,password);
            stmt = conn.createStatement();
            String sql = "select deptno,dname,loc from dept"; 
            rs = stmt.executeQuery(sql);
            while(rs.next()){
                int deptno = rs.getInt("deptno");
                String dname = rs.getString("dname");
                String loc = rs.getString("loc");
                System.out.println(deptno + "," + dname + "," + loc);
            }
        }catch(SQLException e){
            e.printStackTrace();
        } finally{
            if(rs != null){
                try{
                    rs.close();
                }catch(SQLException e){
                    e.printStackTrace();
                }
            }
            if(stmt != null){
                try{
                    stmt.close();
                }catch(SQLException e){
                    e.printStackTrace();
                }
            }
            if(conn != null){
                try{
                    conn.close();
                }catch(SQLException e){
                    e.printStackTrace();
                }
            }
        }

    }
}

***dbinfo.properties**
----------------------

driver=com.mysql.jdbc.Driver
url=jdbc:mysql://192.168.132.12:3366/bjpowernode
user=root
password=123