首页 > 代码库 > jdbc,采用properties文件保存数据库账号密码以及链接

jdbc,采用properties文件保存数据库账号密码以及链接

1,在根目录创建 mysql.properties 文件,使用这个文件是为了方便以后生成class文件后可修改链接任意数据库

技术分享

 

2,导入jar包,自行百度下载。

 

3,写一个 SqlUtil.class (Sql工具类)

package com.sogood.util;import java.io.IOException;import java.sql.*;import java.util.Properties;public class SqlUtil {    private static String username;    private static String password;    private static String url;    static {        Properties pps = new Properties();        try {            pps.load(SqlUtil.class.getResourceAsStream("/com/sogood/mysql.properties"));            username = pps.getProperty("username");            password = pps.getProperty("password");            url = pps.getProperty("url");        } catch (IOException e) {            e.printStackTrace();        }    }    public static Connection getConnection() {        Connection con = null;        try {            Class.forName("com.mysql.jdbc.Driver");            con = DriverManager.getConnection(url, username, password);// 创建数据连接        } catch (SQLException e) {            e.printStackTrace();            System.out.println("数据库连接失败");        } catch (ClassNotFoundException e) {            throw new RuntimeException("驱动类找不到");        }        return con;    }    public static void close(Connection con, Statement stm, ResultSet rs) {        if (rs != null) {            try {                rs.close();            } catch (SQLException e) {                e.printStackTrace();            }        }        if (stm != null) {            try {                stm.close();            } catch (SQLException e) {                e.printStackTrace();            }        }        if (con != null) {            try {                con.close();            } catch (SQLException e) {                e.printStackTrace();            }        }    }}

 

4,写一个Demo.class 类测试一下

 1 package com.sogood.jdbc; 2  3 import com.sogood.util.SqlUtil; 4  5 import java.sql.Connection; 6 import java.sql.ResultSet; 7 import java.sql.SQLException; 8 import java.sql.Statement; 9 10 public class Demo {11     public static void main(String[] args) throws SQLException {12         query();13     }14 15     private static void query() {16         Connection con = null;17         Statement stm = null;18         ResultSet rs = null;19         try {20             con = SqlUtil.getConnection();21             String sql = "SELECT * FROM STUDENT";22             stm = con.createStatement();23             rs = stm.executeQuery(sql);24             System.out.println("查询结果:");25             while (rs.next()) {26                 int id = rs.getInt("id");27                 System.out.println("id = " + id);28             }29         } catch (Exception e) {30             e.printStackTrace();31         } finally {32             SqlUtil.close(con, stm, rs);33         }34     }35 }

 

jdbc,采用properties文件保存数据库账号密码以及链接