Java—JBDC（通过properties配置文件链接数据库）

public class JBDC_V1 {
    private static String driver;
    private static String url;
    private static String username;
    private static String password;
/**
 * 静态代码块加载配置文件信息
 */

    static {
        try{
           ResourceBundle bundle = ResourceBundle.getBundle("db");
           driver = bundle.getString("driver");
           url = bundle.getString("url");
           username = bundle.getString("username");
           password = bundle.getString("password");
        }catch (Exception e){
            e.printStackTrace();
        }
    }

    public static Connection getConnection() {
        Connection conn = null;
        try {
            Class.forName(driver);
            conn = DriverManager.getConnection(url, username, password);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return conn;
    }


    public static void release(Connection conn, PreparedStatement pstmt, ResultSet rs) {
        if (rs != null) {
            try {
                rs.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        if (pstmt != null) {
            try {
                pstmt.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        if (conn != null) {
            try {
                conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }

    }
}

---

public class JBDC_V2 {
    private static String driver;
    private static String url;
    private static String username;
    private static String password;

    /**
     * 静态代码块加载配置文件信息
     */
    static {
        try {
            // 1.通过当前类获取类加载器
            ClassLoader classLoader = JBDC_V2.class.getClassLoader();
            // 2.通过类加载器的方法获得一个输入流
            InputStream is = classLoader.getResourceAsStream("db.properties");
            // 3.创建一个properties对象
            Properties props = new Properties();
            // 4.加载输入流
            props.load(is);
            // 5.获取相关参数的值
            driver = props.getProperty("driver");
            url = props.getProperty("url");
            username = props.getProperty("username");
            password = props.getProperty("password");
        } catch (IOException e) {
            e.printStackTrace();
        }

    }

    /**
     * 获取连接方法
     *
     * @return
     */
    public static Connection getConnection() {
        Connection conn = null;
        try {
            Class.forName(driver);
            conn = DriverManager.getConnection(url, username, password);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return conn;
    }

    public static void release(Connection conn, PreparedStatement pstmt, ResultSet rs) {
        if (rs != null) {
            try {
                rs.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        if (pstmt != null) {
            try {
                pstmt.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        if (conn != null) {
            try {
                conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}

---

配置文件（放置src目录）

driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/db1?useUnicode=true&characterEncoding=utf8
username=root
password=

---

检测类

public class JBDC_Test {

    @Test
public void test2() {
        Connection conn = null;
PreparedStatement pstmt = null;
        try {
            // 1.获取连接
conn = JBDC_V2.getConnection();
// 2.编写sql语句
String sql = "insert t1 (id,name) value (?,?)";
// 3.获取执行sql语句对象
pstmt = conn.prepareStatement(sql);
// 4.设置参数
pstmt.setInt(1, 5);
pstmt.setString(2, "xjj");
// 5.执行删除操作
int row = pstmt.executeUpdate();
            if (row > 0) {
                System.out.println("删除成功!");
} else {
                System.out.println("删除失败!");
}
        } catch (Exception e) {
             throw new RuntimeException(e);
} finally {
            // 6.释放资源
JBDC_V2.release(conn, pstmt, null);
}
    }

public class JBDC_V2 {
    private static String driver;
    private static String url;
    private static String username;
    private static String password;

/**
     * 静态代码块加载配置文件信息
     */
static {
        try {
            // 1.通过当前类获取类加载器
ClassLoader classLoader = JBDC_V2.class.getClassLoader();
// 2.通过类加载器的方法获得一个输入流
InputStream is = classLoader.getResourceAsStream("db.properties");
// 3.创建一个properties对象
Properties props = new Properties();
// 4.加载输入流
props.load(is);
// 5.获取相关参数的值
driver = props.getProperty("driver");
url = props.getProperty("url");
username = props.getProperty("username");
password = props.getProperty("password");
} catch (IOException e) {
            e.printStackTrace();
}

    }

    /**
     * 获取连接方法
     *
     * @return
*/
public static Connection getConnection() {
        Connection conn = null;
        try {
            Class.forName(driver);
conn = DriverManager.getConnection(url, username, password);
} catch (Exception e) {
            e.printStackTrace();
}
        return conn;
}

    public static void release(Connection conn, PreparedStatement pstmt, ResultSet rs) {
        if (rs != null) {
            try {
                rs.close();
} catch (SQLException e) {
                e.printStackTrace();
}
        }
        if (pstmt != null) {
            try {
                pstmt.close();
} catch (SQLException e) {
                e.printStackTrace();
}
        }
        if (conn != null) {
            try {
                conn.close();
} catch (SQLException e) {
                e.printStackTrace();
}
        }

    }
}