jdbc_从入门到精通_2

1.多条数据的select

封装在一个实体类中

    @Test
    public void test2()throws Exception{
        Connection connection = JDBCUtils.getConnection();
        String sql = "select * from user";
        PreparedStatement ps = connection.prepareStatement(sql);
        ResultSet rs = ps.executeQuery();
        List list = new ArrayList<>();
        while (rs.next()){
            int id = rs.getInt(1);
            String username = rs.getString(2);
            String password = rs.getString(3);
            String name = rs.getString(4);
            list.add(new User(id, username, password, name));

        }
        list.forEach(System.out::println);
        JDBCUtils.getClose(connection, ps, rs);
    }

2.连接池技术之c3p0技术

首先要导入包

    @Test
    public void test1()throws Exception{
        DataSource dataSource = new ComboPooledDataSource();
        Connection connection = dataSource.getConnection();
        System.out.println(connection);
    }

获取连接

3.连接池技术之德鲁伊

3.1 工厂模式创建

    @Test
    public void test2()throws Exception{
        Properties properties = new Properties();
        InputStream is = ClassLoader.getSystemClassLoader().getResourceAsStream("druid.properties");

        properties.load(is);
        DataSource dataSource = DruidDataSourceFactory.createDataSource(properties);
        Connection connection = dataSource.getConnection();
        System.out.println(connection);


    }

3.2 普通创建德鲁伊

    @Test
    public void test3()throws Exception{
        Properties properties = new Properties();
        InputStream is = ClassLoader.getSystemClassLoader().getResourceAsStream("druid.properties");

        properties.load(is);
        String username = properties.getProperty("username");
        String password = properties.getProperty("password");
        String url = properties.getProperty("url");
        String driverClassName = properties.getProperty("driverClassName");
        DruidDataSource ds = new DruidDataSource();
        ds.setDriverClassName(driverClassName);
        ds.setPassword(password);
        ds.setUsername(username);
        ds.setUrl(url);
        Connection connection = ds.getConnection();
        System.out.println(connection);
    }

4.连接池技术之DBCP

4.1 工厂创建模式

    @Test
    public void test5()throws Exception{
        InputStream is = ClassLoader.getSystemClassLoader().getResourceAsStream("dhcp.properties");
        Properties properties = new Properties();
        properties.load(is);

        DataSource dataSource = BasicDataSourceFactory.createDataSource(properties);
        Connection connection = dataSource.getConnection();
        System.out.println(connection);
    }

4.2 普通创建模式

    public void test4()throws Exception{
        BasicDataSource dataSource = new BasicDataSource();
        dataSource.setUrl("jdbc:mysql:///test");
        dataSource.setDriverClassName("com.mysql.jdbc.Driver");
        dataSource.setUsername("root");
        dataSource.setPassword("root");
        Connection connection = dataSource.getConnection();
        System.out.println(connection);
    }

5.DBUtils工具类

导入jar包

    @Test
    public void test2()throws Exception{
        DataSource dataSource = new ComboPooledDataSource();
        QueryRunner runner = new QueryRunner(dataSource);
        String sql = "select * from user where id = ?";
        User user = runner.query(sql, new BeanHandler(User.class), 1);
        System.out.println(user);

    }

发现DBUtils工具类只可以用c3p0数据源

   @Test
    public void test3()throws Exception{
        QueryRunner runner = new QueryRunner();
        Connection connection = JDBCUtils.getConnection();
        String sql = "update user set password = ? where id = ?";
        int update = runner.update(connection, sql, "1234", 1);
        System.out.println(update);
        JDBCUtils.getClose(connection, null);
    }