CRUD增删改查

preparedStatement的查询操作

 @Test
    public void statementTest() throws Exception{
        InputStream resourceAsStream = PreparedStatementTest.class.getClassLoader().getResourceAsStream("jdbc.properties");
        Properties properties = new Properties();
        properties.load(resourceAsStream);
        String url = properties.getProperty("url");
        String driver = properties.getProperty("driver");
        String user = properties.getProperty("user");
        String password = properties.getProperty("password");
        Class.forName(driver);
        Connection connection = DriverManager.getConnection(url, user, password);
        String sql = "select * from tb_city where id = ?";
        PreparedStatement preparedStatement = connection.prepareStatement(sql);
        preparedStatement.setInt(1,3);
        ResultSet resultSet = preparedStatement.executeQuery();
        while (resultSet.next()){
            int id = resultSet.getInt("id");
            String city_name = resultSet.getString("city_name");
            int country_id = resultSet.getInt("country_id");
            System.out.println("id:"+id+",city_name:"+city_name+",country_id:"+country_id);
        }
        resultSet.close();
        connection.close();
    }