使用 QueryRunner 查询表中一条或多条记录

https://www.bilibili.com/video/BV1eJ411c7rf?p=52

BeanHandler

    @Test
    public void testQueryBean() {
        Connection conn = null;
        String sql = "select id, name, email, birth from customers where id = ?";

        /*
        AbstractKeyedHandler, AbstractListHandler, ArrayHandler, ArrayListHandler, BaseResultSetHandler,
        BeanHandler, BeanListHandler, BeanMapHandler, ColumnListHandler,
        KeyedHandler, MapHandler, MapListHandler, ScalarHandler
         */
        BeanHandler<Customer> rsh = new BeanHandler(Customer.class);
        Customer customer = null;

        try {
            QueryRunner runner = new QueryRunner();

            conn = JDBCUtils.getConnectionFromDruid();

            customer = runner.query(conn, sql, rsh, 9);

        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            JDBCUtils.closeResource(conn, null);
        }
        System.out.println(customer);
    }

Customer{id=9, name='蔡徐坤', email='caixukun@126.com', birth=1997-09-08}

BeanListHandler

/**
     * BeanListHandler:是 ResultSetHandler 接口的实现类，用于封装表中的多条记录构成的集合
     */
    @Test
    public void testQueryBeanList() {
        Connection conn = null;
        String sql = "select id, name, email, birth from customers where id < ?";

        /*
        AbstractKeyedHandler, AbstractListHandler, ArrayHandler, ArrayListHandler, BaseResultSetHandler,
        BeanHandler, BeanListHandler, BeanMapHandler, ColumnListHandler,
        KeyedHandler, MapHandler, MapListHandler, ScalarHandler
         */
        BeanListHandler<Customer> rsh = new BeanListHandler(Customer.class);
        List<Customer> list = null;
        QueryRunner runner = new QueryRunner();

        try {


            conn = JDBCUtils.getConnectionFromDruid();

            list = runner.query(conn, sql, rsh, 9);

        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            JDBCUtils.closeResource(conn, null);
        }

        list.forEach(System.out::println);
    }

Customer{id=2, name='李四', email='lisi@126.com', birth=2023-01-09}
Customer{id=3, name='章子怡', email='zzy@gmail.com', birth=2001-02-02}
Customer{id=4, name='刘攀', email='liupan@126.com', birth=1993-09-08}
Customer{id=5, name='张三丰', email='zhangsanfeng@126.com', birth=1992-09-08}
Customer{id=6, name='测试图片大于1M', email='xxxx@126.com', birth=1992-09-08}
Customer{id=7, name='测试图片大于1M', email='xxxx@126.com', birth=1992-09-08}

MapHandler

    /**
     * MapHandler:是 ResultSetHandler 接口的实现类，对应表中的一条记录
     * 将字段及相应字段的值作为 Map 中的 key 和 value
     */
    @Test
    public void testQueryMap() {
        Connection conn = null;
        String sql = "select id, name, email, birth from customers where id = ?";

        /*
        AbstractKeyedHandler, AbstractListHandler, ArrayHandler, ArrayListHandler, BaseResultSetHandler,
        BeanHandler, BeanListHandler, BeanMapHandler, ColumnListHandler,
        KeyedHandler, MapHandler, MapListHandler, ScalarHandler
         */
        MapHandler rsh = new MapHandler();
        Map<String, Object> map = new HashMap<>();
        QueryRunner runner = new QueryRunner();

        try {

            conn = JDBCUtils.getConnectionFromDruid();

            map = runner.query(conn, sql, rsh, 9);

        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            JDBCUtils.closeResource(conn, null);
        }

        map.forEach((k, v) -> System.out.printf("key:%s, value:%s\n", k, v));
    }

key:name, value:蔡徐坤
key:birth, value:1997-09-08
key:id, value:9
key:email, value:caixukun@126.com

MapListHandler

    /**
     * MapListHandler:是 ResultSetHandler 接口的实现类，对应表中的一条记录
     * 将字段及相应字段的值作为 Map 中的 key 和 value
     */
    @Test
    public void testQueryMapList() {
        Connection conn = null;
        String sql = "select id, name, email, birth from customers where id < ?";

        /*
        AbstractKeyedHandler, AbstractListHandler, ArrayHandler, ArrayListHandler, BaseResultSetHandler,
        BeanHandler, BeanListHandler, BeanMapHandler, ColumnListHandler,
        KeyedHandler, MapHandler, MapListHandler, ScalarHandler
         */
        MapListHandler rsh = new MapListHandler();
        List<Map<String, Object>> list = new ArrayList<>();
        QueryRunner runner = new QueryRunner();

        try {

            conn = JDBCUtils.getConnectionFromDruid();

            list = runner.query(conn, sql, rsh, 9);

        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            JDBCUtils.closeResource(conn, null);
        }

        list.forEach(System.out::println);

    }

{name=李四, birth=2023-01-09, id=2, email=lisi@126.com}
{name=章子怡, birth=2001-02-02, id=3, email=zzy@gmail.com}
{name=刘攀, birth=1993-09-08, id=4, email=liupan@126.com}
{name=张三丰, birth=1992-09-08, id=5, email=zhangsanfeng@126.com}
{name=测试图片大于1M, birth=1992-09-08, id=6, email=xxxx@126.com}
{name=测试图片大于1M, birth=1992-09-08, id=7, email=xxxx@126.com}

https://github.com/jihch/jdbc_2/blob/main/src/main/java/io/github/jihch/dbutils/QueryRunnerTest.java