public static Db use() {
		return use(DSFactory.get());
	}
@Test
	public void pageTest() throws SQLException {
		// 测试数据库中一共4条数据，第0页有3条，第1页有1条
		List<Entity> page0 = Db.use().page(Entity.create("user"), 0, 3);
		assertEquals(3, page0.size());
		List<Entity> page1 = Db.use().page(Entity.create("user"), 1, 3);
		assertEquals(1, page1.size());
	}