列表中的记录上下移动

 最近有一个需求是实现一个表格中记录的上下移动如下图所示

选择其中一项，点击上下移动则则可以对记录上下移动。

这个项目使用的是jsf+hibernate+spring实现的

liteBean中的内容：

/**
	 * 上移一条记录
	 */
	@Action(id = "up", event = "onclick")
	public void up() {
		Object[] objs = grid.getSelectedValues();
		if (objs == null || objs.length == 0) {
			Browser.execClientScript("window.alert('请选择一条记录！');");
			return;
		}
		selectedRowData = objs[0];
		DictionaryItem dicItem = (DictionaryItem) selectedRowData;
		if (null != dictionaryItemService.upExchange(dicItem)) {
			Browser.alert("第一条不能再上移");
		}
		reload();
	}

	/**
	 * 下移一条记录
	 */
	@Action(id = "down", event = "onclick")
	public void down() {
		Object[] objs = grid.getSelectedValues();
		if (objs == null || objs.length == 0) {
			Browser.execClientScript("window.alert('请选择一条记录！');");
			return;
		}
		selectedRowData = objs[0];
		DictionaryItem dicItem = (DictionaryItem) selectedRowData;
		if (null != dictionaryItemService.downExchange(dicItem)) {
			Browser.alert("最后一条不能再下移");
		}
		reload();
	}

 在service层得代码：

@Override
	public String upExchange(DictionaryItem dicItem) {

		long order = dicItem.getOrder();
		DictionaryItem nextDicItem = dictionaryItemDao.nextItem(order);
		if(nextDicItem!=null){
			long nextOrder = nextDicItem.getOrder();

			long number = order;
			order = nextOrder;
			nextOrder = number;
			
			dicItem.setOrder(order);
			nextDicItem.setOrder(nextOrder);
			
			modify(dicItem);
			modify(nextDicItem);
			
			return null;
		}
		return EXCHANG_ERROR;
	}

	@Override
	public String downExchange(DictionaryItem dicItem) {
		long order = dicItem.getOrder();
		DictionaryItem preDicItem = dictionaryItemDao.preItem(order);
		if(preDicItem!=null){
			long nextOrder = preDicItem.getOrder();

			long number = order;
			order = nextOrder;
			nextOrder = number;
			
			dicItem.setOrder(order);
			preDicItem.setOrder(nextOrder);
			
			modify(dicItem);
			modify(preDicItem);
			
			return null;
		}
		return EXCHANG_ERROR;
	}

dao层得代码

@Override
	public DictionaryItem nextItem(long order) {
		
		final long nextOrder = order;
		final String sql = "from DictionaryItem dictionaryItem where dictionaryItem.order>? order by dictionaryItem.order asc";

		return (DictionaryItem) this.getHibernateTemplate().execute(
				new HibernateCallback() {
					@Override
					public DictionaryItem doInHibernate(Session session)
							throws HibernateException, SQLException {
						DictionaryItem obj = (DictionaryItem) session
								.createQuery(sql).setLong(0, nextOrder)
								.setMaxResults(1).uniqueResult();

						return obj;
					}
				});
	}

	@Override
	public DictionaryItem preItem(long order) {
		
		final long preOrder = order;
		final String sql = "from DictionaryItem dictionaryItem where dictionaryItem.order<? order by dictionaryItem.order desc";

		return (DictionaryItem) this.getHibernateTemplate().execute(
				new HibernateCallback() {
					@Override
					public DictionaryItem doInHibernate(Session session)
							throws HibernateException, SQLException {
						DictionaryItem obj = (DictionaryItem) session
								.createQuery(sql).setLong(0, preOrder)
								.setMaxResults(1).uniqueResult();
						return obj;
					}
				});
	}