Hibernate的Query接口的uniqueResult()方法（如果查询结果有多个值则抛出错误；结果有且只有一个值,返回一个object； 如果没值,返回
<div class="article_content">以前写代码，总免不了编写登陆部分。在获取user的时候，只可能返回一个user实例，或者为null。以前使用以下方法实现。
<div class="dp-highlighter bg_java"><ol class="dp-j"><li class="alt"><span><span class="keyword">public</span><span>?user?get(string?id){???</span></span></li><span>????session?session=hibernateutil.getsessionfactory().opensession();???</span><li class="alt"><span>????string?hql=<span class="string">"from?user?u?where?u.id?=??"</span><span>;???</span></span></li><span>????list?list=session.createquery(hql).setstring(<span class="number">0</span><span>,?id).list();???</span></span><li class="alt"><span>????<span class="keyword">if</span><span>?(list.size()==</span><span class="number">1</span><span>){???</span></span></li><span>????????<span class="keyword">return</span><span>?(user)list.get(</span><span class="number">0</span><span>);???</span></span><li class="alt"><span>????}<span class="keyword">else</span><span>{???</span></span></li><span>????????<span class="keyword">return</span><span>?</span><span class="keyword">null</span><span>;???</span></span><li class="alt"><span>????}???</span></li><span>}???</span></ol>