FreeMarker 对null值的处理_JAVA_编程开发_程序员俱乐部

class="java" name="code">The FreeMarker template language doesn't know the Java language null at all. It doesn't have null keyword, and it can't test if something is null or not.

user.name?exists 
user.name?? 
Html代码  收藏代码
<#if user.name?exists>  
 //TO DO  
</#if>  
  
<#if user.age??>  
 //TO DO  
</#if>  

假设前提：user.name为null 
${user.name}，异常 
${user.name!},显示空白 
${user.name!'vakin'}，若user.name不为空则显示本身的值，否则显示vakin 
${user.name?default('vakin')}，同上 
${user.name???string(user.name,'vakin')},同上

<div class="grid_5 lable-right">
		     <label class="form-lbl">起始公里数(km)：</label>
			</div>
			<div class="grid_6">
				<input type="text" name="startNumberKm" id="startNumberKm" maxlength="10"
			      value="${outCar.startNumberKm!'${startNumberKmByLast}'}"  class="form-txt" />
			</div>
			<div class="grid_1"><em class="form-req">*</em></div>