c:foreach和c:if嵌套使用的问题

Question

原代码：

<c:forEach var="category" items="<%=c %>">
    price=${category.value.price  }  low=${low } high= ${high }

<div class="product-item bg-light">
    <div class="card">
        <div class="thumb-content">
            <!-- <div class="price">$200</div> -->
            <a href="./ListProduct?id=${category.value.ID} ">
                <img class="card-img-top img-fluid" src="${category.value.imageURL }" alt="Card image cap">
            </a>
        </div>
        <div class="card-body">
            <h4 class="card-title"><a href="./ListProduct?id=${category.value.ID}">${category.value.name }</a></h4>
            <ul class="list-inline product-meta">
                <li class="list-inline-item">
                    <a href=""><i class="fa fa-folder-open-o"></i>Electronics</a>
                </li>
                <li class="list-inline-item">
                    <a href=""><i class="fa fa-calendar"></i>26th December</a>
                </li>
            </ul>
            <p class="card-text">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Explicabo, aliquam!</p>
            <div class="product-ratings">
                <ul class="list-inline">
                    <li class="list-inline-item selected"><i class="fa fa-star"></i></li>
                    <li class="list-inline-item selected"><i class="fa fa-star"></i></li>
                    <li class="list-inline-item selected"><i class="fa fa-star"></i></li>
                    <li class="list-inline-item selected"><i class="fa fa-star"></i></li>
                    <li class="list-inline-item"><i class="fa fa-star"></i>价格：${category.value.price }</li>
                </ul>
            </div>
        </div>
    </div>
</div>




</c:forEach>

加入C：if标签后

<c:forEach var="category" items="<%=c %>">
    price=${category.value.price  }  low=${low } high= ${high }
**<c:if test="${1} ">**

<div class="product-item bg-light">
    <div class="card">
        <div class="thumb-content">
            <!-- <div class="price">$200</div> -->
            <a href="./ListProduct?id=${category.value.ID} ">
                <img class="card-img-top img-fluid" src="${category.value.imageURL }" alt="Card image cap">
            </a>
        </div>
        <div class="card-body">
            <h4 class="card-title"><a href="./ListProduct?id=${category.value.ID}">${category.value.name }</a></h4>
            <ul class="list-inline product-meta">
                <li class="list-inline-item">
                    <a href=""><i class="fa fa-folder-open-o"></i>Electronics</a>
                </li>
                <li class="list-inline-item">
                    <a href=""><i class="fa fa-calendar"></i>26th December</a>
                </li>
            </ul>
            <p class="card-text">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Explicabo, aliquam!</p>
            <div class="product-ratings">
                <ul class="list-inline">
                    <li class="list-inline-item selected"><i class="fa fa-star"></i></li>
                    <li class="list-inline-item selected"><i class="fa fa-star"></i></li>
                    <li class="list-inline-item selected"><i class="fa fa-star"></i></li>
                    <li class="list-inline-item selected"><i class="fa fa-star"></i></li>
                    <li class="list-inline-item"><i class="fa fa-star"></i>价格：${category.value.price }</li>
                </ul>
            </div>
        </div>
    </div>
</div>




**  </c:if>**
</c:forEach>  

使用c:foreach正常显示，但是加了c：if后显示不出来了，不管怎么写test语句
这是什么原因呢