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如果我們正在爲網站創建後端。我們顯然會創建類別和帖子/產品。要添加/編輯/刪除類別，我們顯然會創建一個類似於結構的表格。例如：This is category listing as table在springmvc中使用hibernate獲取子女人數
類別在同一個表中具有子類別，子類別的數量可以是1 - 許多。我想顯示上面圖片中提到的兒童類別的數量。
作爲CI開發商我用在視圖中使用查詢要做到這一點，
這裏是例子
<?php
if(sizeof($results)>0)
{
$i=1;
foreach($results as $key => $list)
{
if($i%2==0)$cls="row1"; else $cls="row2";
?>
<tr id="<?php echo $list->id;?>" class="<?php echo $cls; ?>">
<td> <?php echo $list->title, anchor("admin/categories/update/".$list->id."/", '<i class="fa fa-pencil rtrt"></i>'); ?></td>
<td>
<?php
// it will return number of childs
echo anchor ('admin/categories/category/'.$list->id, $this->Common->select_child ('tbl_category', $list->id));
?>
</td>
現在我使用Spring的MVC，休眠， Jpa和Mysql DB。我知道從一個jsp做sql查詢將是一個不好的習慣。
這是我的JSP代碼像結構表，
<table class="table table-striped">
<thead>
<tr>
<th><i class="fa fa-pencil"></i></th>
<th>Category Name</th>
<th>Child</th>
<th>Created</th>
<th>Updated</th>
<th><input type="checkbox" /></th>
</tr>
</thead>
<tbody>
<c:if test="${not empty category}">
<c:forEach var="cat" items="${category}">
<tr>
<td><a href="${pageContext.request.contextPath}/category/${cat.id}/edit"><i class="fa fa-pencil"></i></a></td>
<td>${cat.title}</td>
<td><a href="${pageContext.request.contextPath}/category/show/${cat.id}"><i class="fa fa-folder-open"></i></a></td>
<td>${cat.created}</td>
<td>${cat.updated}</td>
<td><input type="checkbox" /></td>
</tr>
</c:forEach>
</c:if>
這裏是類POJO類
@Entity
@Table(name = "categories")
public class Categories {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "id")
private Long id;
private Long parent_id;
private String title;
private String url_title;
private String description;
private String created;
private String updated;
/*
* @ At the time of Creating new user
* Auto persist created date
* Auto persist updated for first time
*/
@PrePersist
protected void onCreate(){
// Date conversion to string
Date date = new Date();
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd h:mm:s");
sdf.setLenient(false);
String now = sdf.format(date);
created = now;
updated = now;
}
/*
* Respective Getter and Setter Methods
*
*/
public Long getId() {
return id;
}public void setId(Long id) {
this.id = id;
}
public Long getParent_id() {
return parent_id;
}public void setParent_id(Long parent_id) {
this.parent_id = parent_id;
}
public String getTitle() {
return title;
}public void setTitle(String title) {
this.title = title;
}
public String getUrl_title() {
return url_title;
}public void setUrl_title(String url_title) {
this.url_title = url_title;
}
public String getCreated() {
return created;
}public void setCreated(String created) {
this.created = created;
}
public String getUpdated() {
return updated;
}public void setUpdated(String updated) {
this.updated = updated;
}
public String getDescription() {
return description;
}public void setDescription(String description) {
this.description = description;
}
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
Categories other = (Categories) obj;
if (id == null) {
if (other.id != null)
return false;
} else if (!id.equals(other.id))
return false;
return true;
}
問題是
我怎樣才能讓孩子數不從Jsp做sql查詢？ 請幫助我，我需要一個建議。
你能添加categorie實體pleaz嗎？ –
我剛添加了類別類？你可以請建議我，如何實現我所需要的。 –
我v發佈了一個答案，但我不知道你真正的意思是：**兒童數量** –