下圖爲一個普通的樹形菜單,這裏有幾個概念需要提前說明:
1、對於樹形菜單中的某一個菜單而言,都是有子節點與父節點的,根節點與無子節點的菜單除外
2、一個父節點是可以有多個子節點的,而一個子節點只能對應有一個父節點
下面直接上代碼:
數據庫腳本:
-- 建表代碼
create table t_hibernate_sys_tree_node
(
tree_node_id int primary key auto_increment, -- ID
tree_node_name varchar(50) not null, -- 名字
tree_node_type int not null check(tree_node_type = 1 or tree_node_type = 2), -- 節點類型:1 枝節點 2 葉節點
position int, -- 位置
parent_node_id int, -- 父節點ID
url varchar(1024), -- URL
foreign key(parent_node_id) references t_hibernate_sys_tree_node(tree_node_id)
);
-- 插入數據的代碼
insert into t_hibernate_sys_tree_node(tree_node_id, tree_node_name, tree_node_type, position, parent_node_id, url)
values(1,'系統管理',1, 1,null,null);
insert into t_hibernate_sys_tree_node(tree_node_id, tree_node_name, tree_node_type, position, parent_node_id, url)
values(2,'市場管理',1, 2,null,null);
insert into t_hibernate_sys_tree_node(tree_node_id, tree_node_name, tree_node_type, position, parent_node_id, url)
values(3,'字典管理',2, 3,1,null);
insert into t_hibernate_sys_tree_node(tree_node_id, tree_node_name, tree_node_type, position, parent_node_id, url)
values(4,'用戶管理',2, 4,1,null);
insert into t_hibernate_sys_tree_node(tree_node_id, tree_node_name, tree_node_type, position, parent_node_id, url)
values(5,'角色管理',2, 5,1,null);
insert into t_hibernate_sys_tree_node(tree_node_id, tree_node_name, tree_node_type, position, parent_node_id, url)
values(6,'權限管理',1, 6,1,null);
insert into t_hibernate_sys_tree_node(tree_node_id, tree_node_name, tree_node_type, position, parent_node_id, url)
values(7,'進貨管理',2, 7,2,null);
insert into t_hibernate_sys_tree_node(tree_node_id, tree_node_name, tree_node_type, position, parent_node_id, url)
values(8,'銷售管理',2, 8,2,null);
insert into t_hibernate_sys_tree_node(tree_node_id, tree_node_name, tree_node_type, position, parent_node_id, url)
values(9,'庫存管理',2, 9,2,null);
insert into t_hibernate_sys_tree_node(tree_node_id, tree_node_name, tree_node_type, position, parent_node_id, url)
values(10,'用戶分配角色',2, 10,6,null);
insert into t_hibernate_sys_tree_node(tree_node_id, tree_node_name, tree_node_type, position, parent_node_id, url)
values(11,'角色授予用戶',2, 11,6,null);
實體類:
package com.hibernate.entity;
import java.util.HashSet;
import java.util.Set;
public class TreeNode {
private Integer tree_node_id;
private String tree_node_name;
private Integer tree_node_type;
private Integer position;
private Integer parent_node_id;
private String url;
private TreeNode parent; //父節點
private Set<TreeNode> children=new HashSet<>(); //子節點
public Set<TreeNode> getTreeNodes() {
return children;
}
public void setTreeNodes(Set<TreeNode> children) {
this.children= children;
}
public TreeNode getTreeNode() {
return parent;
}
public void setTreeNode(TreeNode parent) {
this.parent= parent;
}
public Integer getTree_node_id() {
return tree_node_id;
}
public void setTree_node_id(Integer tree_node_id) {
this.tree_node_id = tree_node_id;
}
public String getTree_node_name() {
return tree_node_name;
}
public void setTree_node_name(String tree_node_name) {
this.tree_node_name = tree_node_name;
}
public Integer getTree_node_type() {
return tree_node_type;
}
public void setTree_node_type(Integer tree_node_type) {
this.tree_node_type = tree_node_type;
}
public Integer getPosition() {
return position;
}
public void setPosition(Integer position) {
this.position = position;
}
public Integer getParent_node_id() {
return parent_node_id;
}
public void setParent_node_id(Integer parent_node_id) {
this.parent_node_id = parent_node_id;
}
public String getUrl() {
return url;
}
public void setUrl(String url) {
this.url = url;
}
@Override
public String toString() {
return "TreeNode [tree_node_id=" + tree_node_id + ", tree_node_name=" + tree_node_name + ", tree_node_type="
+ tree_node_type + ", position=" + position + ", parent_node_id=" + parent_node_id + ", url=" + url
+ "]";
}
}
實體類的映射文件:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="com.hibernate.entity.TreeNode" table="t_hibernate_sys_tree_node">
<id name="tree_node_id" type="java.lang.Integer" column="tree_node_id">
<generator class="increment"></generator>
</id>
<property name="tree_node_name" type="java.lang.String" column="tree_node_name"></property>
<property name="tree_node_type" type="java.lang.Integer" column="tree_node_type"></property>
<property name="position" type="java.lang.Integer" column="position"></property>
<property name="parent_node_id" type="java.lang.Integer" column="parent_node_id"></property>
<property name="url" type="java.lang.String" column="url"></property>
<!-- 當前節點與父節點是多對一的關係 , name爲父節點的屬性名,class爲屬性的全限定名 , column爲對應的數據庫中的外鍵的列名(由於這裏是自關聯,所以爲與父節點有關聯的列) -->
<!-- 當column中的名字與實體映射文件中的其他的標籤的column有相同的時,則需要在其中一方加入insert="false" update="false" ,否則會報錯 -->
<many-to-one name="parent" class="com.hibernate.entity.TreeNode" column="parent_node_id" insert="false" update="false"></many-to-one>
<!-- 當前節點與子節點是一對多的關係 , name爲子節點的屬性名 -->
<set name="children">
<!-- column爲與子節點有關聯的列 -->
<key column="parent_node_id"></key>
<!-- 子節點的數據類型的全限定名 -->
<one-to-many class="com.hibernate.entity.TreeNode"></one-to-many>
</set>
</class>
</hibernate-mapping>
將實體的映射文件映射到hibernate的核心配置文件中去:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<!-- 配置數據源信息 -->
<property name="connection.username">root</property>
<property name="connection.password">123</property>
<property name="connection.url">jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=UTF-8&serverTimezone=GMT</property>
<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
<!-- 配置sql語句生成的規則,配置數據庫方言 -->
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>
<!-- 配置本地事務 -->
<property name="hibernate.current_session_context_class">thread</property>
<!-- 配置開發調試所用的配置show_sql,format_sql -->
<property name="show_sql">true</property>
<property name="format_sql">true</property>
<!-- 配置映射文件 -->
<mapping resource="com/hibernate/entity/TreeNode.hbm.xml"/>
</session-factory>
</hibernate-configuration>
編寫dao方法:
package com.hibernate.dao;
import org.hibernate.Hibernate;
import org.hibernate.Session;
import org.hibernate.Transaction;
import com.hibernate.entity.TreeNode;
import com.hibernate.util.HibernateUtils;
public class TreeNodeDao {
public TreeNode get(TreeNode treeNode) {
//HibernateUtils爲自己寫的工具類
Session session = HibernateUtils.getSession();
Transaction beginTransaction = session.beginTransaction();
TreeNode tree = session.get(TreeNode.class, treeNode.getTree_node_id());
/*
* 由於hibernate採用的是懶加載,下面三行代碼是將哪些內容設置爲立即加載
*/
Hibernate.initialize(tree);
Hibernate.initialize(tree.getTreeNode());
Hibernate.initialize(tree.getTreeNodes());
beginTransaction.commit();
session.close();
return tree;
}
}
使用junti或者main方法測試代碼:
package com.hibernate.dao;
import static org.junit.Assert.*;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import com.hibernate.entity.TreeNode;
public class TreeNodeDaoTest {
private TreeNodeDao treeNodeDao=new TreeNodeDao();
@Test
public void testGet() {
TreeNode treeNode=new TreeNode();
treeNode.setTree_node_id(6);
TreeNode node = treeNodeDao.get(treeNode);
System.out.println(node.getTreeNode().getTree_node_id()+" , "+node.getTreeNode().getTree_node_name());
System.out.println(node.getTree_node_id()+" , "+node.getTree_node_name());
System.out.println(node.getTreeNodes().size());
}
}
打印結果: