下图为一个普通的树形菜单,这里有几个概念需要提前说明:
1、对于树形菜单中的某一个菜单而言,都是有子节点与父节点的,根节点与无子节点的菜单除外
2、一个父节点是可以有多个子节点的,而一个子节点只能对应有一个父节点
下面直接上代码:
数据库脚本:
-- 建表代码
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), -- 节点类型:1 枝节点 2 叶节点
position int, -- 位置
parent_node_id int, -- 父节点ID
url varchar(1024), -- URL
foreign key(parent_node_id) references t_hibernate_sys_tree_node(tree_node_id)
);
-- 插入数据的代码
insert into t_hibernate_sys_tree_node(tree_node_id, tree_node_name, tree_node_type, position, parent_node_id, url)
values(1,'系统管理',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,'市场管理',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,'用户管理',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,'权限管理',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,'进货管理',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,'销售管理',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,'库存管理',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,'用户分配角色',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,'角色授予用户',2, 11,6,null);
实体类:
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; //父节点
private Set<TreeNode> children=new HashSet<>(); //子节点
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
+ "]";
}
}
实体类的映射文件:
<?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>
<!-- 当前节点与父节点是多对一的关系 , name为父节点的属性名,class为属性的全限定名 , column为对应的数据库中的外键的列名(由于这里是自关联,所以为与父节点有关联的列) -->
<!-- 当column中的名字与实体映射文件中的其他的标签的column有相同的时,则需要在其中一方加入insert="false" update="false" ,否则会报错 -->
<many-to-one name="parent" class="com.hibernate.entity.TreeNode" column="parent_node_id" insert="false" update="false"></many-to-one>
<!-- 当前节点与子节点是一对多的关系 , name为子节点的属性名 -->
<set name="children">
<!-- column为与子节点有关联的列 -->
<key column="parent_node_id"></key>
<!-- 子节点的数据类型的全限定名 -->
<one-to-many class="com.hibernate.entity.TreeNode"></one-to-many>
</set>
</class>
</hibernate-mapping>
将实体的映射文件映射到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>
<!-- 配置数据源信息 -->
<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语句生成的规则,配置数据库方言 -->
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>
<!-- 配置本地事务 -->
<property name="hibernate.current_session_context_class">thread</property>
<!-- 配置开发调试所用的配置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>
编写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为自己写的工具类
Session session = HibernateUtils.getSession();
Transaction beginTransaction = session.beginTransaction();
TreeNode tree = session.get(TreeNode.class, treeNode.getTree_node_id());
/*
* 由于hibernate采用的是懒加载,下面三行代码是将哪些内容设置为立即加载
*/
Hibernate.initialize(tree);
Hibernate.initialize(tree.getTreeNode());
Hibernate.initialize(tree.getTreeNodes());
beginTransaction.commit();
session.close();
return tree;
}
}
使用junti或者main方法测试代码:
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());
}
}
打印结果: