Hibernate注解实现单表递归树形结构
目录：
- 概述
- 环境
- 代码示例测试结果
[一]、概述
在系统中，经常会用到无限级递归的树形结构，比如菜单、组织机构管理、多级分类等等，一般是在同一个表中定义父子关系实现这种树形结构，本文主要讲述如何运用hibernate全注解的方式实现这个功能。
[二]、环境
- hibernate 4.1.2
- java 1.6
- mysql 5.1
[三]、代码示例
第一步：创建Entity类，并添加注解实现关联关系
ps: 主要是利用@ManyToOne 和 @OneToMany 配置在同一个Entity类中实现树形递归的结构。
TreeNode.java
package com.micmiu.hibernate.anno.entity;
import java.util.LinkedHashSet;
import java.util.Set;
import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.OneToMany;
import javax.persistence.Table;
/**
* 树形结构示例
*
* @author <a href="http://www.micmiu.com">Michael Sun</a>
*/
@Entity
@Table(name = "DEMO_T_TREE_NODE")
public class TreeNode {
public TreeNode() {
}
public TreeNode(String name) {
this.name = name;
}
private int id;
private String name;
// 父节点
private TreeNode parent;
// 子节点
private Set<TreeNode> children = new LinkedHashSet<TreeNode>();
@Id
@Column(name = "ID")
@GeneratedValue
public int getId() {
return id;
}
@Column(name = "NAME", length = 20)
public String getName() {
return name;
}
@ManyToOne(cascade = CascadeType.ALL, fetch = FetchType.EAGER)
@JoinColumn(name = "PARENT_ID")
public TreeNode getParent() {
return parent;
}
@OneToMany(cascade = CascadeType.ALL, mappedBy = "parent", fetch = FetchType.EAGER)
public Set<TreeNode> getChildren() {
return children;
}
public void setId(int id) {
this.id = id;
}
public void setName(String name) {
this.name = name;
}
public void setParent(TreeNode parent) {
this.parent = parent;
}
public void setChildren(Set<TreeNode> children) {
this.children = children;
}
}
第二步：创建hibernate默认配置文件：
hibernate.cfg.xml
<?xml version='1.0' encoding='UTF-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>
<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="connection.url">jdbc:mysql://localhost:3306/michaeldemo</property>
<property name="connection.username">root</property>
<property name="connection.password"></property>
<property name="show_sql">true</property>
<property name="format_sql">true</property>
<property name="current_session_context_class">thread</property>
<property name="hbm2ddl.auto">update</property>
<mapping class="com.micmiu.hibernate.anno.entity.TreeNode" />
</session-factory>
</hibernate-configuration>
第三步：创建测试文件：
HibernateAnnoTreeTest.java
package com.micmiu.hibernate;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
import org.hibernate.service.ServiceRegistry;
import org.hibernate.service.ServiceRegistryBuilder;
import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.Test;
import com.micmiu.hibernate.anno.entity.TreeNode;
/**
* 测试
*
* @author <a href="http://www.micmiu.com">Michael Sun</a>
*/
public class HibernateAnnoTreeTest {
private static SessionFactory sessionFactory;
@BeforeClass
public static void beforeClass() {
Configuration configuration = new Configuration().configure();
ServiceRegistry serviceRegistry = new ServiceRegistryBuilder()
.applySettings(configuration.getProperties())
.buildServiceRegistry();
sessionFactory = configuration.buildSessionFactory(serviceRegistry);
}
@AfterClass
public static void afterClass() {
sessionFactory.close();
}
@Test
public void testTreeCRUD() {
// 先运行添加测试
// testSave();
// 读取测试
// testRead();
// 更新测试
testUpdate();
// 删除测试
// testDelete();
}
public void testSave() {
System.out.println("========>测试添加 start <========");
Session session = sessionFactory.openSession();
session.beginTransaction();
TreeNode rootNode = initData();
session.save(rootNode);
session.getTransaction().commit();
session.close();
System.out.println("========>测试添加 end <========");
// 读取添加的数据
testRead();
}
public void testRead() {
System.out.println("========>读取 start <========");
Session session = sessionFactory.openSession();
session.beginTransaction();
System.out.println("-----> get root node:");
TreeNode rootNode = (TreeNode) session.get(TreeNode.class, 1);
System.out.println("-----> 输出树形结构如下:");
printNode(rootNode, 0);
session.getTransaction().commit();
session.close();
System.out.println("========>读取 end <========");
}
public void testUpdate() {
// 更新前读取信息
testRead();
System.out.println("========>测试更新 start <========");
Session session = sessionFactory.openSession();
session.beginTransaction();
System.out.println("---> 更新节点属性");
TreeNode rootNode = (TreeNode) session.get(TreeNode.class, 1);
System.out.println("get root node:" + rootNode.getName()
+ " child size:" + rootNode.getChildren().size());
rootNode.setName(rootNode.getName() + "(我的blog)");
TreeNode node_del = null;
for (TreeNode node : rootNode.getChildren()) {
if ("Hazel".equals(node.getName())) {
node_del = node;
}
}
System.out.println("---> 删除节点(包含子节点)");
System.out.println("delete node:" + node_del.getName() + " child size:"
+ node_del.getChildren().size());
node_del.setParent(null);
rootNode.getChildren().remove(node_del);
session.delete(node_del);
System.out.println("---> 添加节点(包含子节点)");
TreeNode node_add = new TreeNode("企业应用");
node_add.setParent(rootNode);
rootNode.getChildren().add(node_add);
TreeNode node_add_0 = new TreeNode("SNMP");
node_add_0.setParent(node_add);
node_add.getChildren().add(node_add_0);
TreeNode node_add_1 = new TreeNode("SSO");
node_add_1.setParent(node_add);
node_add.getChildren().add(node_add_1);
session.update(rootNode);
System.out.println("---> 节点下添加子节点");
TreeNode node_update = (TreeNode) session.get(TreeNode.class, 6);
TreeNode node_child_add = new TreeNode("go(新增)");
System.out.println("append child node:" + node_child_add.getName()
+ " to parent node: " + node_update.getName());
node_child_add.setParent(node_update);
node_update.getChildren().add(node_child_add);
System.out.println("---> 节点下删除子节点");
TreeNode node_child_del = node_update.getChildren().iterator().next();
System.out.println("delete node child :" + node_child_del.getName()
+ " from parent node: " + node_update.getName());
node_update.getChildren().remove(node_child_del);
node_child_del.setParent(null);
session.delete(node_child_del);
session.update(node_update);
session.getTransaction().commit();
session.close();
System.out.println("========>测试更新 end <========");
// 更新后读取信息
testRead();
}
public void testDelete() {
// 删除前读取信息
testRead();
System.out.println("========>测试删除 start <========");
Session session = sessionFactory.openSession();
session.beginTransaction();
TreeNode node = (TreeNode) session.get(TreeNode.class, 6);
System.out.println("node:" + node.getName() + " child size:"
+ node.getChildren().size());
TreeNode childNode = node.getChildren().iterator().next();
childNode.setParent(null);
node.getChildren().remove(childNode);
session.delete(childNode);
System.out.println("delete node:" + childNode.getName()
+ " from parent:" + node.getName());
session.update(node);
session.getTransaction().commit();
session.close();
System.out.println("========>测试删除 end <========");
// 删除后读取信息
testRead();
}
/**
* 模拟测试数据
*/
private TreeNode initData() {
TreeNode rootNode = new TreeNode("micmiu.com");
// 一级
TreeNode node0 = new TreeNode("Michael");
node0.setParent(rootNode);
rootNode.getChildren().add(node0);
// 二级
TreeNode node0_0 = new TreeNode("J2EE");
node0_0.setParent(node0);
node0.getChildren().add(node0_0);
// 二级
TreeNode node0_1 = new TreeNode("SOA");
node0_1.setParent(node0);
node0.getChildren().add(node0_1);
// 二级
TreeNode node0_2 = new TreeNode("NoSQL");
node0_2.setParent(node0);
node0.getChildren().add(node0_2);
// 二级
TreeNode node0_3 = new TreeNode("编程语言");
node0_3.setParent(node0);
node0.getChildren().add(node0_3);
// 三级
TreeNode node0_3_0 = new TreeNode("Java");
node0_3_0.setParent(node0_3);
node0_3.getChildren().add(node0_3_0);
TreeNode node0_3_1 = new TreeNode("Groovy");
node0_3_1.setParent(node0_3);
node0_3.getChildren().add(node0_3_1);
TreeNode node0_3_2 = new TreeNode("javascript");
node0_3_2.setParent(node0_3);
node0_3.getChildren().add(node0_3_2);
// 一级
TreeNode node1 = new TreeNode("Hazel");
node1.setParent(rootNode);
rootNode.getChildren().add(node1);
// 二级
TreeNode node1_0 = new TreeNode("life");
node1_0.setParent(node1);
node1.getChildren().add(node1_0);
// 二级
TreeNode node1_1 = new TreeNode("美食");
node1_1.setParent(node1);
node1.getChildren().add(node1_1);
// 二级
TreeNode node1_2 = new TreeNode("旅游");
node1_2.setParent(node1);
node1.getChildren().add(node1_2);
return rootNode;
}
private void printNode(TreeNode node, int level) {
String preStr = "";
for (int i = 0; i < level; i++) {
preStr += "|----";
}
System.out.println(preStr + node.getName());
for (TreeNode children : node.getChildren()) {
printNode(children, level + 1);
}
}
}
第四步：创建日志输出配置文件：
log4j.properties
# Output pattern : date [thread] priority category - message log4j.rootLogger=info, Console #Console log4j.appender.Console=org.apache.log4j.ConsoleAppender log4j.appender.Console.layout=org.apache.log4j.PatternLayout log4j.appender.Console.layout.ConversionPattern=%d [%t] %-5p [%c] - %m%n log4j.logger.org.hibernate.tool.hbm2ddl=debug log4j.logger.org.hibernate.test=info
[四]、测试结果
测试添加方法，输出日志如下：
========>测试添加 start <======== ========>测试添加 end <======== ========>读取 start <======== -----> get root node: -----> 输出树形结构如下: micmiu.com |----Michael |----|----J2EE |----|----SOA |----|----NoSQL |----|----编程语言 |----|----|----Java |----|----|----Groovy |----|----|----javascript |----Hazel |----|----life |----|----美食 |----|----旅游 ========>读取 end <========
[四]、测试结果
测试添加方法，输出日志如下：
========>测试添加 start <======== ========>测试添加 end <======== ========>读取 start <======== -----> get root node: -----> 输出树形结构如下: micmiu.com |----Michael |----|----J2EE |----|----SOA |----|----NoSQL |----|----编程语言 |----|----|----Java |----|----|----Groovy |----|----|----javascript |----Hazel |----|----life |----|----美食 |----|----旅游 ========>读取 end <========
--------------------------------------------------------------
public class NodeManage {
private static NodeManage nodeManage= new NodeManage();
private NodeManage(){}//因为要使用单例，所以将其构造方法私有化
//向外提供一个接口
public static NodeManage getInstanse(){
return nodeManage;
}
/**
* 创建树
* @param filePath 需要创建树目录的根目录
*/
public void createNode(String dir) {
Session session = null;
try {
session = HibernateUtils.getSession();
session.beginTransaction();
File root = new File(dir);
//因为第一个节点无父节点，因为是null
this.saveNode(root, session, null, 0);
session.getTransaction().commit();
} catch (HibernateException e) {
e.printStackTrace();
session.getTransaction().rollback();
} finally {
HibernateUtils.closeSession(session);
}
}
/**
* 保存节点对象至数据库
* @param file 节点所对应的文件
* @param session session
* @param parent 父节点
* @param level 级别
*/
public void saveNode(File file, Session session, Node parent, int level) {
if (file == null || !file.exists()){
return;
}
//如果是文件则返回true,则表示是叶子节点，否则为目录，非叶子节点
boolean isLeaf = file.isFile();
Node node = new Node();
node.setName(file.getName());
node.setLeaf(isLeaf);
node.setLevel(level);
node.setParent(parent);
session.save(node);
//进行循环迭代子目录
File[] subFiles = file.listFiles();
if (subFiles != null && subFiles.length > 0){
for (int i = 0; i < subFiles.length ; i++){
this.saveNode(subFiles[i], session, node, level + 1);
}
}
}
/**
* 输出树结构
* @param id
*/
public void printNodeById(int id) {
Session session = null;
try {
session = HibernateUtils.getSession();
session.beginTransaction();
Node node = (Node)session.get(Node.class, 1);
printNode(node);
session.getTransaction().commit();
} catch (HibernateException e) {
e.printStackTrace();
session.getTransaction().rollback();
} finally {
HibernateUtils.closeSession(session);
}
}
private void printNode(Node node) {
if (node == null){
return;
}
int level = node.getLevel();
if (level > 0){
for (int i = 0; i < level; i++){
System.out.print(" |");
}
System.out.print("--");
}
System.out.println(node.getName() + (node.isLeaf() ? "" : "[" + node.getChildren().size() + "]"));
Set children = node.getChildren();
for (Iterator iter = children.iterator(); iter.hasNext(); ){
Node child = (Node)iter.next();
printNode(child);
}
}
}