Hibernate基础之十一：树状结构遍历

一：TreeNode

树结构的一个节点，

主键是ID，具体内容是value

双向连接俩外键，分别是父节点pid，和子节点的集合children

 

@Entity
@Table(name="t_TreeNode")
publicclass TreeNode
{
    privateint id;
    private String value;

    private TreeNode pid;//父节点id
    private Set<TreeNode> children = new HashSet<TreeNode>(); //子节点id


    @Id
    @GeneratedValue
    publicint getId() {
        return id;
    }
    @OneToMany(cascade=(CascadeType.ALL),mappedBy="pid")//级联用ALL
    public Set<TreeNode> getChildren() {
        return children;
    }
    @ManyToOne
    @JoinColumn(name="p_Id")//指定外键名称，不指定的默认值是group_Id
    public TreeNode getPid() {
        return pid;
    }

@Entity
@Table(name="t_TreeNode")
public class TreeNode 
{
	private int id;
	private String value;
	
	private TreeNode pid;//父节点id
	private Set<TreeNode> children = new HashSet<TreeNode>(); //子节点id


	@Id
	@GeneratedValue
	public int getId() {
		return id;
	}
	@OneToMany(cascade=(CascadeType.ALL),mappedBy="pid")//级联用ALL
	public Set<TreeNode> getChildren() {
		return children;
	}
	@ManyToOne
	@JoinColumn(name="p_Id")//指定外键名称，不指定的默认值是group_Id
	public TreeNode getPid() {
		return pid;
	}
	

 

 

 

二：存储

设置双向的关联

 

@Test
publicvoid testIN() {
    Session session = HibernateUtil.getSessionFactory().getCurrentSession();
       session.beginTransaction();

       TreeNode root = new TreeNode();
       root.setValue("root");

       TreeNode top1 = new TreeNode();
       top1.setValue("top1");
       TreeNode top2 = new TreeNode();
       top2.setValue("top2");

       TreeNode sub1_1 = new TreeNode();
       sub1_1.setValue("sub1_1");
       TreeNode sub1_2 = new TreeNode();
       sub1_2.setValue("sub1_2");

       root.getChildren().add(top1);//正向
       root.getChildren().add(top2);
       top1.getChildren().add(sub1_1);
       top1.getChildren().add(sub1_2);

       sub1_1.setPid(top1);//反向
       sub1_2.setPid(top1);
       top1.setPid(root);
       top2.setPid(root);

       session.save(root);//因为设置级联，所以存储g时候也把u1和u2存上了。

       session.getTransaction().commit();
       HibernateUtil.getSessionFactory().close();
}

	@Test
	public void testIN() {	
		Session session = HibernateUtil.getSessionFactory().getCurrentSession();
        session.beginTransaction();

        TreeNode root = new TreeNode();
        root.setValue("root");
        
        TreeNode top1 = new TreeNode();
        top1.setValue("top1");
        TreeNode top2 = new TreeNode();
        top2.setValue("top2");
        
        TreeNode sub1_1 = new TreeNode();
        sub1_1.setValue("sub1_1");
        TreeNode sub1_2 = new TreeNode();
        sub1_2.setValue("sub1_2");
        
        root.getChildren().add(top1);//正向
        root.getChildren().add(top2);
        top1.getChildren().add(sub1_1);
        top1.getChildren().add(sub1_2);
        
        sub1_1.setPid(top1);//反向
        sub1_2.setPid(top1);
        top1.setPid(root);
        top2.setPid(root);
          
        session.save(root);//因为设置级联，所以存储g时候也把u1和u2存上了。

        session.getTransaction().commit();
        HibernateUtil.getSessionFactory().close();         
	}
	

 

 

 

三：遍历

递归遍历

 

@Test
publicvoid testOut() {

    Session session = HibernateUtil.getSessionFactory().getCurrentSession();
       session.beginTransaction();

       TreeNode node = (TreeNode)session.get(TreeNode.class, 1);
       print(node);


       session.getTransaction().commit();
       HibernateUtil.getSessionFactory().close();
}

publicvoid print(TreeNode n)
{
       System.out.println(n.getValue());
       for(TreeNode child : n.getChildren())
       {
        print(child);
       }
}

	@Test
	public void testOut() {
		
		Session session = HibernateUtil.getSessionFactory().getCurrentSession();
        session.beginTransaction();
        
        TreeNode node = (TreeNode)session.get(TreeNode.class, 1);
        print(node);

        
        session.getTransaction().commit();
        HibernateUtil.getSessionFactory().close();
	}
	
	public void print(TreeNode n)
	{
        System.out.println(n.getValue());
        for(TreeNode child : n.getChildren())
        {
        	print(child);
        }
	}