树状结构实现与加载-优快云博客

本文介绍了一种基于Java和Hibernate的树状结构实现方法，包括部门类Org的设计及其关联关系，通过递归方式实现了组织结构的加载和展示。

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[align=center][size=x-large][color=red][b]树状结构Tree[/b][/color][/size][/align]

一、部门类Org.java


import java.util.HashSet;
import java.util.Set;

import javax.persistence.CascadeType;
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;

@Entity
public class Org {
	private int id;
	private String name;
	private Set<Org> children = new HashSet<Org>();
	private Org parent;
	@Id
	@GeneratedValue
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	@OneToMany(cascade=CascadeType.ALL, mappedBy="parent" ,fetche=FetcheType.EAGER)
	public Set<Org> getChildren() {
		return children;
	}
	public void setChildren(Set<Org> children) {
		this.children = children;
	}

	@ManyToOne
	@JoinColumn(name="parent_id")
	public Org getParent() {
		return parent;
	}
	public void setParent(Org parent) {
		this.parent = parent;
	}
}

二、递归输出


import java.util.Map;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.AnnotationConfiguration;
import org.hibernate.tool.hbm2ddl.SchemaExport;
import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.Test;

public class HibernateTreeTest {
	private static SessionFactory sessionFactory;

	@BeforeClass
	public static void beforeClass() {
		new SchemaExport(new AnnotationConfiguration().configure()).create(false, true);
		sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory();
	}
	@AfterClass
	public static void afterClass() {
		sessionFactory.close();
	}

	@Test
	public void testSave() {
		Org o = new Org();
		o.setName("总公司");
		Org o1 = new Org();
		o1.setName("分公司1");
		Org o2 = new Org();
		o2.setName("分公司2");
		Org o11 = new Org();
		o11.setName("分公司1下部门1");
		Org o12 = new Org();
		o12.setName("分公司1下部门2");

		o.getChildren().add(o1);
		o.getChildren().add(o2);
		o1.getChildren().add(o11);
		o1.getChildren().add(o12);
		o11.setParent(o1);
		o12.setParent(o1);
		o1.setParent(o);
		o2.setParent(o);


		Session session = sessionFactory.openSession();
		session.beginTransaction();
		session.save(o);

		session.getTransaction().commit();
		session.close();
	}
	@Test
	public void testLoad() {
		testSave();
		Session session = sessionFactory.openSession();
		session.beginTransaction();
		Org o = (Org)session.load(Org.class, 1);
		print(o, 0);
		session.getTransaction().commit();
		session.close();

	}

	private void print(Org o, int level) {
		String preStr = "";
		for(int i=0; i<level; i++) {
			preStr += "----";
		}
		System.out.println(preStr + o.getName());
		for(Org child : o.getChildren()) {
			print(child, level+1);
		}
	}
	@Test
	public void testSchemaExport() {
		new SchemaExport(new AnnotationConfiguration().configure()).create(false, true);
	}


	public static void main(String[] args) {
		beforeClass();
	}
}