hibernate双向多对一(一对多)及自身一对多关联

双向多对一(一对多)关联是最最常见的关联关系

javabean如下：

/**
 * 
 * 双向的一对多（多对一）
 * 少的一端,需要对多的一端进行集合的引用
 */
public class Account {

	private int id;
	private String accName;
	
	//对多端对象集合的引用
	private Set setOrders;
	
	public Account(){
		
	}

	/**
	 * @return the id
	 */
	public int getId() {
		return id;
	}

	/**
	 * @param id the id to set
	 */
	public void setId(int id) {
		this.id = id;
	}

	/**
	 * @return the accName
	 */
	public String getAccName() {
		return accName;
	}

	/**
	 * @param accName the accName to set
	 */
	public void setAccName(String accName) {
		this.accName = accName;
	}

	/**
	 * @return the setOrders
	 */
	public Set getSetOrders() {
		return setOrders;
	}

	/**
	 * @param setOrders the setOrders to set
	 */
	public void setSetOrders(Set setOrders) {
		this.setOrders = setOrders;
	}
	
	
}

/**
 * 
 * 双向的一对多（多对一）
 * 多的一端需要对少的一端进行对象的引用
 */
public class Orders {

	private int id;
	private String orderNum;
	private Date orderTime;
	private Account account;
	
	public Orders(){
		
	}

	/**
	 * @return the id
	 */
	public int getId() {
		return id;
	}

	/**
	 * @param id the id to set
	 */
	public void setId(int id) {
		this.id = id;
	}

	/**
	 * @return the orderNum
	 */
	public String getOrderNum() {
		return orderNum;
	}

	/**
	 * @param orderNum the orderNum to set
	 */
	public void setOrderNum(String orderNum) {
		this.orderNum = orderNum;
	}

	/**
	 * @return the orderTime
	 */
	public Date getOrderTime() {
		return orderTime;
	}

	/**
	 * @param orderTime the orderTime to set
	 */
	public void setOrderTime(Date orderTime) {
		this.orderTime = orderTime;
	}

	public Account getAccount() {
		return account;
	}

	public void setAccount(Account account) {
		this.account = account;
	}
	
}

映射文件：

生成的数据库表：

@Test
	public void add(){
		Transaction tx=null;
		Session session=null;
		try{
			session=HibernateUtils.getSession();
			tx=session.beginTransaction();
			Account account=new Account();
			account.setAccName("lm");
			Orders order1=new Orders();
			order1.setOrderNum("100");
			order1.setOrderTime(new Date());
			//session.save(order1);
			
			Orders order2=new Orders();
			order2.setOrderNum("10061");
			order2.setOrderTime(new Date());
			//session.save(order2);
			
			order1.setAccount(account);
			order2.setAccount(account);
			Set setOrders=new HashSet();
			setOrders.add(order1);
			setOrders.add(order2);
			account.setSetOrders(setOrders);
			
			session.save(account);
			tx.commit();
		}catch(HibernateException he){
			if(tx!=null){
				tx.rollback();
			}
			he.printStackTrace();
		}finally{
			HibernateUtils.closeSession(session);
		}
	}

自身关联：

javabean如下：

/**
 * 
 * 双向一对多或多对一 自身关联
 * 
 */
public class Category {

	private int id;
	private String name;
	
	//如果把Category看成是多的一端
	private Category parent;
	
	//如果把Category看成是少的一端,则需要对多的一端进行对象集合的引用
	private Set clist;
	
	public Category(){
		
	}

	/**
	 * @return the id
	 */
	public int getId() {
		return id;
	}

	/**
	 * @param id the id to set
	 */
	public void setId(int id) {
		this.id = id;
	}

	/**
	 * @return the name
	 */
	public String getName() {
		return name;
	}

	/**
	 * @param name the name to set
	 */
	public void setName(String name) {
		this.name = name;
	}

	/**
	 * @return the parent
	 */
	public Category getParent() {
		return parent;
	}

	/**
	 * @param parent the parent to set
	 */
	public void setParent(Category parent) {
		this.parent = parent;
	}

	/**
	 * @return the clist
	 */
	public Set getClist() {
		return clist;
	}

	/**
	 * @param clist the clist to set
	 */
	public void setClist(Set clist) {
		this.clist = clist;
	}
	
}

映射文件

数据库表：

测试代码：

@Test
	public void add(){
		Transaction tx=null;
		Session session=null;
		try{
			session=HibernateUtils.getSession();
			tx=session.beginTransaction();
			//添加一级分类
			Category c1=new Category();
			c1.setName("computer");
			
			session.save(c1);
			
			//添加二级分类
			Category c2=new Category();
			c2.setName("java");
			c2.setParent(c1);
			session.save(c2);
			//添加二级分类
			Category c3=new Category();
			c3.setName(".net");
			c3.setParent(c1);
			session.save(c3);
			tx.commit();
		}catch(HibernateException he){
			if(tx!=null){
				tx.rollback();
			}
			he.printStackTrace();
		}finally{
			HibernateUtils.closeSession(session);
		}
	}
	

数据结构：