Hibernate 自定义主键生成类

最新推荐文章于 2021-12-31 04:05:40 发布

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最新推荐文章于 2021-12-31 04:05:40 发布

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分类专栏：数据库文章标签： Hibernate Java

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本文介绍了一种自定义的主键生成策略，该策略利用日期和时间戳生成唯一标识符，并通过Hibernate框架进行实现。此外，还展示了如何在POJO类中应用此策略。

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KeyGen类
用于生成形如 yyyyMMDD+序号形式的主键


package keyGen;
public class OrderKeyGen implements IdentifierGenerator {

	private static SimpleDateFormat preFix = new SimpleDateFormat("yyyyMMdd");

	@Override
	public synchronized Serializable generate(SessionImplementor arg0,
			Object arg1) throws HibernateException {
		String datePart = preFix.format(new Date());
		String idString = datePart + System.currentTimeMillis() % 99;
		return idString;
	}

}

POJO类定义


package db;

@Entity
@Table(name = "t_diykey", catalog = "test")
public class TDiykey implements java.io.Serializable {

	// Fields

	private String dbid;
	private String notes;

	// Constructors

	/** default constructor */
	public TDiykey() {
	}

	/** full constructor */
	public TDiykey(String notes) {
		this.notes = notes;
	}

	// Property accessors
	@GenericGenerator(name = "generator", strategy = "keyGen.OrderKeyGen")
	@Id
	@GeneratedValue(generator = "generator")
	@Column(name = "dbid", unique = true, nullable = false, length = 10)
	public String getDbid() {
		return this.dbid;
	}

	public void setDbid(String dbid) {
		this.dbid = dbid;
	}

	@Column(name = "notes", length = 20)
	public String getNotes() {
		return this.notes;
	}

	public void setNotes(String notes) {
		this.notes = notes;
	}

}

测试类


public class MyDIYKeyTest {
    public static void main(String[] args) {
		Session session = HibernateSessionFactory.getSession();
		Transaction tx = session.beginTransaction();

		TDiykey tDiykey = new TDiykey();
		tDiykey.setNotes("aaaa");

		session.save(tDiykey);
		tx.commit();
		HibernateSessionFactory.closeSession();
	}