Hibernate多对一（注解）

 package cqvie.yjq.Util;

 import java.util.List;

 import org.hibernate.Query;
 import org.hibernate.Session;
 import org.hibernate.SessionFactory;
 import org.hibernate.Transaction;
 import org.hibernate.cfg.AnnotationConfiguration;

 final public class HibernataUtil {

     private static SessionFactory sessionFactory = null;
     //使用线程局部模式
     private static ThreadLocal<Session> threadLocal = new ThreadLocal<Session>();
     private HibernataUtil() {};
     static {
         sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory();
     }
     //获取全新的session
     public static Session openSession() {
         return sessionFactory.openSession();
     }
     //获取和线程关联的session
     public static Session getCurrentSession() {
         Session session = threadLocal.get();
         //判断是否得到
         if(session == null) {
             session = sessionFactory.openSession();
             //把session对象设置到threadLocal，相当于已经和线程绑定
             threadLocal.set(session);
         }
         return session;
     }

     //提供一个统一的修改和删除方法（批量）
     public static void executeUpdate(String hql, String[] parameters) {
         Session s = null;
         Transaction ts = null;
         try {
             s = openSession();
             ts = s.beginTransaction();
             Query query = s.createQuery(hql);
             //先判断是否有参数要绑定
             if(parameters != null && parameters.length > 0) {
                 for(int i=0;i<parameters.length;i++) {
                     query.setString(i, parameters[i]);
                 }
             }
             query.executeUpdate();
             ts.commit();
         } catch(Exception e) {
             e.printStackTrace();
             throw new RuntimeException();
         } finally {
             if(s != null && s.isOpen()) {
                 s.close();
             }
         }
     }

     //提供一个统一的添加方法
     public static void sava(Object obj) {
         Session s = null;
         Transaction ts = null;
         try {
             s = openSession();
             ts = s.beginTransaction();
             s.save(obj);
             ts.commit();
         } catch (Exception e) {
             if(ts != null) {
                 ts.rollback();
             }
             throw new RuntimeException();
         } finally {
             if(s != null && s.isOpen()) {
                 s.close();
             }
         }
     }

     //提供一个统一的查询方法（分页）
     @SuppressWarnings("unchecked")
     public static List executeQueryByPage(String hql, String[] parameters, int pageSize, int pageNow) {
         Session s = null;
         List list = null;
         try {
             s = openSession();
             Query query = s.createQuery(hql);
             //先判断是否有参数要绑定
             if(parameters != null && parameters.length > 0) {
                 for(int i=0;i<parameters.length;i++) {
                     query.setString(i, parameters[i]);
                 }
             }
             query.setFirstResult((pageNow-1)*pageSize).setMaxResults(pageSize);
             list = query.list();
         } catch(Exception e) {
             e.printStackTrace();
             throw new RuntimeException();
         } finally {
             if(s != null && s.isOpen()) {
                 s.close();
             }
         }
         return list;
     }

     //提供一个统一的查询方法 hql 形式 from 类 where 条件=?
     @SuppressWarnings("unchecked")
     public List executeQuery(String hql, String[] parameters) {
         Session s = null;
         List list = null;
         try {
             s = openSession();
             Query query = s.createQuery(hql);
             //先判断是否有参数要绑定
             if(parameters != null && parameters.length > 0) {
                 for(int i=0;i<parameters.length;i++) {
                     query.setString(i, parameters[i]);
                 }
             }
             list = query.list();
         } catch(Exception e) {
             e.printStackTrace();
             throw new RuntimeException();
         } finally {
             if(s != null && s.isOpen()) {
                 s.close();
             }
         }
         return list;
     }
 }

工具类HibernateUtil

 package cqvie.yjq.domain;

 import javax.persistence.Column;
 import javax.persistence.Entity;
 import javax.persistence.GeneratedValue;
 import javax.persistence.Id;
 import javax.persistence.Table;

 import org.hibernate.annotations.GenericGenerator;

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

     private static final long serialVersionUID = 2076837731637660357L;

     @Id
     @GenericGenerator(name = "generator", strategy = "uuid")
     @GeneratedValue(generator = "generator")
     @Column(name = "depid", unique = true, nullable = false)//nullable = false表示该字段不为空
     private String depid;
     @Column(name = "name", nullable = false, length = 20)
     private String name;

     public String getDepid() {
         return depid;
     }
     public void setDepid(String depid) {
         this.depid = depid;
     }
     public String getName() {
         return name;
     }
     public void setName(String name) {
         this.name = name;
     }

 }

实体类Department

 package cqvie.yjq.domain;

 import javax.persistence.Column;
 import javax.persistence.Entity;
 import javax.persistence.GeneratedValue;
 import javax.persistence.Id;
 import javax.persistence.JoinColumn;
 import javax.persistence.ManyToOne;
 import javax.persistence.Table;

 import org.hibernate.annotations.GenericGenerator;

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

     private static final long serialVersionUID = 8640757615294410421L;

     @Id
     @GenericGenerator(name = "generator", strategy = "uuid")
     @GeneratedValue(generator = "generator")
     @Column(name = "stuid", unique = true, nullable = false)
     private String stuid;
     @Column(name = "name", nullable = false, length = 20)
     private String name;
     @ManyToOne
     @JoinColumn(name = "depid")
     private Department dept;

     public String getStuid() {
         return stuid;
     }
     public void setStuid(String stuid) {
         this.stuid = stuid;
     }
     public String getName() {
         return name;
     }
     public void setName(String name) {
         this.name = name;
     }
     public Department getDept() {
         return dept;
     }
     public void setDept(Department dept) {
         this.dept = dept;
     }

 }

实体类Student

 package cqvie.yjq.View;

 import org.hibernate.Session;
 import org.hibernate.Transaction;

 import cqvie.yjq.Util.HibernataUtil;
 import cqvie.yjq.domain.Department;
 import cqvie.yjq.domain.Student;

 public class Test {

     public static void main(String[] args) {

         //通过获取session让hibernate框架运行(config --> 加载hibernate.cfg.xml)
         Session session = null;
         Transaction tx = null;
         try {
             session =  HibernataUtil.getCurrentSession();
             tx = session.beginTransaction();

             Student stu = new Student();
             stu.setName("王敏");

             Department dep = new Department();
             dep.setName("财务部");
             Department dep1 = new Department();
             dep1.setName("人事部");

             stu.setDept(dep1);

             session.save(stu);
             session.save(dep);
             session.save(dep1);

             tx.commit();
         } catch (Exception e) {
             if(tx != null) {
                 tx.rollback();
             }
         } finally {
             if(session != null && session.isOpen()) {
                 session.close();
             }
         }
     }

 }

测试类

 <?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">

 <!-- Generated by MyEclipse Hibernate Tools.                   -->
 <hibernate-configuration>

 <session-factory>
     <property name="dialect">
         org.hibernate.dialect.MySQLDialect
     </property>
     <property name="connection.url">
         jdbc:mysql://localhost:3306/student
     </property>
     <property name="connection.username">root</property>
     <property name="connection.password">123</property>
     <property name="connection.driver_class">
         com.mysql.jdbc.Driver
     </property>
     <property name="myeclipse.connection.profile">MySQL</property>
     <property name="show_sql">true</property>
     <!-- 格式化显示SQL -->
     <property name="format_sql">true</property>

     <property name="current_session_context_class">thread</property>
     <!-- 让hibernate自动创建表  update:如果没有表则创建，有表则更新 -->
     <property name="hbm2ddl.auto">create</property>
     <mapping class="cqvie.yjq.domain.Department" />
     <mapping class="cqvie.yjq.domain.Student" />
 </session-factory>

 </hibernate-configuration>

Hibernate.cfg.xml