hibernate添加数据入门小案例

1.建立一个java项目，在目录下新建一个lib文件夹引入hibernate架包如图所示：

2. 新建com.LHB.domain包，在包中分别创建一个Employee.java和Employee.hbm.xml文件，

Employee.java中的代码如下：

 package com.LHB.domain;

 import java.util.Date;
 //该pojo/javabean/domain按照规范应当序列化，目的是可以唯一的表示该对象呢，同时可以在网络和文件传输
 public class Employee implements java.io.Serializable {
     private static final long serialVersionUID = 1L;
     private Integer id;
     private String name;
     private String email;
     private Date hiredate;
     public Integer getId() {
         return id;
     }
     public void setId(Integer id) {
         this.id = id;
     }
     public String getName() {
         return name;
     }
     public void setName(String name) {
         this.name = name;
     }
     public String getEmail() {
         return email;
     }
     public void setEmail(String email) {
         this.email = email;
     }
     public Date getHiredate() {
         return hiredate;
     }
     public void setHiredate(Date hiredate) {
         this.hiredate = hiredate;
     }

 }

Employee.hbm.xml映射文件配置如下：

 <?xml version="1.0" encoding="utf-8"?>
 <!-- 映射文件通过DTD来指定格式 -->
 <!DOCTYPE hibernate-mapping PUBLIC
     "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
     "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
 <!-- 该文件用于配置domain对象和表的映射关系 -->
 <hibernate-mapping package="com.LHB.domain">
     <class name="Employee" table="employee" >
         <!-- id元素用于指定主键属性 -->
         <!--
         <id name="id" column="id" type="java.lang.Integer">
             该元素用来指定主键生成的策略hilo native increment sequence uuid
             <generator class="sequence">
                 <param name="sequence">emp_seq</param>
             </generator>
         </id>
          -->
          <!-- 在更改数据库时对主键生成策略做了修改 -->
          <id name="id" column="id" type="java.lang.Integer">
              <generator class="increment"></generator>
          </id>
         <!-- 如果id号希望用户自己设定，而不是由数据库MySQL -->
        <!--  <id name="id" column="id" type="java.lang.Integer">
             <generator class="assigned"/>
         </id> -->
         <!-- 对其它属性还要配置 -->
         <property name="name" type="java.lang.String">
             <column name="name" not-null="false"  />
         </property>
         <property name="email" type="java.lang.String">
             <column name="email" not-null="false" />
         </property>
         <property name="hiredate" type="java.util.Date">
             <column name="hiredate" not-null="false" />
         </property>
     </class>

 </hibernate-mapping>

3.在项目src文件下创建hibernate.cfg.xml配置文件，其中的配置信息如下：

 <?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">

 <hibernate-configuration>
     <session-factory>
         <!-- 配置使用的driver -->
         <property name="connection.driver_class">com.mysql.jdbc.Driver</property>
         <property name="connection.username">root</property>
         <property name="connection.password">123456</property>
         <property name="connection.url">jdbc:mysql://localhost:3306/test</property>
         <!-- 配置dialect方言，明确告诉hibernate连接哪种数据库 -->
         <property name="dialect">org.hibernate.dialect.MySQLDialect</property>
         <!-- 显示出对应的sql语句 -->
         <property name="show_sql">true</property>
         <!-- 让hibernate给我们自动创建表  creat:如果mysql中没有该表则创建,如果有表则删除再创建
              update：如果没有表则创建新表，如果有表则看表结构有没有变化,如果有变化则创建新表-->
         <property name="hbm2ddl.auto">update</property>
         <!-- 指定管理的对象映射文件 -->
         <mapping resource="com/LHB/domain/Employee.hbm.xml"/>

     </session-factory>
 </hibernate-configuration>

4. 创建一个测试类TestMain

 package com.LHB.view;

 import java.util.Date;

 import org.hibernate.SessionFactory;
 import org.hibernate.Transaction;
 import org.hibernate.cfg.Configuration;
 import org.hibernate.classic.Session;

 import com.LHB.domain.Employee;
 import com.LHB.util.MySessionFactory;

 public class TestMain {

     public static void main(String[] args) {
         // TODO Auto-generated method stub

         updateEmp();
         //addEmployee();
     }
     /**
      * 删除用户
      */
     private static void delEmp() {
         //删除
         //获取一个session
         Session session = MySessionFactory.getSessionFactory().openSession();
         Transaction transaction = session.beginTransaction();
         try {
             //修改1.先获取该雇员，然后删除
             Employee employee=(Employee) session.load(Employee.class, new Integer(3));
             session.delete(employee);
             transaction.commit();
             session.close();

         }catch (Exception e) {
             if(transaction!=null) {
                 transaction.rollback();
             }

             throw new RuntimeException(e.getMessage());
         } finally {
             //关闭session
             if(session!=null&&session.isOpen()) {
                 session.close();
             }

         }
     }
     /**
      * 更新用户
      */
     private static void updateEmp() {
         //修改用户
         //获取一个会话
         /*Session session = MySessionFactory.getSessionFactory().openSession();

         Transaction transaction = session.beginTransaction();
         //修改用户1.获取要修改的用户，2.修改
         //load是可以通过主键属性，获取该对象实例，《----》表的记录对应
         Employee employee = (Employee)session.load(Employee.class, new Integer(3));
         employee.setName("张三");
         transaction.commit();
         session.close();
         */
         //添加事务回滚优化之后
         Session session = MySessionFactory.getSessionFactory().openSession();
         Transaction transaction = null;
         try {
             transaction = session.beginTransaction();
             //do...
             Employee employee = (Employee)session.load(Employee.class, new Integer(1));
             //用户指定id号
             //employee.setId(new Integer(100));
             employee.setName("李四");
             employee.setEmail("lisi@sohu.com");

             /*//异常
             int i=9/0;
             //....
 */            transaction.commit();

         }catch (Exception e) {
             if(transaction!=null) {
                 transaction.rollback();
             }

             throw new RuntimeException(e.getMessage());
         } finally {
             //关闭session
             if(session!=null&&session.isOpen()) {
                 session.close();
             }

         }

     }
     /**
      * 添加用户
      */
     public static void addEmployee() {
         //使用hibernate完成crud操作
         //现在不使用service，直接测试
         //1.创建Configuration,该对象用于读取hibernate.cfg.xml并完成初始化
         Configuration configuration = new Configuration().configure();
         //2.创建SessionFactory【这是一个会话工厂，是一个重量级的对象】
         SessionFactory sessionFactory = configuration.buildSessionFactory();
         //3.创建Session,相当于jdbc中的Connection
         Session  session = sessionFactory.openSession();
         //4.对于hibernate，要求在进行增加，删除，修改的时候使用事物提交
         Transaction transaction = session.beginTransaction();

         try {

             //添加一个雇员
             Employee employee = new Employee();
             employee.setName("zhangsan");
             employee.setEmail("zhangsan@126.com");
             employee.setHiredate(new Date());

             //保存，把对象保存到数据库
             session.save(employee);//相当于insert into....[被hibernate封装]
             transaction.commit();
             session.close();

         }catch (Exception e) {
             if(transaction!=null) {
                 transaction.rollback();
             }

             throw new RuntimeException(e.getMessage());
         } finally {
             //关闭session
             if(session!=null&&session.isOpen()) {
                 session.close();
             }

         }
     }

 }