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();
            }
            
        }
    }

}