hibernate不自动生成数据表 但是没自动建表？

<?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>
     <!-- 数据库的基本配置 -->
<property name="hibernate.connection.class.driver_class">com.mysql.jdbc.Driver</property>
<property name="hibernate.connection.url">jdbc:mysql:///task</property>
<property name="hibernate.connection.username">root</property>
<property name="hibernate.connection.password"></property> <!-- mysql方言 下面的方言支持事物 -->
<property name="hibernate.dialect">org.hibernate.dialect.MySQLInnoDBDialect</property>
<!-- 数据库的策略 -->
<property name="hbm2ddl.auto">update</property>
<!-- 关联映射文件 -->
<mapping resource="com/tao/bean/User.hbm.xml" /> </session-factory>
</hibernate-configuration><?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!-- Generated 2017-9-6 14:16:18 by Hibernate Tools 3.4.0.CR1 -->
<hibernate-mapping>
    <class name="com.tao.bean.User" table="USERS">
        <id name="id" type="int" access="field">
            <column name="ID" />
            <generator class="assigned" />
        </id>
        <property name="name" type="java.lang.String">
            <column name="NAME" />
        </property>
        <property name="password" type="java.lang.String">
            <column name="PASSWORD" />
        </property>
    </class>
</hibernate-mapping>
package com.tao.bean;public class User {
private int id;
private String name;
private String password; public User() {
} public User(String name, String password) {
this.name = name;
this.password = password;
} public void setName(String name) {
this.name = name;
} public String getName() {
return name;
} public String getPassword() {
return password;
} public void setPassword(String password) {
this.password = password;
} @Override
public String toString() {
return "个人信息： id=" + id + ", name=" + name + ", password=" + password;
}}
package com.tao.dao;import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
import org.hibernate.service.ServiceRegistry;
import org.hibernate.service.ServiceRegistryBuilder;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;import com.tao.bean.User;public class DaoUserTest {
// 创建4个对象
SessionFactory sessionFactory = null;
Session session = null;
Transaction ta = null;
Configuration configuration = null; @SuppressWarnings("deprecation")
@Before
public void init() {
configuration = new Configuration().configure();
// 4.把注册信息传入ServiceRegistry接口中，Hibernate 4.x的做法
ServiceRegistry buildServiceRegistry = new ServiceRegistryBuilder().applySettings(configuration.getProperties())
.buildServiceRegistry();
sessionFactory = configuration.buildSessionFactory(buildServiceRegistry);
// 5.获取session
session = sessionFactory.openSession();
// 6.开启事务
ta = session.beginTransaction();
} // 加载
// @Test
// public void testGet() {
// User user = (User) session.get(User.class, 1);
// System.out.println(user);
// } @Test
public void save() {
User user = new User("aa", "aa");
session.save(user);
} @After
public void close() {
// 8.事务提交
ta.commit();
// 9.释放所有资源
session.close();
sessionFactory.close();
}
}