Hibernate初印象(helloworld)-1

参考文档：
http://docs.jboss.org/hibernate/orm/4.2/quickstart/en-US/html_single/#d5e57

JPA与Hibernate、ibatis等的关系有点类似于JDBC和mysqlDriver，oracleDriver的关系

JPA定义了一套标准的接口规范，Hibernate等框架去按照这套规范实现，Hibernate的作者也参与了JPA规范的定义。

mysql中创建表student

hibernate.cfg.xml

<?xml version='1.0' encoding='utf-8'?><!DOCTYPE hibernate-configuration PUBLIC        "-//Hibernate/Hibernate Configuration DTD 3.0//EN"        "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd"><hibernate-configuration>    <session-factory>        <!-- Database connection settings -->        <property name="connection.driver_class">com.mysql.jdbc.Driver</property>        <property name="connection.url">jdbc:mysql://localhost/hibernate?serverTimezone=UTC</property>        <property name="connection.username">root</property>        <property name="connection.password">root</property>        <!-- JDBC connection pool (use the built-in) 一般用jndi-->        <!--<property name="connection.pool_size">1</property>-->        <!-- SQL dialect 方言-->        <property name="dialect">org.hibernate.dialect.MySQLDialect</property>        <!-- Enable Hibernate's automatic session context management 暂时注释掉  3.2以后-->        <!--<property name="current_session_context_class">thread</property>-->        <!-- Disable the second-level cache  禁用二级缓存-->        <property name="cache.provider_class">org.hibernate.cache.NoCacheRegionFactoryAvailableException</property>        <!-- Echo all executed SQL to stdout 要不要把生成的sql打印出来-->        <property name="show_sql">true</property>        <!-- Drop and re-create the database schema on startup hbm:hibernatemapping  ddl建表语句  要不要用hibernate自动生成建表语句  暂时注释-->        <!--<property name="hbm2ddl.auto">update</property>-->        <mapping resource="model/Student.hbm.xml"/>    </session-factory></hibernate-configuration>

student.java

package model;/** * Created by dongyu.liu on 2017-5-22. */public class Student {    private int id;    private String name;    private int age;    public int getId() {        return id;    }    public void setId(int id) {        this.id = id;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public int getAge() {        return age;    }    public void setAge(int age) {        this.age = age;    }}

Student.hbm.xml

<!DOCTYPE hibernate-mapping PUBLIC        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"        "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd"><hibernate-mapping package="model">    <!--table 属性不配就是默认-->    <class name="Student" >        <!-- id指属性  name  代表类中的属性  column可省略代表name和数据库名字一致-->        <id name="id" >            <generator class="increment"/>        </id>        <property name="name" />        <property name="age"/>    </class></hibernate-mapping>

测试

package model;import org.hibernate.Session;import org.hibernate.SessionFactory;import org.hibernate.cfg.Configuration;/** * Created by dongyu.liu on 2017-5-22. */public class TestStudent {    public static void main(String[] args) {       Student s = new Student();        s.setId(1);        s.setName("s1");        s.setAge(1);        Configuration cfg = new Configuration();        SessionFactory sf = cfg.configure().buildSessionFactory();        Session sessions = sf.openSession();        sessions.beginTransaction();        sessions.save(s);        sessions.getTransaction().commit();        sf.close();    }}

遇到的问题

1 .xml文件无法编译到class文件夹中，在pom.xml中增加配置

<build>    <finalName>hibernatetest</finalName>      <!-- xml文件正常编译到class目录中-->      <resources>          <resource>              <directory>src/main/java</directory>              <includes>                  <include>**/*.xml</include>              </includes>              <filtering>true</filtering>          </resource>      </resources>  </build>

1. The server time zone value ‘XXXXXX’ is unrecognized or represents more than one time zone.这个问题是时区不同步造成的，可以在hibernate.cfg.xml文件中在url后面添加参数：serverTimezone=UTC

 <property name="connection.url">jdbc:mysql://localhost/hibernate?serverTimezone=UTC</property>