API 或代码：Hibernate 3 和 4 之间的区别？

我已经粘贴了休眠3配置文件、SessionFactory 类来配置此 config.xml 和带有 JPA 注释的 bean。我想知道我是否在使用休眠4那么代码级别的上下文会发生什么变化，或者外行语言的非常广泛的差异或进步。

休眠配置文件

    <?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>
        <property name="hibernate.connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
        <property name="hibernate.connection.url">jdbc:oracle:thin:@192.168.2.144:1521:xe</property>
        <property name="hibernate.connection.username">prateek</property>
        <property name="connection.password">prateek</property>
        <property name="connection.pool_size">1</property>
        <property name="hibernate.dialect">org.hibernate.dialect.OracleDialect</property>
        <property name="show_sql">true</property>
        <property name="hbm2ddl.auto">create</property>
        <mapping class="com.vaannila.domain.User1" />
    </session-factory>
</hibernate-configuration>

建立连接的静态java类（SessionFactory Helper）

import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;

public class SessionFactoryHelper {
    private static final SessionFactory sessionFactory;

    static {
        try {            
            /*
             * Build a SessionFactory object from session-factory configuration 
             * defined in the hibernate.cfg.xml file. In this file we register 
             * the JDBC connection information, connection pool, the hibernate 
             * dialect that we used and the mapping to our hbm.xml file for each 
             * POJO (Plain Old Java Object).
             * 
             */
            sessionFactory = new Configuration().configure().buildSessionFactory();
        } catch (Throwable e) {
            System.err.println("Error in creating SessionFactory object." 
                + e.getMessage());
            throw new ExceptionInInitializerError(e);
        }
    }

    /*
     * A static method for other application to get SessionFactory object 
     * initialized in this helper class.
     * 
     */
    public static SessionFactory getSessionFactory() {
        return sessionFactory;
    }
}

豆类

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

@Entity
@Table(name="USER1")
public class User1 {

    private Long id;
    private String name;
    private String gender;
    private String country;
    private String aboutYou;
    private Boolean mailingList;

    @Id
    @GeneratedValue
    @Column(name="USER_ID") 
    public Long getId() {
        return id;
    }
    public void setId(Long id) {
        this.id = id;
    }

    @Column(name="USER_NAME")
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }

    @Column(name="USER_GENDER")
    public String getGender() {
        return gender;
    }
    public void setGender(String gender) {
        this.gender = gender;
    }

    @Column(name="USER_COUNTRY")
    public String getCountry() {
        return country;
    }
    public void setCountry(String country) {
        this.country = country;
    }

    @Column(name="USER_ABOUT_YOU")
    public String getAboutYou() {
        return aboutYou;
    }
    public void setAboutYou(String aboutYou) {
        this.aboutYou = aboutYou;
    }

    @Column(name="USER_MAILING_LIST")
    public Boolean getMailingList() {
        return mailingList;
    }
    public void setMailingList(Boolean mailingList) {
        this.mailingList = mailingList;
    }

}

休眠配置文件

文件 hibernate.cfg.xml 没问题。 hibernate-configuration-3.0.dtd 中的版本仍然是 3.0，这可能看起来令人困惑，但事实就是如此。 DTD 未更新。也许您想使用以 hibernate 为前缀的名称，例如hibernate.show_sql代替show_sql。属性名称可以从以下位置找到文档 http://docs.jboss.org/hibernate/orm/4.1/manual/en-US/html_single/#configuration-sessionfactory。通常使用的 DTD_location 是http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd（与..sourceforge...），但两者都应该有效。

建设会话工厂

正如你从API http://docs.jboss.org/hibernate/orm/4.1/javadocs/org/hibernate/cfg/Configuration.html#buildSessionFactory%28%29, buildSessionFactory 已弃用。这是 4.x 中的构建方式：

Configuration conf = new Configuration();
conf.configure();
serviceRegistry = new ServiceRegistryBuilder().applySettings(conf.getProperties()).buildServiceRegistry();        
sessionFactory = configuration.buildSessionFactory(serviceRegistry);

文档中的许多地方仍然不是最新的。

注释实体

一般来说，无需更改 bean 类中的映射。原因是您正在使用普通的 JPA 映射，并且 Hibernate 3 是 JPA 规范中描述的实现。