今天忙了一整天,终于搭建好了我的第一个Hibernate程序,中间关于hibernate.cfg.
首先在你的eclipse中安装Hibernate Tools插件方便创建cfg.cml与hbm.
奥添加yi
当然在最前面还要添加hibernate jar包,musql driver等,由于我使用maven管理项目,因此直接在maven的pom文件中添加就可以了。
在hibernate.cfg.
1 <??> 2 <!DOCTYPE hibernate-configuration PUBLIC 3 "-//Hibernate/Hibernate Configuration DTD 3.0//EN" 4 "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd"> 5 <hibernate-configuration> 6 <session-factory > 7 <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property> 8 <property name="hibernate.connection.password">admin</property> 9 <property name="hibernate.connection.url">jdbc:mysql://localhost:3306/hibernate?characterEncoding=utf-8</property>10 <property name="hibernate.connection.username">root</property>11 <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>12 <!-- 在控制台输出SQL语句 -->13 <property name="show_sql">true</property>14 <!-- Hibernate启动时自动创建表结构 -->15 <property name="hbm2ddl.auto">create</property>16 <!-- 不加 可能出现异常 -->17 <property name="current_sesson_context_class">thread</property>18 <!-- 指定Cat类为Hibernate实体类 -->19 <mapping resource="config/Cat.hbm./>20 </session-factory>21 </hibernate-configuration>
第九行url后面的 hibernate?characterEncoding=utf-8 是hibernate要操作的数据库名称,需要你自己先创建:
create database hibernate character set 'utf8'
19行Cat类是需要你自己创建的POJO实体类,实体类(Entity)是指与数据库有映射关系的Java类使用@Entity后Cat就被申明为了一个实体类。实体类还需配置对应的表名(@Table),主键(@Id),普通属性(@Column)对应列名等。
1 package com.lxiao.model; 2 3 4 import java.util.Date; 5 6 import javax.persistence.Column; 7 import javax.persistence.Entity; 8 import javax.persistence.GeneratedValue; 9 import javax.persistence.GenerationType; 10 import javax.persistence.Id; 11 import javax.persistence.JoinColumn; 12 import javax.persistence.ManyToOne; 13 import javax.persistence.Table; 14 import javax.persistence.Temporal; 15 import javax.persistence.TemporalType; 16 17 @Entity 18 @Table(name="tb_cat") 19 public class Cat { 20 21 @Id 22 @GeneratedValue(strategy = GenerationType.AUTO) 23 private Integer Id; 24 25 @Column(name = "name") 26 private String name; 27 28 @Column(name = "description") 29 private String description; 30 31 @Column(name = "age") 32 private Integer age; 33 34 @Column(name="sex") 35 private String sex; 36 37 @ManyToOne 38 @JoinColumn(name = "mother_id") 39 private Cat mother; 40 41 @Temporal(TemporalType.TIMESTAMP) 42 @Column(name = "createDate") 43 private Date createDate; 44 45 public Integer getId() { 46 return Id; 47 } 48 49 public void setId(Integer id) { 50 Id = id; 51 } 52 53 public String getName() { 54 return name; 55 } 56 57 public void setName(String name) { 58 this.name = name; 59 } 60 61 public String getDescription() { 62 return description; 63 } 64 65 public void setDescription(String description) { 66 this.description = description; 67 } 68 69 public Integer getAge() { 70 return age; 71 } 72 73 public void setAge(Integer age) { 74 this.age = age; 75 } 76 77 public String getSex() { 78 return sex; 79 } 80 81 public void setSex(String sex) { 82 this.sex = sex; 83 } 84 85 public Cat getMother() { 86 return mother; 87 } 88 89 public void setMother(Cat mother) { 90 this.mother = mother; 91 } 92 93 public Date getCreateDate() { 94 return createDate; 95 } 96 97 public void setCreateDate(Date createDate) { 98 this.createDate = createDate; 99 }100 101 }
值得一提的是,该POJO类在定义玩le私有变量后,可以用eclipse自动生成getter,setter方法,免去了手写的枯燥。
然后创建Cat.hbm.
然后一路next就可以了,最后就在hibernte.cfg.
然后我们写一个HibernateUtil类来加载config文件hibernate.cfg.
1 package com.lxiao.hibernate; 2 3 import org.hibernate.SessionFactory; 4 import org.hibernate.cfg.Configuration; 5 6 public class HibernateUtil { 7 private static final SessionFactory factory; 8 9 static{10 try{11 factory = new Configuration().configure("config/hibernate.cfg.).buildSessionFactory();12 }catch(Throwable e){13 System.out.println("Initial sesionFactory failed..."+e);14 throw new ExceptionInInitializerError(e);15 }16 }17 18 public static SessionFactory getSessionFactory(){19 return factory;20 }21 }
原标题:我的Hibernate入门
关键词:Hibernate