1.创建项目,项目名称hibernatedemo12,目录结构如图所示
2.在项目中创建lib目录存储jar文件,目录结构如图所示
3.在src目录中创建实体Bean Comment,包名(com.mycompany.demo.bean),如图所示
4.实体Bean Comment的内容如下
package com.mycompany.demo.bean;
import java.util.Set;
public class Comment {
private int id;
private String name;
private Comment parentComment;
private Set<Comment> childrenComments;
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 Comment getParentComment() {
return parentComment;
}
public void setParentComment(Comment parentComment) {
this.parentComment = parentComment;
}
public Set<Comment> getChildrenComments() {
return childrenComments;
}
public void setChildrenComments(Set<Comment> childrenComments) {
this.childrenComments = childrenComments;
}
}
5.在src目录中创建实体Bean Comment的映射文件Comment.hbm.xml,包名(com.mycompany.demo.bean),如图所示
6.映射文件Comment.hbm.xml的内容如下
<?xml version="1.0" encoding="utf-8"?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD//EN" "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd"> <!-- package:指定<class/>所在的包 --> <hibernate-mapping package="com.mycompany.demo.bean"> <!-- name:类名 table:表名 catalog:数据库名称,默认为hibernate.cfg.xml中配置的数据库名称 --> <class name="Comment" table="comment"> <meta attribute="class-description"> This class contains the comment detail. </meta> <!-- name:属性名 colum:列名 --> <id name="id" type="int" column="id"> <!-- increment:hibernate维护主键值 identity:数据库自增长 sequence:序列 native:根据不同的数据库选择生成策略 uuid:通过UUID算法生成,实际使用较多 assigned:手工设置 --> <generator class="native"/> </id> <!-- length:字节长度 type:字段类型,支持java和hibernate类型 not-null:非空约束 unique:唯一性约束 --> <property name="name" column="name" type="string" length="50" not-null="true" unique="false"/> <!-- 多对一 --> <many-to-one name="parentComment" class="Comment" column="pid" cascade="save-update"></many-to-one> <!-- none:不使用级联 save-update:save(),update(),saveOrUpdate()级联操作 delete:delete()级联删除关联对象 all:对关联对象级联所有操作 delete-orphan:删除所有和当前对象解除关系的对象 all-delete-orphan:包含all和delete-orphan的所有操作 --> <set name="childrenComments" cascade="save-update" inverse="true"> <key column="pid"/> <one-to-many class="Comment"/> </set> </class> </hibernate-mapping>
7.在src目录中创建工具类 HbnUtil,包名(com.mycompany.demo.util),如图所示
8.工具类 HbnUtil的内容如下
package com.mycompany.demo.util;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
public class HbnUtil {
private static SessionFactory sessionFactory;
public static Session getSession(){
if(sessionFactory == null || sessionFactory.isClosed()){
sessionFactory = new Configuration().configure().buildSessionFactory();
}
return sessionFactory.getCurrentSession();
}
}
9.在src目录中创建Hibernate的配置文件hibernate.cfg.xml,如图所示
10.Hibernate的配置文件hibernate.cfg.xml的内容如下
<?xml version="1.0" encoding="utf-8"?> <!DOCTYPE hibernate-configuration SYSTEM "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd"> <hibernate-configuration> <session-factory> <!-- 方言,可以从Hibernate核心jar(hibernate-core-x.x.x.Finall.jar) 文件中的or.hibernate.dialect包中找到相应的类,类的全名就是 --> <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property> <!-- 驱动 --> <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property> <!-- 数据库连接地址 --> <property name="hibernate.connection.url">jdbc:mysql://localhost:3306/test</property> <!-- 用户名 --> <property name="hibernate.connection.username"> root </property> <!-- 密码 --> <property name="hibernate.connection.password"></property> <!-- create:每次都新创建,如果存在就删除 create-drop:创建新表,sessionFactory关闭,表会删除 update :表字段增加,会同步,字段减少不同步,数据改变会同步修改 --> <property name="hibernate.hbm2ddl.auto">update</property> <!-- 输出sql --> <property name="hibernate.show_sql">true</property> <!-- 格式化sql --> <property name="hibernate.format_sql">true</property> <!-- 事务环境一个线程对一个事务 thread:本地事务环境 jta:分布式事务环境 SpringSessionContext:用于ssh整合 --> <property name="hibernate.current_session_context_class">thread</property> <!-- 使用c3p0数据源 --> <property name="hibernate.connection.provider_class"> org.hibernate.c3p0.internal.C3P0ConnectionProvider</property> <!-- List of XML mapping files --> <mapping resource="com/mycompany/demo/bean/Comment.hbm.xml"/> </session-factory> </hibernate-configuration>
11.在项目中创建test目录存储测试文件,文件名称TestApp,包名(com.mycompany.demo.bean),目录结构如图所示
12.TestApp测试类的内容如下
package com.mycompany.demo.bean;
import org.hibernate.Session;
import org.junit.Before;
import org.junit.Test;
import com.mycompany.demo.util.HbnUtil;
public class TestApp {
private Session session;
@Before
public void init(){
session = HbnUtil.getSession();
}
/*
* 自关联
*/
@Test
public void testOneToManyOneself(){
try {
session.beginTransaction();
Comment parentComment = new Comment();
parentComment.setName("父评论");
Comment sub1 = new Comment();
sub1.setName("小子1");
sub1.setParentComment(parentComment);
Comment sub2 = new Comment();
sub2.setName("小子2");
sub2.setParentComment(parentComment);
session.save(sub1);
session.save(sub2);
session.getTransaction().commit();
} catch (Exception e) {
session.getTransaction().rollback();
e.printStackTrace();
}
}
}
时间： 2024-09-30 11:42:04