HibernateTools实现pojo类 数据库schma mapping映射的相互转换 二
接着上一篇博客:HibernateTools实现pojo类 数据库schma mapping映射的相互转换
思路二:由数据库表,生成Mapping映射文件和POJO类。
虽然可以实现,但个人觉着先设计数据库,然后再生成类不符合Hibernate的面对对象持久化的思维方式。好了,还是说步骤吧,首先在test数据库建立两张表,分别为course表和teacher表
-- ---------------------------- -- Table structure for course -- ---------------------------- DROP TABLE IF EXISTS `course`; CREATE TABLE `course` ( `id` int(11) NOT NULL, `name` varchar(255) DEFAULT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8; -- ---------------------------- -- Table structure for teacher -- ---------------------------- DROP TABLE IF EXISTS `teacher`; CREATE TABLE `teacher` ( `id` int(11) NOT NULL, `name` varchar(255) DEFAULT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8;建好表后,在eclipse项目上右键-->new,如下图,选择框中的第三项,这个reveng.xml文件用于配置 选择要生成POJO类的数据库表。
选择上篇博客中创建的Console configuration项,点Database schema框下的refresh,之后可以看到test数据库,单击就出现了course和teacher表,全选后点击Include,之后点finish,如下图
再来到Hibernate Code Generation Configuration窗体,首先配置下Output directory输出目录,在尽挨着的复选框打上勾,然后在package栏写上生成文件要输出到哪个包,并选择刚配置好的reveng.xml文件
配置要输出的项,这里选定前两项,生成.java和.hbm.xml,就是我们想要的POJO类和Mapping映射文件。之后点击run就好了。
结果如下图:
生成的Mapping映射文件的代码
<?xml version="1.0"?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd"> <!-- Generated 2014-5-31 11:19:19 by Hibernate Tools 4.0.0 --> <hibernate-mapping> <class name="org.hibernate.test.Course" table="course" catalog="test"> <id name="id" type="int"> <column name="id" /> <generator class="assigned" /> </id> <many-to-one name="teacher" class="org.hibernate.test.Teacher" fetch="select"> <column name="teacherId" not-null="true" /> </many-to-one> <property name="name" type="string"> <column name="name" /> </property> </class> </hibernate-mapping>
<?xml version="1.0"?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd"> <!-- Generated 2014-5-31 11:19:19 by Hibernate Tools 4.0.0 --> <hibernate-mapping> <class name="org.hibernate.test.Teacher" table="teacher" catalog="test"> <id name="id" type="int"> <column name="id" /> <generator class="assigned" /> </id> <property name="name" type="string"> <column name="name" /> </property> <set name="courses" table="course" inverse="true" lazy="true" fetch="select"> <key> <column name="teacherId" not-null="true" /> </key> <one-to-many class="org.hibernate.test.Course" /> </set> </class> </hibernate-mapping>
生成的POJO类:
package org.hibernate.test; // Generated 2014-5-31 11:19:19 by Hibernate Tools 4.0.0 /** * Course generated by hbm2java */ public class Course implements java.io.Serializable { private int id; private Teacher teacher; private String name; public Course() { } public Course(int id, Teacher teacher) { this.id = id; this.teacher = teacher; } public Course(int id, Teacher teacher, String name) { this.id = id; this.teacher = teacher; this.name = name; } public int getId() { return this.id; } public void setId(int id) { this.id = id; } public Teacher getTeacher() { return this.teacher; } public void setTeacher(Teacher teacher) { this.teacher = teacher; } public String getName() { return this.name; } public void setName(String name) { this.name = name; } }
package org.hibernate.test; // Generated 2014-5-31 11:19:19 by Hibernate Tools 4.0.0 import java.util.HashSet; import java.util.Set; /** * Teacher generated by hbm2java */ public class Teacher implements java.io.Serializable { private int id; private String name; private Set courses = new HashSet(0); public Teacher() { } public Teacher(int id) { this.id = id; } public Teacher(int id, String name, Set courses) { this.id = id; this.name = name; this.courses = courses; } public int getId() { return this.id; } public void setId(int id) { this.id = id; } public String getName() { return this.name; } public void setName(String name) { this.name = name; } public Set getCourses() { return this.courses; } public void setCourses(Set courses) { this.courses = courses; } }
到此我们就完成了由数据库表生成POJO类和Mapping映射文件的过程
思路三:由Mapping映射文件生成数据库DDL和POJO类
首先,新建一个Mapping文件,这里在项目中建立Department.hbm.xml。
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd" > <hibernate-mapping> <class name="org.hibernate.test.Department" table="DEPARTMENT"> <id name="id" type="int"> <column name="ID" /> <generator class="increment"></generator> </id> <property name="name" type="java.lang.String"> <column name="NAME" /> </property> </class> </hibernate-mapping>
接下来建一个新的Console Configuration文件,基本配置和上文中配置的过程一样,最关键的是加入mapping文件。
接下来,改下Hibernate Code Generation Configuration就好了,首选选择新配置的Console Configuration文件
接下来选择要生成的Schema和.Java文件,然后run就可以了。
最终结果如图:
生成的DDL代码为
create table DEPARTMENT (ID integer not null, NAME varchar(255), primary key (ID));</span>
POJO类:
package org.hibernate.test; // Generated 2014-5-31 16:23:27 by Hibernate Tools 4.0.0 /** * Department generated by hbm2java */ public class Department implements java.io.Serializable { private int id; private String name; public Department() { } public Department(String name) { this.name = name; } public int getId() { return this.id; } public void setId(int id) { this.id = id; } public String getName() { return this.name; } public void setName(String name) { this.name = name; } }
好了,至此POJO类,Mapping文件和数据库表相互转化就都介绍完了,当然这是借助eclipse的插件实现的,熟悉使用ant的朋友也可以借助ant脚本来实现,具体的教程去google吧。这里推荐下HibernateTools的官方教程,包含了eclipse插件和ant脚本两种实现方式,非常全面。
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