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。
作者:xqf309 发表于2014-5-31 22:27:37
原文链接