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;
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。