HibernateTools實現pojo類 資料庫schma mapping映射的相互轉換 二

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接著上一篇部落格：HibernateTools實現pojo類 資料庫schma mapping映射的相互轉換

思路二：由資料庫表，產生Mapping對應檔和POJO類。

   儘管能夠實現，但個人覺著先設計資料庫，然後再產生類不符合Hibernate的面對對象持久化的思維方式。好了。還是說步驟吧。首先在test資料庫建立兩張表，分別為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;

建好表後，在eclipse項目上右鍵-->new,例如以，選擇框中的第三項，這個reveng.xml檔案用於配置 選擇要產生POJO類的資料庫表。

選擇上篇部落格中建立的Console configuration項。點Database schema框下的refresh。之後能夠看到test資料庫，單擊就出現了course和teacher表，全選後點擊Include,之後點finish，例如以

再來到Hibernate Code Generation Configuration視窗，首先配置下Output directory輸出檔案夾，在盡挨著的複選框打上勾，然後在package欄寫上組建檔案要輸出到哪個包，並選擇剛配置好的reveng.xml檔案

配置要輸出的項，這裡選定前兩項。產生.java和.hbm.xml，就是我們想要的POJO類和Mapping對應檔。之後點擊run就好了。

結果例如以：

產生的Mapping對應檔的代碼

<?
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>

產生的POJO類：

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 4.0.0import 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;}}

到此我們就完畢了由資料庫表產生POJO類和Mapping對應檔的過程

思路三：由Mapping對應檔產生資料庫DDL和POJO類

首先，建立一個Mapping檔案。這裡在項目中建立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>

接下來建一個新的Console Configuration檔案，基本配置和上文中配置的過程一樣，最關鍵的是增加mapping檔案。

接下來。改下Hibernate Code Generation Configuration就好了，首選選擇新配置的Console Configuration檔案

接下來選擇要產生的Schema和.Java檔案，然後run就能夠了。

終於結果

產生的DDL代碼為

create table DEPARTMENT (ID integer not null, NAME varchar(255), primary key (ID));</span>

POJO類：

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類，Mapping檔案和資料庫表相互轉化就都介紹完了。當然這是藉助eclipse的外掛程式實現的，熟悉使用ant的朋友也能夠藉助ant指令碼來實現，詳細的教程去google吧。

這裡推薦下HibernateTools的官方教程。包括了eclipse外掛程式和ant指令碼兩種實現方式，很全面。

HibernateTools實現pojo類 資料庫schma mapping映射的相互轉換 二