MyEclipse中hibernate反向工程实例（一对多关联）

1、数据库设计

       实例对象为工作人员和部门，关系为一个部门对应多个工作人员，一个工作人员只属于一个部门

       见表语句如下：（先用Navicat建的表，然后导出的sql语句），数据库名称为test

SET FOREIGN_KEY_CHECKS=0;DROP TABLE IF EXISTS `t_department`;CREATE TABLE `t_department` (  `id` int(11) NOT NULL auto_increment,  `departmentname` varchar(40) NOT NULL,  `departmentlocation` varchar(100) NOT NULL,  PRIMARY KEY  (`id`)) ENGINE=InnoDB DEFAULT CHARSET=utf8;DROP TABLE IF EXISTS `t_user`;CREATE TABLE `t_user` (  `id` int(11) NOT NULL auto_increment,  `username` varchar(20) NOT NULL,  `password` varchar(20) NOT NULL,  `departmentid` int(11) NOT NULL,  PRIMARY KEY  (`id`),  KEY `departmentid` (`departmentid`),  CONSTRAINT `departmentid` FOREIGN KEY (`departmentid`) REFERENCES `t_department` (`id`)) ENGINE=InnoDB DEFAULT CHARSET=utf8;

 

2、使用MyEclipse反向工程生成配置文件和POJO类

   

第一步：配置数据源

1、打开MyEclipse，新建一个web工程，这里命名为hibernate_demo

2、打开数据库设置器：依次单击【window】-->【Show View】-->【Other…】如下图所示：

3、在弹出的窗口ShowView中选择DB Browser,如下图所示:

4、在DB Browser窗口中，选择显示的图标，单击右键执行新建命令，如下图示

5、弹出Database Driver对话框，在此会要求我们配置数据库的相关信息，具体设置如下图所示，设置完成，单击Finish.

                    

【第二步】引入hibernate配置文件

 

1、添加hibernate包：

选中我们的Web工程，依次单击鼠标右键-->MyEclipse-->Add HibernateCapabilities… 如下图所示：

2、在弹出的窗口中做如下设置：

【Next】，创建hibernate的配置文件

【Next】，指明hibernate与数据库的连接

     

【Next】，创建HibernateSessionFactory类，用来获得session。如果前面没有设置包名，要先单击New创建新的包。

    

单击【Finish】按钮

                     

接下来要给hibernate.cfg.xml文件添加属性：在properties处选择Add…，如下图所示：

单击【Add…】，在Hibernate Properties Wizard页面填入如下图所示信息，最后单击Ok。

show_sql：默认为false，如果为true，表示在程序运行时，会在控制台输出SQL语句，这有利于跟中Hibernate的运行状态。在开发和测试阶段，可以将该属性设置为true，以便跟踪、调试程序，在应用发布以后，应将该属性值设置为false，以减少应用的输出信息，提高运行性能。

 

【第三步】添加hibernate映射文件和POJO类

1、新建com.lqh.beans包

2、在前面设置的数据源上找到我们要操作的表：

在DB Browser中选中新建的数据源，单击鼠标右键并选择open connection..

输入数据库的用户名和密码，以创建连接：

找到刚才新建的test数据库，然后是TABLE，如下图所示：

              

生成POJO：

           

点击Next，配置映射类型（暂时未用到）

    

点击Next，配置反向工程细节

                                         

 

           点击finish即可完成，生成的映射文件以及POJO类如下：

               User.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"><!--     Mapping file autogenerated by MyEclipse Persistence Tools--><hibernate-mapping>    <class name="com.lqh.beans.User" table="t_user" catalog="test">        <id name="id" type="integer">            <column name="id" />            <generator class="native"></generator>        </id>        <many-to-one name="department" class="com.lqh.beans.Department" cascade="all" fetch="select">            <column name="departmentid" not-null="true" />        </many-to-one>        <property name="username" type="string">            <column name="username" length="20" not-null="true" />        </property>        <property name="password" type="string">            <column name="password" length="20" not-null="true" />        </property>    </class></hibernate-mapping>

 

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"><!--     Mapping file autogenerated by MyEclipse Persistence Tools--><hibernate-mapping>    <class name="com.lqh.beans.Department" table="t_department" catalog="test">        <id name="id" type="integer">            <column name="id" />            <generator class="native"></generator>        </id>        <property name="departmentname" type="string">            <column name="departmentname" length="40" not-null="true" />        </property>        <property name="departmentlocation" type="string">            <column name="departmentlocation" length="100" not-null="true" />        </property>        <set name="users" inverse="true">            <key>                <column name="departmentid" not-null="true" />            </key>            <one-to-many class="com.lqh.beans.User" />        </set>    </class></hibernate-mapping>

 

User.java

package com.lqh.beans;/** * User entity. @author MyEclipse Persistence Tools */public class User implements java.io.Serializable {// Fieldsprivate Integer id;private Department department;private String username;private String password;// Constructors/** default constructor */public User() {}/** full constructor */public User(Department department, String username, String password) {this.department = department;this.username = username;this.password = password;}// Property accessorspublic Integer getId() {return this.id;}public void setId(Integer id) {this.id = id;}public Department getDepartment() {return this.department;}public void setDepartment(Department department) {this.department = department;}public String getUsername() {return this.username;}public void setUsername(String username) {this.username = username;}public String getPassword() {return this.password;}public void setPassword(String password) {this.password = password;}}

Department.java

package com.lqh.beans;import java.util.HashSet;import java.util.Set;/** * Department entity. @author MyEclipse Persistence Tools */public class Department implements java.io.Serializable {// Fieldsprivate Integer id;private String departmentname;private String departmentlocation;private Set users = new HashSet(0);// Constructors/** default constructor */public Department() {}/** minimal constructor */public Department(String departmentname, String departmentlocation) {this.departmentname = departmentname;this.departmentlocation = departmentlocation;}/** full constructor */public Department(String departmentname, String departmentlocation,Set users) {this.departmentname = departmentname;this.departmentlocation = departmentlocation;this.users = users;}// Property accessorspublic Integer getId() {return this.id;}public void setId(Integer id) {this.id = id;}public String getDepartmentname() {return this.departmentname;}public void setDepartmentname(String departmentname) {this.departmentname = departmentname;}public String getDepartmentlocation() {return this.departmentlocation;}public void setDepartmentlocation(String departmentlocation) {this.departmentlocation = departmentlocation;}public Set getUsers() {return this.users;}public void setUsers(Set users) {this.users = users;}}

编写测试类代码，如下：

package com.lqh.test;import org.hibernate.Session;import org.junit.Test;import com.lqh.beans.Department;import com.lqh.beans.User;import com.lqh.utils.HibernateSessionFactory;public class HibernateTest {/** * 测试保存部门 */@Testpublic void testSaveDepartment() {Department department = new Department();department.setDepartmentlocation("清河小营东路");department.setDepartmentname("北京信息科技");Session session = HibernateSessionFactory.getSession();session.beginTransaction();session.save(department);session.getTransaction().commit();session.close();}/** * 测试保存用户，该用户已存在对应Department */@Testpublic void testSavaUser() {Session session = HibernateSessionFactory.getSession();session.beginTransaction();Department department = (Department) session.load(Department.class, 1);User user = new User();user.setUsername("hehe");user.setPassword("123455");user.setDepartment(department);session.save(user);session.getTransaction().commit();session.close();}/** * 测试保存用户，该用户对应的Department未存在数据库中*  此处注意，要将User.hbm.xml中的cascade设为all */@Testpublic void testSaveUserAndDepartment() {Session session = HibernateSessionFactory.getSession();session.beginTransaction();Department department = new Department();department.setDepartmentname("中央人民政府");department.setDepartmentlocation("北京");User user = new User();user.setUsername("UserAndDepartment");user.setPassword("123455");user.setDepartment(department);session.save(user);session.getTransaction().commit();session.close();}}

 

此外，还可在POJO类上生成注解，只需在以下两步注意即可：

 

上面这步并不是必须，选在3.2版本以上，默认就支持注解。

 

 

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