学步园

Hibernate高级实体关联映射之多值的实体关联(用组件类实现三重关联,单向导航)

这里只演示了单向导航的例子。

这个例子从Hibernate高级实体关联映射之多值的实体关联(多对多关联的两种思路之二)这篇bog演变而来。这个例子增加了一个实体，MyClass中有这三个实体的外键。请看代码 ：

pom.xml:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"<br /> xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"><br /> <modelVersion>4.0.0</modelVersion><br /> <groupId>hibernateTest</groupId><br /> <artifactId>hibernateTest</artifactId><br /> <version>1.0-SNAPSHOT</version><br /> <packaging>jar</packaging><br /> <name>hibernateTest</name><br /> <url>http://maven.apache.org</url><br /> <dependencies><br /> <dependency><br /> <groupId>junit</groupId><br /> <artifactId>junit</artifactId><br /> <version>3.8.1</version><br /> <scope>test</scope><br /> </dependency><br /> <dependency><br /> <groupId>org.hibernate</groupId><br /> <artifactId>hibernate-core</artifactId><br /> <version>3.3.1.GA</version><br /> </dependency><br /> <dependency><br /> <groupId>org.slf4j</groupId><br /> <artifactId>slf4j-nop</artifactId><br /> <version>1.5.2</version><br /> </dependency><br /> <dependency><br /> <groupId>javassist</groupId><br /> <artifactId>javassist</artifactId><br /> <version>3.4.GA</version><br /> </dependency><br /> <dependency><br /> <groupId>c3p0</groupId><br /> <artifactId>c3p0</artifactId><br /> <version>0.9.1</version><br /> </dependency><br /> <dependency><br /> <groupId>com.oracle</groupId><br /> <artifactId>ojdbc14</artifactId><br /> <version>10.2.0.3.0</version><br /> <scope>runtime</scope><br /> </dependency><br /> </dependencies><br /> <build><br /> <finalName>hibernateTest</finalName><br /> <resources><br /> <resource><br /> <directory>src/main/resources</directory><br /> </resource><br /> <resource><br /> <directory>src/main/java</directory><br /> <excludes><br /> <exclude>**/*.java</exclude><br /> </excludes><br /> </resource><br /> </resources><br /> <plugins><br /> <plugin><br /> <artifactId>maven-compiler-plugin</artifactId><br /> <configuration><br /> <source>1.6</source><br /> <target>1.6</target><br /> <encoding>UTF-8</encoding><br /> </configuration><br /> </plugin><br /> </plugins><br /> </build><br /> </project>  

resources/hibernate.cfg.xml:

<?xml version="1.0" encoding="utf-8"?><br /> <!DOCTYPE hibernate-configuration<br /> PUBLIC "-//Hibernate/Hibernate Configuration DTD//EN"<br /> "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd"><br /> <hibernate-configuration><br /> <session-factory name="sessionFactory"><br /> <!-- 指定连接数据库所用的驱动 --><br /> <property name="hibernate.connection.driver_class">oracle.jdbc.driver.OracleDriver</property><br /> <!-- 指定连接数据库的url，hibernate连接的数据库名 --><br /> <property name="hibernate.connection.url">jdbc:oracle:thin:@localhost:1521:XE</property><br /> <property name="hibernate.connection.useUnicode">true</property><br /> <property name="hibernate.connection.characterEncoding">gbk</property><br /> <!-- 指定连接数据库的用户名 --><br /> <property name="hibernate.connection.username">system</property><br /> <!-- 指定连接数据库的密码 --><br /> <property name="hibernate.connection.password">password</property><br /> <!-- 指定连接池里最大连接数 --><br /> <property name="hibernate.c3p0.max_size">20</property><br /> <!-- 指定连接池里最小连接数 --><br /> <property name="hibernate.c3p0.min_size">5</property><br /> <!-- 指定连接池里连接的超时时长,以秒为单位 --><br /> <property name="hibernate.c3p0.timeout">120</property><br /> <!-- 指定连接池里最大缓存多少个Statement对象 --><br /> <property name="hibernate.c3p0.max_statements">100</property><br /> <!-- 每隔XX秒检查连接池里的空闲连接 ，单位是秒 --><br /> <property name="hibernate.c3p0.idle_test_period">120</property><br /> <!-- 当连接池里面的连接用完的时候，C3P0一次获取的新的连接数 --><br /> <property name="hibernate.c3p0.acquire_increment">2</property><br /> <!-- 指定数据库方言 --><br /> <property name="dialect">org.hibernate.dialect.OracleDialect</property><br /> <!-- 显示Hibernate持久化操作所生成的SQL --><br /> <property name="show_sql">true</property><br /> <!-- 将SQL脚本进行格式化后再输出 --><br /> <property name="hibernate.format_sql">true</property><br /> <!-- 罗列所有的映射文件 --><br /> <mapping resource="pojo/Student.hbm.xml" /><br /> <mapping resource="pojo/Teacher.hbm.xml" /><br /> <mapping resource="pojo/Group.hbm.xml" /><br /> </session-factory><br /> </hibernate-configuration>  

pojo/Teacher.java:

package pojo;<br /> import java.io.Serializable;<br /> import java.util.ArrayList;<br /> import java.util.Collection;<br /> public class Teacher implements Serializable{<br /> private String teacher_id;<br /> private String teacher_name;<br /> private int teacher_age;<br /> private Collection<MyClass> myClassList = new ArrayList<MyClass>();</p> <p> public String getTeacher_id() {<br /> return teacher_id;<br /> }<br /> @SuppressWarnings("unused")<br /> private void setTeacher_id(String teacher_id) {<br /> this.teacher_id = teacher_id;<br /> }<br /> public String getTeacher_name() {<br /> return teacher_name;<br /> }<br /> public void setTeacher_name(String teacher_name) {<br /> this.teacher_name = teacher_name;<br /> }<br /> public int getTeacher_age() {<br /> return teacher_age;<br /> }<br /> public void setTeacher_age(int teacher_age) {<br /> this.teacher_age = teacher_age;<br /> }<br /> public Collection<MyClass> getMyClassList() {<br /> return myClassList;<br /> }<br /> public void setMyClassList(Collection<MyClass> myClassList) {<br /> this.myClassList = myClassList;<br /> }<br /> }<br />  

pojo/Teacher.hbm.xml:

<?xml version="1.0" encoding="UTF-8"?><br /> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD//EN"<br /> "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"><br /> <hibernate-mapping package="pojo"><br /> <class name="Teacher" table="A_TEACHER" dynamic-insert="true" dynamic-update="true"><br /> <id name="teacher_id" column="TEACHER_ID" type="string"><br /> <generator class="uuid.hex" /><br /> </id><br /> <property name="teacher_name" column="TEACHER_NAME" type="string"/><br /> <property name="teacher_age" column="TEACHER_AGE" type="integer"/><br /> <bag name="myClassList" table="A_CLASS"><br /> <key column="TEACHER_ID"/><br /> <composite-element class="MyClass"><br /> <parent name="teacher"/><br /> <many-to-one name="student" column="STUDENT_ID" not-null="true" class="Student"/><br /> <many-to-one name="group" column="GROUP_ID" not-null="true" class="Group"/><br /> <property name="className" column="CLASSNAME" type="string"/><br /> <property name="schoolName" column="SCHOOLNAME" type="string"/><br /> <property name="createTime" column="CREATETIME" type="calendar"/><br /> </composite-element><br /> </bag><br /> </class><br /> </hibernate-mapping>  

pojo/Student.java:

package pojo;<br /> import java.io.Serializable;<br /> import java.util.ArrayList;<br /> import java.util.Collection;<br /> public class Student implements Serializable{<br /> private String student_id;<br /> private String student_name;<br /> private int student_age; </p> <p> public String getStudent_id() {<br /> return student_id;<br /> }<br /> @SuppressWarnings("unused")<br /> private void setStudent_id(String student_id) {<br /> this.student_id = student_id;<br /> }<br /> public String getStudent_name() {<br /> return student_name;<br /> }<br /> public void setStudent_name(String student_name) {<br /> this.student_name = student_name;<br /> }<br /> public int getStudent_age() {<br /> return student_age;<br /> }<br /> public void setStudent_age(int student_age) {<br /> this.student_age = student_age;<br /> }<br /> }

pojo/Student.hbm.xml:

<?xml version="1.0" encoding="UTF-8"?><br /> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD//EN"<br /> "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"><br /> <hibernate-mapping package="pojo"><br /> <class name="Student" table="A_STUDENT" dynamic-insert="true" dynamic-update="true"><br /> <id name="student_id" column="STUDENT_ID" type="string"><br /> <generator class="uuid.hex" /><br /> </id><br /> <property name="student_name" column="STUDENT_NAME" type="string"/><br /> <property name="student_age" column="STUDENT_AGE" type="integer"/><br /> </class><br /> </hibernate-mapping>  

pojo/Group.java:

package pojo;<br /> import java.io.Serializable;<br /> public class Group implements Serializable{<br /> private String group_id;<br /> private String group_name;<br /> private int group_num;</p> <p> public String getGroup_id() {<br /> return group_id;<br /> }<br /> @SuppressWarnings("unused")<br /> private void setGroup_id(String group_id) {<br /> this.group_id = group_id;<br /> }<br /> public String getGroup_name() {<br /> return group_name;<br /> }<br /> public void setGroup_name(String group_name) {<br /> this.group_name = group_name;<br /> }<br /> public int getGroup_num() {<br /> return group_num;<br /> }<br /> public void setGroup_num(int group_num) {<br /> this.group_num = group_num;<br /> }<br /> }<br />  

pojo/Group.hbm.xml:

<?xml version="1.0" encoding="UTF-8"?><br /> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD//EN"<br /> "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"><br /> <hibernate-mapping package="pojo"><br /> <class name="Group" table="A_GROUP" dynamic-insert="true" dynamic-update="true"><br /> <id name="group_id" column="GROUP_ID" type="string"><br /> <generator class="uuid.hex" /><br /> </id><br /> <property name="group_name" column="GROUP_NAME" type="string"/><br /> <property name="group_num" column="GROUP_NUM" type="integer"/><br /> </class><br /> </hibernate-mapping>  

pojo/MyClass.java:

package pojo;<br /> import java.io.Serializable;<br /> import java.util.Calendar;<br /> public class MyClass implements Serializable {</p> <p> //值类型的组件类不需要标识符，也就是不用主键类<br /> private String className;<br /> private String schoolName;<br /> private Calendar createTime;<br /> private Student student;<br /> private Teacher teacher;<br /> private Group group;</p> <p> public MyClass(){}</p> <p> public MyClass(String className,String schoolName,Student student,Teacher teacher,Group group){<br /> this.className = className;<br /> this.schoolName = schoolName;<br /> this.student = student;<br /> this.teacher = teacher;<br /> this.createTime = Calendar.getInstance();<br /> this.group = group;<br /> //不需要关联代码了<br /> }<br /> public String getClassName() {<br /> return className;<br /> }<br /> public void setClassName(String className) {<br /> this.className = className;<br /> }<br /> public String getSchoolName() {<br /> return schoolName;<br /> }<br /> public void setSchoolName(String schoolName) {<br /> this.schoolName = schoolName;<br /> }<br /> public Calendar getCreateTime() {<br /> return createTime;<br /> }<br /> public void setCreateTime(Calendar createTime) {<br /> this.createTime = createTime;<br /> }<br /> public Student getStudent() {<br /> return student;<br /> }<br /> public void setStudent(Student student) {<br /> this.student = student;<br /> }<br /> public Teacher getTeacher() {<br /> return teacher;<br /> }<br /> public void setTeacher(Teacher teacher) {<br /> this.teacher = teacher;<br /> }<br /> public Group getGroup() {<br /> return group;<br /> }<br /> public void setGroup(Group group) {<br /> this.group = group;<br /> }</p> <p> //如果是用set集合，这里还要实现equals()和hashCode()方法<br /> }<br />  

util/HibernateUtil.java:

package util;<br /> import org.hibernate.SessionFactory;<br /> import org.hibernate.cfg.Configuration;<br /> public class HibernateUtil {<br /> private static SessionFactory sessionFactory;<br /> static{<br /> try {<br /> sessionFactory = new Configuration().configure().buildSessionFactory();<br /> } catch (Throwable e) {<br /> throw new ExceptionInInitializerError(e);<br /> }<br /> }<br /> public static SessionFactory getSessionFactory(){<br /> return sessionFactory;<br /> }<br /> public static void shutdown(){<br /> getSessionFactory().close();<br /> }<br /> }<br />  

util/Manager.java:

package util;<br /> import org.hibernate.Session;<br /> import org.hibernate.Transaction;<br /> import pojo.Group;<br /> import pojo.MyClass;<br /> import pojo.Student;<br /> import pojo.Teacher;<br /> public class Manager {<br /> public static void main(String[] args) {</p> <p> Teacher t = new Teacher();<br /> t.setTeacher_name("fhd");<br /> t.setTeacher_age(35);</p> <p> Student s = new Student();<br /> s.setStudent_name("fuhaidong");<br /> s.setStudent_age(30);</p> <p> Group g = new Group();<br /> g.setGroup_name("group111");<br /> g.setGroup_num(80);</p> <p> Session session = HibernateUtil.getSessionFactory().openSession();<br /> Transaction transaction = session.beginTransaction();</p> <p> session.save(t);<br /> session.save(s);<br /> session.save(g);<br /> MyClass my = new MyClass("class1111111", "schoolName1111111",s,t,g);<br /> //添加<br /> t.getMyClassList().add(my);<br /> System.out.println(t.getMyClassList().size());<br /> session.flush();<br /> //删除<br /> t.getMyClassList().remove(my);</p> <p> transaction.commit();<br /> session.close();<br /> }<br /> }<br />  

表结构：

A_TEACHER表：<br /> TEACHER_ID,<br /> TEACHER_NAME,<br /> TEACHER_AGE,<br /> A_STUDENT表：<br /> STUDENT_ID,<br /> STUDENT_NAME,<br /> STUDENT_AGE<br /> A_GROUP表：<br /> GROUP_ID,<br /> GROUP_NAME,<br /> GROUP_NUM<br /> A_CLASS表：<br /> TEACHER_ID,<br /> STUDENT_ID,<br /> GROUP_ID,<br /> CLASSNAME,<br /> SCHOOLNAME,<br /> CREATETIME 

上例是用bag实现的关联，用set也可以实现, 但list,map不知道可不可以，不过没有测试！！