Hibernate高级实体关联映射之多值的实体关联(实体类实现三重关联)_hibernate框架带出实体中引的其他实体数据-优快云博客

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Hibernate高级实体关联映射之多值的实体关联(实体类实现三重关联)

这是参考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一),这篇blog实现的。

这里有四个实体类，四张表。其中A_ClASS表是关联表。

这里用set集实现的关联，使用bag也可以实现。map用另一种方法也可以实现三重关联。list是否可以就不确定了，没有测试！！！

pom.xml:

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

resources/hibernate.cfg.xml:

<?xml version="1.0" encoding="utf-8"?> <!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD//EN" "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd"> <hibernate-configuration> <session-factory name="sessionFactory">  <property name="hibernate.connection.driver_class">oracle.jdbc.driver.OracleDriver</property>  <property name="hibernate.connection.url">jdbc:oracle:thin:@localhost:1521:XE</property> <property name="hibernate.connection.useUnicode">true</property> <property name="hibernate.connection.characterEncoding">gbk</property>  <property name="hibernate.connection.username">system</property>  <property name="hibernate.connection.password">password</property>  <property name="hibernate.c3p0.max_size">20</property>  <property name="hibernate.c3p0.min_size">5</property>  <property name="hibernate.c3p0.timeout">120</property>  <property name="hibernate.c3p0.max_statements">100</property>  <property name="hibernate.c3p0.idle_test_period">120</property>  <property name="hibernate.c3p0.acquire_increment">2</property>  <property name="dialect">org.hibernate.dialect.OracleDialect</property>  <property name="show_sql">true</property>  <property name="hibernate.format_sql">true</property>  <mapping resource="pojo/Student.hbm.xml" /> <mapping resource="pojo/Teacher.hbm.xml" /> <mapping resource="pojo/Group.hbm.xml" /> <mapping resource="pojo/MyClass.hbm.xml" /> </session-factory> </hibernate-configuration>

pojo/Teacher.java:

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

pojo/Teacher.hbm.xml , 注意：<set>上必须inverse="true"

pojo/Student.java:

package pojo; import java.io.Serializable; import java.util.HashSet; import java.util.Set; public class Student implements Serializable{ private String student_id; private String student_name; private int student_age; private Set<MyClass> myClassList = new HashSet<MyClass>(); public String getStudent_id() { return student_id; } @SuppressWarnings("unused") private void setStudent_id(String student_id) { this.student_id = student_id; } public String getStudent_name() { return student_name; } public void setStudent_name(String student_name) { this.student_name = student_name; } public int getStudent_age() { return student_age; } public void setStudent_age(int student_age) { this.student_age = student_age; } public Set<MyClass> getMyClassList() { return myClassList; } public void setMyClassList(Set<MyClass> myClassList) { this.myClassList = myClassList; } }

pojo/Student.hbm.xml, 注意：<set>上必须inverse="true"

pojo/Group.java :

package pojo; import java.io.Serializable; import java.util.HashSet; import java.util.Set; public class Group implements Serializable{ private String group_id; private String group_name; private int group_num; private Set<MyClass> myClassList = new HashSet<MyClass>(); public String getGroup_id() { return group_id; } @SuppressWarnings("unused") private void setGroup_id(String group_id) { this.group_id = group_id; } public String getGroup_name() { return group_name; } public void setGroup_name(String group_name) { this.group_name = group_name; } public int getGroup_num() { return group_num; } public void setGroup_num(int group_num) { this.group_num = group_num; } public Set<MyClass> getMyClassList() { return myClassList; } public void setMyClassList(Set<MyClass> myClassList) { this.myClassList = myClassList; } }

pojo/Group.hbm.xml, 注意：<set>上必须inverse="true":

pojo/MyClass.java:

package pojo; import java.io.Serializable; import java.util.Calendar; public class MyClass implements Serializable { public static class Id implements Serializable{ private Id(){} private Id(String teacher_id,String student_id,String group_id){ this.teacher_id = teacher_id; this.student_id = student_id; this.group_id = group_id; } private String teacher_id; private String student_id; private String group_id; //重写hashCode() @Override public int hashCode() { final int prime = 31; int result = 1; result = prime * result + ((group_id == null) ? 0 : group_id.hashCode()); result = prime * result + ((student_id == null) ? 0 : student_id.hashCode()); result = prime * result + ((teacher_id == null) ? 0 : teacher_id.hashCode()); return result; } //重写equals() @Override public boolean equals(Object obj) { if (this == obj) return true; if (obj == null) return false; if (getClass() != obj.getClass()) return false; Id other = (Id) obj; if (group_id == null) { if (other.group_id != null) return false; } else if (!group_id.equals(other.group_id)) return false; if (student_id == null) { if (other.student_id != null) return false; } else if (!student_id.equals(other.student_id)) return false; if (teacher_id == null) { if (other.teacher_id != null) return false; } else if (!teacher_id.equals(other.teacher_id)) return false; return true; } } private Id id; private String className; private String schoolName; private Calendar createTime; private Student student; private Teacher teacher; private Group group; public MyClass(){} public MyClass(String className,String schoolName,Student student,Teacher teacher,Group group){ this.className = className; this.schoolName = schoolName; this.student = student; this.teacher = teacher; this.createTime = Calendar.getInstance(); this.group = group; //创建主键ID类的实例 id = new Id(teacher.getTeacher_id(),student.getStudent_id(),group.getGroup_id()); //创建关联 teacher.getMyClassList().add(this); student.getMyClassList().add(this); group.getMyClassList().add(this); } public Id getId() { return id; } @SuppressWarnings("unused") private void setId(Id id) { this.id = id; } public String getClassName() { return className; } public void setClassName(String className) { this.className = className; } public String getSchoolName() { return schoolName; } public void setSchoolName(String schoolName) { this.schoolName = schoolName; } public Calendar getCreateTime() { return createTime; } public void setCreateTime(Calendar createTime) { this.createTime = createTime; } public Student getStudent() { return student; } public void setStudent(Student student) { this.student = student; } public Teacher getTeacher() { return teacher; } public void setTeacher(Teacher teacher) { this.teacher = teacher; } public Group getGroup() { return group; } public void setGroup(Group group) { this.group = group; } }

pojo/MyClass.hbm.xml:

<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"> <hibernate-mapping package="pojo"> <class name="MyClass" table="A_CLASS" mutable="false"> <composite-id name="id" class="MyClass$Id"> <key-property name="teacher_id" column="TEACHER_ID" type="string" access="field"/> <key-property name="student_id" column="STUDENT_ID" type="string" access="field"/> <key-property name="group_id" column="GROUP_ID" type="string" access="field"/> </composite-id> <property name="className" column="CLASSNAME" type="string"/> <property name="schoolName" column="SCHOOLNAME" type="string"/> <property name="createTime" column="CREATETIME" type="calendar"/> <many-to-one name="teacher" column="TEACHER_ID" insert="false" update="false"/> <many-to-one name="student" column="STUDENT_ID" insert="false" update="false"/> <many-to-one name="group" column="GROUP_ID" insert="false" update="false"/> </class> </hibernate-mapping>

util/HibernateUtil.java:

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

util/Manager.java:

package util; import java.util.Iterator; import org.hibernate.Session; import org.hibernate.Transaction; import pojo.Group; import pojo.MyClass; import pojo.Student; import pojo.Teacher; public class Manager { @SuppressWarnings("rawtypes") public static void main(String[] args) { Teacher t = new Teacher(); t.setTeacher_name("fhd"); t.setTeacher_age(35); Student s = new Student(); s.setStudent_name("fuhaidong"); s.setStudent_age(30); Group g = new Group(); g.setGroup_name("group111"); g.setGroup_num(80); Session session = HibernateUtil.getSessionFactory().openSession(); Transaction transaction = session.beginTransaction(); session.save(t); session.save(s); session.save(g); MyClass my = new MyClass("class1111111", "schoolName1111111",s,t,g); session.save(my); System.out.println("T:" + t.getTeacher_id()); Iterator itt = t.getMyClassList().iterator(); while(itt.hasNext()){ MyClass my1 = (MyClass) itt.next(); System.out.println("S:" + my1.getStudent().getStudent_id()); Iterator its = my1.getStudent().getMyClassList().iterator(); while(its.hasNext()){ MyClass my2 = (MyClass) its.next(); System.out.println("G:" + my2.getGroup().getGroup_id()); } } transaction.commit(); session.close(); } }

表结构：

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