Hibernate一对一数据关联(二)
唯一外键关联一.单向一对一关联
1.数据模型如下图所示：
2.数据表sql
DROP
TABLE
T_User;
DROP TABLE T_Group;
CREATE TABLE T_Group (
id INT NOT NULL AUTO_INCREMENT
, name VARCHAR ( 50 )
, PRIMARY KEY (id)
);
CREATE TABLE T_User (
id INT NOT NULL AUTO_INCREMENT
, name VARCHAR ( 50 )
, age INT
, group_id INT NOT NULL
, PRIMARY KEY (id)
, INDEX (group_id)
, CONSTRAINT FK_T_User_1 FOREIGN KEY (group_id)
REFERENCES T_Group (id)
);
DROP TABLE T_Group;
CREATE TABLE T_Group (
id INT NOT NULL AUTO_INCREMENT
, name VARCHAR ( 50 )
, PRIMARY KEY (id)
);
CREATE TABLE T_User (
id INT NOT NULL AUTO_INCREMENT
, name VARCHAR ( 50 )
, age INT
, group_id INT NOT NULL
, PRIMARY KEY (id)
, INDEX (group_id)
, CONSTRAINT FK_T_User_1 FOREIGN KEY (group_id)
REFERENCES T_Group (id)
);
3.POJO类
TUser.java
package
cn.blogjava.start;
public class TUser implements java.io.Serializable {
// Fields
private Integer id;
private Integer age;
private String name;
private TGroup group;
// Constructors
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this .age = age;
}
public TGroup getGroup() {
return group;
}
public void setGroup(TGroup group) {
this .group = group;
}
/** default constructor */
public TUser() {
}
/** constructor with id */
public TUser(Integer id) {
this .id = id;
}
// Property accessors
public Integer getId() {
return this .id;
}
public void setId(Integer id) {
this .id = id;
}
public String getName() {
return this .name;
}
public void setName(String name) {
this .name = name;
}
}
public class TUser implements java.io.Serializable {
// Fields
private Integer id;
private Integer age;
private String name;
private TGroup group;
// Constructors
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this .age = age;
}
public TGroup getGroup() {
return group;
}
public void setGroup(TGroup group) {
this .group = group;
}
/** default constructor */
public TUser() {
}
/** constructor with id */
public TUser(Integer id) {
this .id = id;
}
// Property accessors
public Integer getId() {
return this .id;
}
public void setId(Integer id) {
this .id = id;
}
public String getName() {
return this .name;
}
public void setName(String name) {
this .name = name;
}
}
TGroup.java
package
cn.blogjava.start;
import java.io.Serializable;
public class TGroup implements Serializable {
private Integer id;
private String name;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this .id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this .name = name;
}
}
import java.io.Serializable;
public class TGroup implements Serializable {
private Integer id;
private String name;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this .id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this .name = name;
}
}
3.配置文件
hibernate.cfg.xml
<?
xml version="1.0" encoding="UTF-8"
?>
<! DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd" >
< hibernate-configuration >
< session-factory >
< property name ="hibernate.connection.driver_class" > com.mysql.jdbc.Driver </ property >
< property name ="hibernate.connection.password" > 1234 </ property >
< property name ="hibernate.connection.url" > jdbc:mysql://localhost:3306/sample </ property >
< property name ="hibernate.connection.username" > root </ property >
< property name ="hibernate.dialect" > org.hibernate.dialect.MySQLDialect </ property >
< mapping resource ="cn/blogjava/start/TUser.hbm.xml" />
< mapping resource ="cn/blogjava/start/TGroup.hbm.xml" />
</ session-factory >
</ hibernate-configuration >
<! DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd" >
< hibernate-configuration >
< session-factory >
< property name ="hibernate.connection.driver_class" > com.mysql.jdbc.Driver </ property >
< property name ="hibernate.connection.password" > 1234 </ property >
< property name ="hibernate.connection.url" > jdbc:mysql://localhost:3306/sample </ property >
< property name ="hibernate.connection.username" > root </ property >
< property name ="hibernate.dialect" > org.hibernate.dialect.MySQLDialect </ property >
< mapping resource ="cn/blogjava/start/TUser.hbm.xml" />
< mapping resource ="cn/blogjava/start/TGroup.hbm.xml" />
</ session-factory >
</ hibernate-configuration >
TGroup.hbm.xml
<?
xml version="1.0"
?>
<! DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd" >
< hibernate-mapping >
< class name ="cn.blogjava.start.TGroup" table ="T_Group" catalog ="sample" >
< id name ="id" type ="integer" >
< column name ="id" />
< generator class ="native" />
</ id >
< property name ="name" type ="string" column ="name" />
</ class >
</ hibernate-mapping >
<! DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd" >
< hibernate-mapping >
< class name ="cn.blogjava.start.TGroup" table ="T_Group" catalog ="sample" >
< id name ="id" type ="integer" >
< column name ="id" />
< generator class ="native" />
</ id >
< property name ="name" type ="string" column ="name" />
</ class >
</ hibernate-mapping >
TUser.hbm.xml
<?
xml version="1.0"
?>
<! DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd" >
< hibernate-mapping >
< class name ="cn.blogjava.start.TUser" table ="T_User" catalog ="sample" >
< id name ="id" type ="integer" >
< column name ="id" />
< generator class ="native" />
</ id >
< property name ="name" type ="string" >
< column name ="name" length ="100" not-null ="true" />
</ property >
< property name ="age" type ="java.lang.Integer" column ="age" />
< many-to-one name ="group"
class ="cn.blogjava.start.TGroup"
column ="GROUP_ID"
cascade="all"
unique ="true"
/>
</ class >
</ hibernate-mapping >
<! DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd" >
< hibernate-mapping >
< class name ="cn.blogjava.start.TUser" table ="T_User" catalog ="sample" >
< id name ="id" type ="integer" >
< column name ="id" />
< generator class ="native" />
</ id >
< property name ="name" type ="string" >
< column name ="name" length ="100" not-null ="true" />
</ property >
< property name ="age" type ="java.lang.Integer" column ="age" />
< many-to-one name ="group"
class ="cn.blogjava.start.TGroup"
column ="GROUP_ID"
cascade="all"
unique ="true"
/>
</ class >
</ hibernate-mapping >
4.测试代码
// 如果在配置文件中没有cascade="all",就要先插入group信息
//插入user信息
二.双向一对一关联
需要对TGroup.java和TGroup.hbm.xml文件作修改
1.在TGroup.java中增加一个TUser类和相应的getter、setter方法
TGroup.java
package cn.blogjava.start;
import java.io.Serializable;
public class TGroup implements Serializable {
private Integer id;
private String name;
private TUser user;
public TUser getUser() {
return user;
}
public void setUser(TUser user) {
this.user = user;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
import java.io.Serializable;
public class TGroup implements Serializable {
private Integer id;
private String name;
private TUser user;
public TUser getUser() {
return user;
}
public void setUser(TUser user) {
this.user = user;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
2.在TGroup.hbm.xml中增加one-to-one配置
<?
xml version="1.0"
?>
<! DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd" >
< hibernate-mapping >
< class name ="cn.blogjava.start.TGroup" table ="T_Group" catalog ="sample" >
< id name ="id" type ="integer" >
< column name ="id" />
< generator class ="native" />
</ id >
< property name ="name" type ="string" column ="name" />
< one-to-one
name ="user"
class ="cn.blogjava.start.TUser"
property-ref ="group"
/>
</ class >
</ hibernate-mapping >
<! DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd" >
< hibernate-mapping >
< class name ="cn.blogjava.start.TGroup" table ="T_Group" catalog ="sample" >
< id name ="id" type ="integer" >
< column name ="id" />
< generator class ="native" />
</ id >
< property name ="name" type ="string" column ="name" />
< one-to-one
name ="user"
class ="cn.blogjava.start.TUser"
property-ref ="group"
/>
</ class >
</ hibernate-mapping >
这样就实现了双向关联。可以实现双向查询
package
cn.blogjava.start;
import java.util.List;
import junit.framework.Assert;
import junit.framework.TestCase;
import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
public class HibernateTest extends TestCase {
Session session = null ;
protected void setUp() {
try {
Configuration config = new Configuration().configure();
SessionFactory sessionFactory = config.buildSessionFactory();
session = sessionFactory.openSession();
} catch (HibernateException e) {
e.printStackTrace();
}
}
protected void tearDown() {
try {
session.close();
} catch (HibernateException e) {
e.printStackTrace();
}
}
/**
* 对象持久化测试(Insert方法)
*/
public void testInsert() {
Transaction tran = null ;
try {
TUser user = new TUser();
user.setName( " byf " );
user.setAge( new Integer( 26 ));
TGroup group = new TGroup();
group.setName( " Admin " );
tran = session.beginTransaction();
// 设置关联
user.setGroup(group);
session.save(user);
session.flush();
tran.commit();
Assert.assertEquals(user.getId().intValue() > 0 , true );
} catch (HibernateException e) {
e.printStackTrace();
Assert.fail(e.getMessage());
if (tran != null ) {
try {
tran.rollback();
} catch (Exception e1) {
e1.printStackTrace();
}
}
}
}
/**
* 对象读取测试(Select方法)
*/
public void testSelect(){
String hql = " from TUser where name='byf' " ;
String hql2 = " from TGroup where name='admin' " ;
try {
List userList = session.createQuery(hql).list();
TUser user = (TUser)userList.get( 0 );
System.out.println( " user name is " + user.getName());
System.out.println( " user group is " + user.getGroup().getName());
Assert.assertEquals(user.getName(), " byf " );
List groupList = session.createQuery(hql2).list();
TGroup group = (TGroup)groupList.get( 0 );
System.out.println( " group name is " + group.getName());
System.out.println( " group user is " + group.getUser().getName());
Assert.assertEquals(group.getUser().getName(), " byf " );
} catch (Exception e) {
e.printStackTrace();
Assert.fail(e.getMessage());
}
}
}
import java.util.List;
import junit.framework.Assert;
import junit.framework.TestCase;
import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
public class HibernateTest extends TestCase {
Session session = null ;
protected void setUp() {
try {
Configuration config = new Configuration().configure();
SessionFactory sessionFactory = config.buildSessionFactory();
session = sessionFactory.openSession();
} catch (HibernateException e) {
e.printStackTrace();
}
}
protected void tearDown() {
try {
session.close();
} catch (HibernateException e) {
e.printStackTrace();
}
}
/**
* 对象持久化测试(Insert方法)
*/
public void testInsert() {
Transaction tran = null ;
try {
TUser user = new TUser();
user.setName( " byf " );
user.setAge( new Integer( 26 ));
TGroup group = new TGroup();
group.setName( " Admin " );
tran = session.beginTransaction();
// 设置关联
user.setGroup(group);
session.save(user);
session.flush();
tran.commit();
Assert.assertEquals(user.getId().intValue() > 0 , true );
} catch (HibernateException e) {
e.printStackTrace();
Assert.fail(e.getMessage());
if (tran != null ) {
try {
tran.rollback();
} catch (Exception e1) {
e1.printStackTrace();
}
}
}
}
/**
* 对象读取测试(Select方法)
*/
public void testSelect(){
String hql = " from TUser where name='byf' " ;
String hql2 = " from TGroup where name='admin' " ;
try {
List userList = session.createQuery(hql).list();
TUser user = (TUser)userList.get( 0 );
System.out.println( " user name is " + user.getName());
System.out.println( " user group is " + user.getGroup().getName());
Assert.assertEquals(user.getName(), " byf " );
List groupList = session.createQuery(hql2).list();
TGroup group = (TGroup)groupList.get( 0 );
System.out.println( " group name is " + group.getName());
System.out.println( " group user is " + group.getUser().getName());
Assert.assertEquals(group.getUser().getName(), " byf " );
} catch (Exception e) {
e.printStackTrace();
Assert.fail(e.getMessage());
}
}
}