Hibernate 实现 多对一 例子

public class Dept {
private  Integer deptNo;
private  String deptName;

public Integer getDeptNo() {
return deptNo;
}

public void setDeptNo(Integer deptNo) {
this.deptNo = deptNo;
}

public String getDeptName() {
return deptName;
}

public void setDeptName(String deptName) {
this.deptName = deptName;
}
}

<?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">
<hibernate-mapping package="cn.hello.hql2.one" schema="happyy2165">
<class name="Dept" table="Dept" dynamic-update="true">
<id name="deptNo" column="deptNo">
<generator class="native"/>
</id>
<property name="deptName" column="deptName"></property>
</class>
</hibernate-mapping>

package cn.hello.hql2.one;

import java.util.Date;

public class Emp {
private Integer empno;
private String ename;

private Dept dept=new Dept();

public Dept getDept() {
return dept;
}

public void setDept(Dept dept) {
this.dept = dept;
}

public Integer getEmpno() {
return empno;
}

public void setEmpno(Integer empno) {
this.empno = empno;
}

public String getEname() {
return ename;
}

public void setEname(String ename) {
this.ename = ename;
}

}

<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="cn.hello.hql2.one">
<class name="Emp" table="Emp" schema="happyy2165">
<id name="empno" column="empno">
<generator class="native"></generator>
</id>
<property name="ename" column="ename"/>

<many-to-one name="dept" column="deptno" class="cn.hello.hql2.one.Dept"></many-to-one>

</class>
</hibernate-mapping>

public class text20171006_2 {

Configuration cfg;
Session session;
Transaction tx;
SessionFactory factory;

@Before
public  void before(){
cfg=new Configuration().configure();
factory = cfg.buildSessionFactory();
session = HibmentUtil.getSession();
tx = session.beginTransaction();
}
@Test
// 多对一
public  void  aVoid(){
cn.hello.hql2.one.Emp emp = session.get(cn.hello.hql2.one.Emp.class, 1);
System.out.println(emp.getDept().getDeptName());
}

}

<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">

<hibernate-configuration>

<session-factory>

<!-- Database connection settings -->
<property name="connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
<property name="connection.url">jdbc:oracle:thin:@localhost:1521:orcl</property>
<property name="connection.username">happyy2165</property>
<property name="connection.password">a123456a</property>

<!-- JDBC connection pool (use the built-in) -->
<property name="connection.pool_size">1</property>

<!-- SQL dialect -->
<property name="dialect">org.hibernate.dialect.Oracle10gDialect</property>

<!-- 使用getCurrentSession 进行配置-->
<!-- Enable Hibernate's automatic session context management -->
<property name="current_session_context_class">thread</property>

<!-- Echo all executed SQL to stdout -->
<property name="show_sql">true</property>

<property name="format_sql">true</property>

<!-- Drop and re-create the database schema on startup -->
<property name="hbm2ddl.auto">update</property>

<mapping resource="cn/hello/entity/Dog.hbm.xml"/>
<mapping resource="cn/hello/hql/Dept.hbm.xml"/>

<mapping resource="cn/hello/entity/Emp.hbm.xml"/>

<mapping resource="cn/hello/hql2/one/Emp.hbm.xml"/>
<mapping resource="cn/hello/hql2/one/Dept.hbm.xml"/>

<mapping resource="cn/hello/hql2/two/Emp.hbm.xml"/>
<mapping resource="cn/hello/hql2/two/Dept.hbm.xml"/>

<mapping resource="cn/hello/hql2/three/Employee.hbm.xml"/>
<mapping resource="cn/hello/hql2/three/Project.hbm.xml"/>
</session-factory>

</hibernate-configuration
>