Hibernate-复合主键案例

1.设计建立后的User表（下图为hibernate自动创建的表）

userName和address作为联合主键

2.写复合主键类

package com.cx.compositeKey;

import java.io.Serializable;

/**
 * Created by cxspace on 16-7-24.

   复合主键类
 */

public class CompositeKeys implements Serializable{

    private String userName;

    private String address;

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }
}

3.写User类

package com.cx.compositeKey;

/**
 * Created by cxspace on 16-7-24.
 */
public class User {

    //名字跟地址，不能重复
    private CompositeKeys keys;

    private int age;

    public CompositeKeys getKeys() {
        return keys;
    }

    public void setKeys(CompositeKeys keys) {
        this.keys = keys;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    @Override
    public String toString() {
        return "User{" +
                "age=" + age +
                ", keys=" + keys +
                ‘}‘;
    }
}

4.配置主键映射

<?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="com.cx.compositeKey" auto-import="true">

    <class name="User">

        <!--
           复合主键映射
        -->
        <composite-id name="keys">

            <key-property name="userName" type="string"></key-property>
            <key-property name="address" type="string"></key-property>

        </composite-id>

        <property name="age" type="int"></property>

    </class>

</hibernate-mapping>

5.在总配置文件中加载映射配置和自动建表配置

<!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>
         <!--1.数据库连接配置-->
        <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
        <property name="hibernate.connection.url">jdbc:mysql:///learnstruts</property>
        <property name="hibernate.connection.username">root</property>
        <property name="hibernate.connection.password">33269456.cx</property>
        <!--
          数据库方言配置，hibernate会根据不同的方言生成符合当前数据库语法的sql
        -->
        <property name="hibernate.dialect">org.hibernate.dialect.MySQL5Dialect</property>

        <!--2.其他相关配置-->
        <!--2.1显示运行时的sql语句-->
        <property name="hibernate.show_sql">true</property>

        <!--2.2格式化sql-->
        <property name="hibernate.format_sql">true</property>

        <!--2.3自动建表,写好映射就可以-->

        <property name="hibernate.hbm2ddl.auto">update</property>

        <!--3.加载所有映射-->

        <mapping resource="com/cx/compositeKey/User.hbm.xml"></mapping>

    </session-factory>

</hibernate-configuration>

6.编写测试类测试

package com.cx.compositeKey;

import com.cx.utils.HibernateUtils;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;

/**
 * Created by cxspace on 16-7-24.
 */
public class Test {

    public void testSave() throws Exception{

        Session session = HibernateUtils.getSession();

        Transaction tx = session.beginTransaction();

        CompositeKeys keys = new CompositeKeys();

        keys.setAddress("aa");
        keys.setUserName("bb");

        User user = new User();
        user.setAge(20);
        user.setKeys(keys);

        session.save(user);

        tx.commit();
        session.close();

    }

    @org.junit.Test
    public void testGet() throws Exception{

        Session session = HibernateUtils.getSession();
        Transaction tx = session.beginTransaction();

        //构建联合主键
        CompositeKeys keys = new CompositeKeys();
        keys.setAddress("aa");
        keys.setUserName("bb");

        //查询
        User user = (User) session.get(User.class , keys);

        if (user != null){

            System.out.println(user.getAge());

        }

        tx.commit();
        session.close();

    }
}