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();    }}