hibernate基础15：组合主键1

Posted 2020-12-22 来临

1、Java实体bean类

package com.project.pojo;

import java.io.Serializable;
/**
 * 如果组合索引是类的属性时，该类必须实现Serializable
 * @author Administrator
 *
 */
public class Result implements Serializable{
    private int stuid;//学生id
    private int subid;//学科id
    private double score;
    public int getStuid() {
        return stuid;
    }
    public void setStuid(int stuid) {
        this.stuid = stuid;
    }
    public int getSubid() {
        return subid;
    }
    public void setSubid(int subid) {
        this.subid = subid;
    }
    public double getScore() {
        return score;
    }
    public void setScore(double score) {
        this.score = score;
    }
    
}

2、配置hbm.xml

<?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="com.project.pojo">
    <class name="Result" table="t_result">
        <!-- 组合索引映射 -->
        <composite-id>
            <key-property name="stuid"/>
            <key-property name="subid"/>
        </composite-id>
        <property name="score" />
    </class>

</hibernate-mapping>

3、配置hibernate.cfg.xml

<?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>
        <!-- 1、数据库连接信息 -->
        <!-- 指定数据方言 -->
        <property name="dialect">org.hibernate.dialect.mysqlDialect</property>
        <property name="connection.driver_class">com.mysql.jdbc.Driver</property>
        <property name="connection.url">jdbc:mysql://192.168.1.59:3306/hibernate?characterEncoding=UTF8</property>
        <property name="connection.username">root</property>
        <property name="connection.password">1234</property>
        
        <!-- 2、通用配置信息 -->
        <!-- 打印sql语句 -->
        <property name="show_sql">true</property>
        <!-- 格式化sql语句 -->
        <property name="format_sql">true</property>
        
        <!-- 映射文件信息 -->
        <mapping resource="com/project/pojo/Result.hbm.xml" />
    </session-factory >
</hibernate-configuration>

4、测试

package com.project.test;

import org.hibernate.Session;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
import org.hibernate.tool.hbm2ddl.SchemaExport;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import com.project.pojo.Result;
import com.project.util.HibernateUtil;

public class HibernateTest {
    Session session = null;
    Transaction ts = null;
    
    @Before
    public void setUp(){
        session = HibernateUtil.getSession();
        ts = session.beginTransaction();
    }
    
    @After
    public void tearDown(){
        HibernateUtil.closeSession();
    }
    
    @Test
    public void testCreateDB(){
        Configuration cfg = new Configuration().configure();
        //使得hibernate映射信息转换为数据库识别的dll语言
        SchemaExport se = new SchemaExport(cfg);
        //第一个参数：是否打印dll语句
        //第二个参数：是否将dll到数据库中执行
        se.create(true, true);
    }
    
    @Test
    public void testInit(){
        try {
            Result r = new Result();
            r.setStuid(1);
            r.setSubid(1);
            r.setScore(70.5);
            session.save(r);
            ts.commit();
        } catch (Exception e) {
            if(ts!=null)ts.rollback();
            e.printStackTrace();
        }
    }
    @Test
    public void testSelect(){
        Result r = new Result();
        r.setStuid(1);
        r.setSubid(1);
        r = (Result) session.get(Result.class, r);
        System.out.println(r.getScore());
    }
    
}